Catalina 34

General Activities => Main Message Board => Topic started by: Michael on May 19, 2008, 09:50:15 PM

Title: Carbon monoxide (?) mystery
Post by: Michael on May 19, 2008, 09:50:15 PM
On two consecutive mornings this week, the carbon monoxide gas alarm was sounding when I got to Hali.  On the first morning, the propane gas detector was also sounding.  In each case, the boat had not been used, and the engine had not been run, since the night before.  The boat was relatively buttoned up, with only the vent hatches in the head and the aft cabin having been left open.  The CO monitor read-out was in the 80-90 ppm range but subsided to zero within about five minutes after the hatches and port lights were opened.  There was no noticeable smell (such as of propane or sewer gas) in the boat.

On the third and fourth mornings, in similar conditions except apparently one, no alarm was sounding.  The exception is that the night before the third day, a co-owner checked the propane tank valve and found she could tighten it somewhat more firmly.

Recent work on the boat had included replacing the two 4D house batteries (the new batteries have removable cell caps whereas the old ones apparently didn't) and putting a marine "no odour" product into the shower sump drain and toilet-waste line-holding tank.

The carbon monoxide gas detector is surface mounted on the starboard side of the engine box in the aft cabin about a foot from the floor.  It is a Kidde (3 AA battery operated) Carbon Monoxide Alarm with digital display and peak level memory Model KN-COPP-BCA Assembly 900-0146 manufactured on October 23, 2006.  It has a five year warranty.  Its User’s Guide says it was “not designed to detect smoke, fire or any other gases.”  It is an electrochemical device.  A note in the User’s Guide says, “The following substances an affect the sensor and may cause false readings: Methane, propane, iso-butane, ethylene, benzene, toluene, ethyl acetate, hydrogen sulphide, sulfur dioxides, alcohol based products, paint thinners, solvents, adhesives, hair sprays, after shaves, and some cleaning agents.”  The unit had been powered up in March or April, 2007, and not re-powered or "peak display" tested since then.  When the “Peak Level Display” button was pressed and held (which results in the display showing the highest CO reading recorded since the last peak level test or power-up) the reading given was 159.  This was after the second morning.

I read at the Centres for Disease Control website that the "Occupational Safety and Health Administration (OSHA) has two permissible exposure limits (PELs) for CO exposure. Exposures may not be over 35 ppm averaged over 8 hours and may never be over 200 ppm."

The propane gas monitor on Hali is surface mounted within 6" of the cabin sole at the base of the galley isthmus and is a hardwired 12 volt model GS/3 manufactured by Electro Systems Inc. in June, 2002.  I haven't checked yet whether it is out of warranty.  It was sounding an alarm (occasional beeping) that does not appear to be consistent with the presence of propane (but whether it would be consistent with the presence of some other gas hasn't been ascertained yet).

Nonetheless, a check on the propane gas line is in order...but hasn't been done yet.

Hali is docked in a marina.  A powerboat across the finger from Hali was gone on the first morning that the alarms were sounding...and possibly had left shortly beforehand but that is not know yet.  No nearby boat seems to have departed or been run on the second morning.

I understand that while carbon monoxide is generally only associated with incomplete combustion, it is at least theoretically possible for carbon monoxide to be produced when hydrogen sulphide (sewer gas) comes into contact with hypochlorite, an ingredient of bleach.

My current theories are:

- there was a propane leak
- there was carbon monoxide, probably produced from a nearby boat but possibly built up the evening before when Hali was run but which caused the CO alarm to sound only after its time sampling was sufficient (after we left) and which continued until the next morning
- the most unlikely theory is that the CO was produced in Hali's drain or waste line
- the new batteries are throwing off a gas that is tripping the alarms
- more than one of the above (and therefore a gumption trap)

Comments and suggestions would be appreciated.

See a fascinating posting by sailingdolphin about CO poisoning at,2874.msg15204.html#msg15204.

Title: Re: Carbon monoxide (?) mystery
Post by: sail4dale on May 19, 2008, 10:52:07 PM
I had one that went off without any traceable reason.  I also have a RV with a detector that has worked for years.

I traded detectors and both are working well.   WHY?

I read some fine print in the writeup on the offending detector and it casually mentions that sometimes a battery charger that is near by can cause interference that sets off the unit. :think  I still don't know why but both are still working well.  You might check out the battery charger possibility -  shut it off for a while and see it the unit works right.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 19, 2008, 11:07:43 PM
Interesting.  The battery charger is very close to the propane detector but not so close to the carbon monoxide detector.  However, my working hypothesis (possibly wrong but safer than doubting the instruments, which I have learned to be wary of doing since finding a broken piston ring on an airplane engine when the magneto check showed slightly more than the expected drop in RPM) is that something bad is being detected, particularly because opening the hatches and letting the boat air has stopped the alarm from sounding.  But I will certainly add the possibility you have mentioned to the list.  Thank you.
Title: Re: Carbon monoxide (?) mystery
Post by: tonywright on May 20, 2008, 07:41:47 AM
Hi Michael

Logic seems to suggest that you have a propane leak:

1) One detector can malfunction, and give a false reading. Two going off at the same time says that there is a real problem. The chances of two giving a false reading at once are very small.

2) The CO detector says that it will register in the presence of propane.

3) Opening hatches and providing fresh air cleared both alarms.

4) Tightening the propane tank valve stopped alarms from sounding.

I would suggest a thorough check of your propane system and stove.


Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 20, 2008, 10:13:57 AM
Hi and thank you, Tony.  Yes, I completely agree that the propane system needs a thorough check.  Yet the high "peak" CO reading still concerns me.  So while I will "hope" to find a propane leak, if there is one I still won't rule out the possibility of a CO issue.  Regards. Michael
Title: Re: Carbon monoxide (?) mystery
Post by: jfssail on May 20, 2008, 10:41:22 AM
Michael, I had a similar problem last season with the same CO detecter. I had the problem when equalizing my batteries, due to the battery acid vapors produced during the equilalization procedure without adequate ventilation. You could be getting the same vapors during normal charging of your batteries in a closed spaced?
I don't think propane vapors would affect this CO detecter.

Jack F Stewart
1993 C36 #1233 "Windancer"
Port Clinton, OH
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 20, 2008, 02:23:37 PM
Thank you, Jack.  Its good to have input from those who have been in a similar situation.

Another co-owner of Hali has also weighed in.  Lionel remembered that we spilled oil on the engine during an oil change on May 13. He speculated that the burning-off of the oil produced CO.  If we count his vote, yours, Tony Wright's, and sail4dale's, the votes and competing theories now are:

Battery/battery charger related: 2
Propane: 1
Carbon monoxide: 1

We probably need to ride all the theories.

Does anyone else have any thoughts/questions?

Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on May 21, 2008, 08:47:35 AM
1.  You've identified the suspects

2.  Until you can conclusively narrow it down or eliminate one  or more you HAVE TO continue to consider all three

3.  You need to develop and implement a plan to begin to conclusively eliminate them one by one

4.  Once you determine the cause, you'll obviously need a fix to avoid recurrence
Title: Re: Carbon monoxide (?) mystery
Post by: joe on May 21, 2008, 10:32:36 AM
it would seem to me that if you enclosed your monitor in the battery compartment the alarm would go off pretty quickly if that were the problem
Title: Re: Carbon monoxide (?) mystery
Post by: Craig Illman on May 21, 2008, 10:40:18 AM
One other consideration is that it could be a combination of two as well.

Title: Re: Carbon monoxide (?) mystery
Post by: tonywright on May 21, 2008, 11:27:19 AM
It might be worth trying to find a tech with the appropriate detection/analsysis equipment. (Might be worth giving the local fire dept a call, they might be interested in helping you track down the problem on a slow day..?). There are detectors out there that can tell you exactly what you are looking at, and will help sniff out the precise location of a leak. Bacharach is a name of manufacturer that comes up if you google. While their basic detectors only cost $300-500 each, it is probably more than the average sailor wants to spend. On the other hand, proving the presence or absence of a propane leak - priceless?

I wonder if there is somewhere that rents them by the day?

Of note is that CO detectors apparently need calibration every 1 -2 years.


Title: Re: Carbon monoxide (?) mystery
Post by: Ron Hill on May 21, 2008, 06:47:52 PM
Michael : I don't believe that propane will confuse a CO detector.
I'd send that detector back to the company for a check and/or have the local Fire Dept (as suggested) take a look at it!  CO detection is something that you don't want to miss!!  A thought
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 21, 2008, 09:54:55 PM
Ron, Stu, and everyone else who has weighed in, thank you for your input.

Heeding the advice so far, I will continue to assume there is danger of CO poisoning, battery fume poisoning or explosion, and propane explosion, ...but that something else also might be at work. 

Tony's idea, seconded by Ron, of asking the fire department to investigate seems a good one.  Or, with the CG station almost next door, their dock may be a first port of call.

I have now emailed the alarm companies for feedback.

There has been no peep of an alarm since those first two mornings...but they rattled the cage well.

Thanks again.  I'll post the conclusion (all going well) but meanwhile if anyone has further thoughts they are welcome.

Title: Re: Carbon monoxide (?) mystery
Post by: Randy and Mary Davison on May 22, 2008, 07:37:41 AM
On Gorbash, my CO detector goes off anytime the boat is closed up and the batteries are charging heavily.  The same detector trips at home when I leave in my office/ham shack closed up with the 4d I use for radio equipment charging heavily.  I've read that some CO detectors are sensitive to battery charging fumes.  This one certainly is.  I have another one to try out.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 22, 2008, 10:44:55 AM
The propane gas alarm manufacturer, Electro Systems Inc., kindly provided the following response:

"From your description of the situation, our best guess is that the
batteries are discharging Hydrogen, which could trigger the GS/3
propane sensor, which is designed specifically for propane, but is
sensitive to most hydrocarbons. A description of the way it works is on
our website at:

We don't know if hydrogen could trigger the CO detector.

....the fact that your co-owner could tighten the propane valve...
suggests a small propane leak may have occurred. Propane has a compound
called mercaptan added as a safety precaution to make it smell so you
notice a leak. It is usually described as smelling like rotten cabbage...

I hope this is helpful. Kidde should be able to provide some insights
on the CO alarm."

With that input and Randy Davison's, the betting continues to favour the batteries as the cause of the alarm(s) sounding.  But we will keep propane and carbon monoxide, like Hilary Clinton, in the race.

Title: Re: Carbon monoxide (?) mystery
Post by: tonywright on May 22, 2008, 06:50:24 PM
Great info Michael and others. I would have to agree that the batteries now sound like the most likely source. Seems like installing a good venting system for when the batteries are being charged is a really good idea. Those gases can be pretty explosive, so the alarms warning you are doing so for a good reason!

It would explain why the alarms are no longer sounding, since the batteries by now are probably fully charged, and so are giving off less gas. They must have had a fairly low charge when they were first installed?


Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 24, 2008, 11:54:09 PM
The following is the latest update on this carbon monoxide - propane - hydrogen from batteries or ??? mystery, from one of Hali's co-owners:

"I should have sent this last night, but I did record the following in the
log book. When I arrived at Hali last night - 6:15pm - the propane alarm was
sounding off every few minutes. I opened the hatches and the alarm stopped
within 5 - 10 minutes. I checked the [carbon monoxide] detector and it showed a reading of
52 but there was no audible alarm. I had a good look around Hali to ensure
that the propane tank valve was tightly closed, and that the propane system
switch was in the off position - both affirmative. There was no smell of
propane in the cabin.
That is about all I can report other than it was a great night for a sail."

[Note by Michael.  As perhaps noted previously, the CO detector user manual indicates that it is a time-sampling device.  Apparently, the alarm will sound when certain concentrations persist for certain time periods.  I speculate that in this case a sufficient level of CO (or whatever is activating the alarm) had not persisted for long enough to trip the audible alarm.]

Title: Re: Carbon monoxide (?) mystery
Post by: Jon Schneider on May 25, 2008, 05:14:13 AM
It's really sounding like the battery charging is the culprit, but just for S&Gs, try taking the propane tank off the boat to see if the same event occurs after she's sealed up again.  Also, your LPG solenoid switch is off, right?  I suppose it's possible that even with the tank valve tightly closed, there's a leak in it, and if the solenoid is routinely left on (but why would anyone do that?), then perhaps the tank is still in the running as a the culprit.  BTW, you might want to check that your charger is working properly (i.e., putting out the right voltage, adjusting to the right stage, etc.), and you might want to check to see how the fluid level is in your new batteries.  Charging enough to cause these sensors to trigger sounds pretty high to me.  Do you leave the fridge or any other power-hungry device running while you're away from the boat?  If so, the second test you might want to run (if the charger checks out) would be to turn those appliances off; in fact, turn the charger off and don't plug in.  If that solves the problem, you'll have discovered the culprit.  BTW, thanks for an incredibly detailed and interesting write-up of the problem and situation. 
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 25, 2008, 09:29:34 AM
Thank you for your suggestions, Jon.  We will try them on Hali.

According to our standard procedures, when we leave Hali, we leave shore power connected, battery charger on, all elective electrical devices (including 12 volt Adler Barbour refrigerator and propane solenoid) off, and dual house battery selector switch at off.  Therefore, the only electrical devices that will operate are the battery charger and the direct-wired bilge pump.

We are getting more water in Hali's bilge than I think proper.  This is another unsolved mystery.  Its relevance to this discussion is that the bilge pump consequently cycles on relatively frequently:  I would say about 6-12 times a day.  I suppose this regular draw on the batteries results in frequent charging of the batteries and, in our "battery gas is responsible" thesis, the regular production of hydrogen gas that activates the propane gas detector (and, it now seems possibe - see below - the CO detector).

As mentioned previously, a recent change aboard Hali was the replacement of the two old 4D batteries with two new (Interstate) 4D batteries.  I checked the fluid level in only one cell of the new batteries at the time (May 13) of installation.  Thanks to your suggestion, Jon, I will now check the fluid level in all the cells and realize I should have done that at the time of installation.

Thanks again.

AMENDMENT: Since writing the foregoing, I have learned that hydrogen gas will activate CO monitors.  At least, the fact that hydrogen gas will activate CO monitors is the basis for a patent application ( for a device to test CO monitors by generating activating samples of hydrogen at the CO monitor.  And the fact that hydrogen gas will activate CO monitors is mentioned in another patent application (  Both these patent applications have interesting things to say about domestic CO monitors of the type that I guess most of us use aboard our boats.  Assuming the patent applicants are right that hydrogen activates CO monitors (and I have no reason to think otherwise but also no understanding of the monitoring device or chemistry that would enable me to say one way or the other), and that, as Electro Systems Inc. has given as their "best guess", that the charging of the batteries aboard Hali is producing hydrogen that is activating the propane gas alarm, it seems we have some basis for saying that the charging of the new batteries on Hali could be causing both the propane gas and CO gas detectors on Hali to sound their alarms.  So one further useful thing to do will be to test for hydrogen gas on Hali.  I think it was Tony Wright who suggested above doing tests for specific gases.


Title: Re: Carbon monoxide (?) mystery
Post by: Ron Hill on May 25, 2008, 06:42:38 PM
Michael : Off of the CO topic, but you should get some Gore Dripless pack or at least go to Radio Shack and get a counter that you can wire into the bilge pump and KNOW exactly how many times the pump is cycling for sure!!   A thought. 
Title: Gore Dripless Packing (was "Carbon monoxide (?) mystery")
Post by: Jon Schneider on May 25, 2008, 07:42:56 PM
Ron, do you know if it's possible to switch to the Gore packing while the boat's in the water?  Or at least remove one or two lines of current packing and replace them with Gore while you're in the water?
Title: Re: Carbon monoxide (?) mystery
Post by: dave davis on May 25, 2008, 09:01:30 PM
It looks like you are getting lots of inputs and some very good ideas.
 I would not rule out the propane possibility. I had a resent CO alarm in my house and it was due to a plumber igniting his propane torch so that he could solder the copper piping in the bath room. The alarm unite was about 15 feet from his work. The alarm was immediately set off as he was lighting his torch. I don’t know if the alarm is sensitive to the raw propane or to the byproduct of the flame.  By taking the unit outside, the alarm stopped immediately.
You might also examine the valves and the tubing by using a bubble/soap method to look for leaks in and around your propane tank.
As was previously suggested, I have had the gas company come out to the house and they had a snifter to search for leaks at no charge.
Another approach you might try is to use the alarm unit as a detector.  Place it in the battery well while you are charging and or in the charger compartment while you a charging. It may act as a good snifter and will help isolate the source.
Good Luck, Dave
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 26, 2008, 01:28:51 PM
Regarding the propane/CO/hydrogen/?? issue:

1.  The CO monitor was reading in the 70s at the boat yesterday afternoon (before we removed the propane can, before we ran the engine, and before we aired out the boat). No combustion engine appeared to be or to have been operating in the vicinity. The CO monitor readings dropped to nil within about 10 minutes of our ventilating the boat.
2.  After our short cruise, we took the propane can off Hali as Jon suggested.
3.  Dave, thanks for your information.  We have never smelled propane but I will not rule any possibility out yet.

Ron - Thank you for the suggestions re: stuffing box and bilge pump. At the last change, we did not use Goretex dripless stuffing but can/should re-do the packing now that we have some on hand.  I had thought vaguely about getting a counter to measure how often the bilge pump cycles on.  Your suggestion has brought the issue to the fore.
Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on May 26, 2008, 08:34:57 PM
1.  Check the hose clamp on the bilge pump hose connection.  Mine let go a while ago and the pump ran continuously for a week until it dropped the house bank below 10.5V.

2.  Why do you leave your boat plugged in?  What needs to be charged if everything is OFF?  Only thing I can think of is the bilge pump.

3.  Much very good advice on the issues and step-by-step checks on the CO stuff.

4.  ANY stuffing box can be done in the water.  See Projects and FAQs for descriptions and discussions.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 26, 2008, 10:24:46 PM
Stu, thank you.

1.  Your point ('why leave the boat plugged in') indicates a good next-step test (after we find out whether the alarms still go off with the propane can off the boat), namely, to unplug Hali from shore power (or at least turn the mains battery charger switch off) so that no battery charging takes place when we are not at Hali.  It seems so obvious...after you mention it.  (Is it your view that the boat should generally not be plugged into shore power?) 

2.  We changed the bilge pump line and put on new 316 ss hose clamps late last summer.  The pump seems to discharge a good deal of water overboard.  But I will check the hose clamps anyway.

3.  To second your comment about changing the stuffing when the boat is in the water, we certainly have found it easy (after reading the great posts on this site about doing it).  Nonetheless, three or four of us were on hand, armed with rags and screwed-up courage on the first occasion. 

Amendment: Since writing the foregoing, a co-owner has emailed:

"We were out on Hali tonight for a short sail and drift. The propane alarm
was sounding when D. arrived - the alarm cleared once she opened the
companionway. My brother, E., a heavy duty mechanic in his previous life,
was with us again tonight. He and I had talked about our alarm situation
when we were out last week. When I told him about the hydrogen theory, he
thought that was a distinct possibility but also thought that it might
manifest itself in a warm to hot battery (and it there was a hot one we
should get it out of there because batteries can explode). We checked the
new batteries. One cell of one of the batteries seemed a little warmer than
the others but it was almost imperceptible. No immediate danger there. We
did not think to check the starting battery. When we were leaving, I noticed
that you had removed the propane tank to eliminate that possibility - E
suggested we might disconnect the battery charger for 24 - 48 hours and
check daily to see if the alarm was still going off.
I will call the battery supplier tomorrow and ask if they have a way to
determine if a battery is giving off hydrogen gas but disconnecting the
battery charger might be worth a try. What do you think?"

And I replied:

"Great report.  Great idea to disconnect the battery charger
or leave shore power off.  Co-incidentally, Stu Jackson, who I think
is an electrical engineer, suggested doing that in a post he made on
the "Carbon monoxide (???)...." thread on the website today.
Clearly, great brains think alike!  After reading Stu's post, I was
tempted to call you to find out how things had gone tonight...but
desisted because of the late hour.  Then N. (a Blackberry addict)
came home and said, L. has sent an email about Hali.

Now that we have had alarms sounding when no propane is on the boat
(or almost no propane...I guess there might be a bit left in the
lines), it seems that we can discount the possibility that propane
aboard Hali is triggering the alarms. (I suppose we can't yet discount
the possibility that an activating gas of some sort is reaching Hali
from elsewhere.)

So I agree that as a next step we should shut off the battery charger
(or unplug the shore power)."

It will be interesting to learn what the battery manufacturer has to
say. "

Title: Re: Carbon monoxide (?) mystery
Post by: Jon Schneider on May 27, 2008, 04:03:35 AM
Michael, I'm sure you realize this, but simply unplugging the shorepower charger won't relieve you of fixing the problem.  Someone will need that charger after a day or two out upon arrival at transient marina, but it would certainly be unsafe, despite the alarms, to plug in.  If it turns out to be the charging process, it needs to be fixed.  It can't be good for the batteries, and it sure can't be good for people sleeping aboard even if the levels are slightly below the alarm trip. 
Title: Re: Carbon monoxide (?) mystery
Post by: tonywright on May 27, 2008, 06:31:54 AM
Of course if your bilge pump is cycling as much as you think it could be, then you would not want to leave the boat for too long with the charger disconnected (as someone said, more boats sink at the dock than at sea).

On Vagabond I generally have a dry bilge. I don't recall there ever being enough water in it to trigger the bilge pump (other than when I drain the HW tank). If I find any water in it, I mop it out, since it is too low for the bilge pump to suck out. As a result, when I leave the boat I make sure than all thru hulls are closed, and turn all electricals off. I only charge every couple of weeks, or after a weekend trip.

Michael, I don't recall whether you have a solar powered vent installed on Hali. If not, have you thought of putting one on? ( I have the vent, but haven't got around to installing mine yet: I'm still screwing up the courage to drill a 4" hole in the hatch!). Obviously you need to find the source of the gas and fix it. But having a vent continuously expel it in the mean time seems like a good idea?


Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on May 27, 2008, 01:52:10 PM
Is it your view that the boat should generally not be plugged into shore power?

Michael, In all of our years with Aquavite and in earlier boats [celebrating our 25th year of sailing on SF Bay this past weekend], we never left our boats plugged in, and none of 'em sank!  The reason is basic:  we just do not know how poorly wired our neighbors' boats may be.  Stray electrical can come from a bad dock wiring design or installation [not in our marina, though] or from poorly wired other boats even to a good marina system.  We intend to have the zincs continue to do their work and not spend money on a new shaft or propeller if we can help it.

That said, I've learned a lot recently from John Nixon, a frequent contributor to this Message Board.  Once I [finally] installed our Link 2000, I learned two very important things:  1) my "energy budget" done in my head for the past ten years was pretty much right spot on (see:,3976.0.html); 2) my estimate of input TO the house bank FROM the various charging sources was NOT very good because I hadn't taken into account the acceptance rate of the batteries and the tapering off of the charging amperage even with a smart regulator and a smart three stage Freedom 15 inverter charger.

In discussions by email with John, as a result of what I term "Fridge Follies," wherein I was doing detective work on why our fridge would not restart during the second night at anchor, I learned two things:  1)  equalize your batteries regularly to avoid diminished performance [assuming your batteries are wet cells and your manufacturer says it's OK to do so]; 2)  John provided this: "Leaving lead acid batteries on float charge 24/7 will reduce the useful life of the batteries by as much as 35 to 40% compared to cycle charging, which by definition is to charge them only when they need recharging, then leave them alone. The continuous float charge results in accelerated positive grid corrosion, which has the effect of turning the positive plates in the battery into mush: a soft, expanded material that produces increased internal resistance and decreased deep cycle capacity. I only use cycle charging on my boats now, but I will leave them overnight or maybe for a day or 2 with the charger on just to make sure that they get fully recharged." 

I noted that in order to do so, I'd start a program of plugging into shorepower to top off the batteries once I got back to the slip before I left.  He added: "I doubt that an extra 30 minutes with the charger on when you get back to the dock is going to get your batteries fully recharged: that last 5% or so takes a long time, even with the very low internal resistance of AGM batteries like I have on our boat. If you are adverse to leaving the charger on all the time when you are away from the boat ( which I support completely, but not for the reason you might think...), a good simple way to give the charger time to do its work is to put it on a cheap/inexpensive 24 hr time switch with the ON peg pulled out. Just set it to run for 24 hours when you leave the boat: manually start it with the timer set just after the OFF pin, and it will dutifully turn itself off after a good 24 hour charge. In most cases, that will generally make sure that you have reached that 100% charge that the batteries need to not begin loosing capacity due to sulfation. 

So, for many reasons, it's important to both keep your batteries fully charged, avoid keeping them plugged in 24/7 on float, and take care of them.  I am constantly amazed at the number of plugged in boats that NEVER GET USED.  Whenever the owner comes down to the boat, there are going to be a bunch of things that don't work, most importantly their electrical systems.

The fridge works much better now after the equalization, which I intend to do more regularly now that I know.  The voltage used to drop to 12V whenever the fridge started running.  After the equalization the voltage remains high and only slowly tapers off after fridge run time and during the off cycle of the fridge, the voltage actually rises a bit.

Live and learn.
Title: Charging after a sail (was Carbon monoxide (?) mystery)
Post by: Kyle Ewing on May 27, 2008, 02:43:20 PM
Regarding partially discharged batteries and leaving the battery charger on when the boat is unattended, how do people handle leaving the boat after discharging the battery (i.e. after an overnight cruise with little motoring) then closing up the boat for the weekend? 

I dislike leaving partially discharged batteries and dislike more leaving power to the boat, especially if I might be away for a week or two.  I leave the charger on while unloading and closing up but know the batteries need more than an hour of charging.

Title: Re: Carbon monoxide (?) mystery (and should shore power left on ???)
Post by: Michael on May 27, 2008, 08:34:02 PM
1.  Tony, like you, I would be apprehensive about cutting a hole in the hatch for ventilation.  In any event, I think we are agreed that the root cause of the alarms' being triggered needs to be found and eliminated.

2.   The first step in the current plan is to continue to leave the propane tank off Hali, blow the propane lines clear, vent then button up Hali, and leave the battery charger on.  If the alarms still sound, we can discount the theory that onboard propane gas is triggering Hali's propane and CO alarms.

3.    The second step will be to shut off the battery charger, check the alarms for a couple of days, then turn the battery charger on.  If the alarms don't sound when the battery charger is off but do sound soon after it is re-started, we can (I think) be reasonably confident that gas produced during battery charging is causing the alarms to sound.

4.    From Stu and Ron's posts, I take that a cause may lie deeper: e.g., the packing in the stuffing box is worn out; too much water is getting through the stuffing box; the excess water from the stuffing box is causing the bilge pump to cycle on frequently, which draws down the batteries; the drawn down batteries are requiring frequent charging; the frequent charging produces hydrogen gas; the hydrogen gas triggers the propane and CO alarms.  If some such chain of cause and effect is at play, it will, interestingly, have been an alarm about a gas leak that led to our dealing with a water leak.  (Of course, we should have dealt with the water leak in its own right.  Also, I suppose that if the water-leak-triggers-alarms theory proves true, just because we fix the water leak won't mean we have solved the gas-from-charging-batteries issue as the batteries could need charging for other reasons at other times and would then still produce hydrogen gas at potentially dangerous levels.)

5.   Stu, I am afraid that the details of your good long post on batteries and charging will be over my head until I read a book on batteries (again!).  But I suspect the post will be of interest generally.  Would you post it as the start of a new thread so that it is not wasted in this carbon monoxide desert? If you do that, I would be pleased to post some follow up questions to you about what you have posted.

Sorry about subjecting readers of this thread to my rather tortuous "thinking aloud" about Hali's alarms problem...but your input in response is really helpful.

Title: Re: Carbon monoxide (?) mystery
Post by: Randy and Mary Davison on May 28, 2008, 09:51:28 AM
A few facts and opinions...

Facts (from Wikipedia):  Wet lead acid batteries start gassing at 14.1 to 14.4 volts.  The gasses generated are hydrogen and oxygen due to electrolysis.  The concentration of hydrogen required to support combustion is 4% to 75% ( ).  Assuming I did my math correctly, 4% equals 40,000 ppm.  My CO detector, like the one mentioned in this thread, shows 40 to 200 ppm when in the boat or a small room with the batteries being charged from a fairly low state to full charge by a 3 stage regulator.  This means the hydrogen concentration in the boat is less than .5 percent of the concentration required to support combustion.

Observations and opinions:

All batteries give off hydrogen when charging and copious amounts when charging at higher rates.  I can hear every wet battery I own bubbling off oxygen and hydrogen when charging at even moderate rates.  Your batteries will vent hydrogen in the later bulk and float stages of charging.  It's normal and not something that needs to be "fixed."

Assuming that the current inexpensive CO detectors respond to virtually any hydrocarbon at roughly similar concentrations (a potentially dangerous assumption if they are less sensitive to hydrogen) than the false alarms we're getting are irritating but not dangerous.

Now, that said, here's what I do to keep my rear end safe from bad assumptions or erroneous calculations:  I make sure the boat is well vented with the dorades and solar powered vent.  We leave the hatch in the head open 2 inches with a screen in it.  Then I pull the batteries from the CO detector when we leave the boat so the marina manager doesn't call me in the middle of the night!

One concern I still have is with the hydrogen concentration in the battery box itself.  It's not vented and could build up a pretty high concentration of hydrogen and oxygen.  When I know the battery bank is down more than 50% (kids with video games), I lift the cushion and prop the cover up.  The solution is to put a simple vent in the compartment.  It's on the list.

A side comment:  For those of you still using ferro-resonant chargers, they hold voltage constant at 14 to 14.2 volts.  From the above gassing voltages, you can see why they kill batteries fast.  I suspect the reason some folks don't have problems is that their units are holding a voltage just under the gassing voltage.  The one I tossed over the side when we bought Gorbash was holding 14.2 and the PO complained of short battery life.

 (Note, I can always hear slight bubbling from any battery I charge at high rate - this is oxygen and hydrogen boiling off)
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 28, 2008, 10:33:08 AM
Randy, your post might well revive Tony's "hole-in-the-hatch" suggestion for Hali!  Thank you for the battery gas information.  Hali's two house batteries are located under the settee. I share your concern about gas buildup there.

We are off to purge Hali's propane line.
Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on May 28, 2008, 06:45:04 PM

Michael, in the spirit of our last long communication about your fuel pump wiring issue see:,3347.msg21788.html#msg21788 (,3347.msg21788.html#msg21788), I have reviewed the items mentioned in this thread and offer these ideas:

1.  You may want to consider having all of the owners present at one time.  It seems cumbersome for you to be emailing each other with varying ideas about what's happening.  I do recognize that perhaps your schedules may preclude this, but give it a try.  There may be some small advantage to having different people there at different times, but your reports indicate that you are all getting the same results, so quit while you're ahead.   :D

2.  In conjunction with that idea, your presentations of the alarm(s) are based on AFTER conditions.  You have NEVER, as far as I've heard, been onboard to observe the START of the alarm(s), only when you come onboard later.  You NEED to start to think about getting there and REPLICATING the conditions when you FIRST "close up" the ship.  CLOSE UP may be exactly the problem because earlier threads have indicated that Mark IIs exhibit much less air flow because of the lack of the Dorades on the Mark Is, even with the head and aft cabin vents open.

3.  The battery charging SYSTEM appears to be the culprit.  I was equalizing my house bank just today and found that VIGOROUS gassing does occur, as Jack mentioned clearly.  Go on your boat, close it up, and start the charger.

4.  You NEED to carefully monitor your charger.  We have no idea of what equipment you have onboard.  Please TELL US. It could be toast or could be a good unit gone bad.  With your small house bank of (2) 4Ds - you didn't say if you have a separate start bank, so if you're using one per day they're both gonna need a hefty charge - your charger is going to be PUTTING OUT (as they say) and gassing the cells when you return from a weekend.  The fact that you CHANGED from sealed 4-Ds to open cells is almost a giveaway.  Geez, I have NO idea where anyone would get CLOSED 4Ds.  You're almost lucky you got rid of those.  Please, tell us more about your charger and banks setup and how you use your boat (i.e., anchor out or marina hopper).

5.  Water in bilge:  I checked this just today for you with our Link 2000.  4 amps when bilge pump is running. Let's say it runs for one minute every 1/2 hour.  2 times an hour times 4 amps divided by 60 minutes = 8/60thsd or about 1 big flipping  amp hour!!!  Did I get the math right?  With a 4D you could run that puppy for days without having a problem, unless you weren’t coming down to your boat for more than a month.  You NEED to do an energy budget on your bilge pump, to see if I'm anywhere near close.  Fix the leak.  It could also be from your rudder stock, see Projects on the website.

6. Randy's analysis mirrors this one.  Tony Wright narrowed it down to the charger and batteries.

7.  Do you have a Link or other type of battery monitor?

Summary:  Get everyone together.  Do an energy budget on your bilge pump.  Continue your analysis.  Arrange to get INSIDE the boat to WATCH WHAT HAPPENS when you close it up.  Carefully consider additional passive ventilation.  Consider getting a solar panel to offset the bilge pump draw.  Answer Kyle Ewing's question in your own head(s) about HOW you USE your boat and what the condition of the bank(s) is when you get back to your slip.  Check and if necessary replace your charger.  Equalize your house bank.  Consider a separate start bank - many items I've written about the advantages for your own security and the health of the batteries themselves,

I must admit, happily, that you and HALI have provoked some very important and interesting threads, and that the contributions of so many of our members have been very encouraging.

I don't think you have a problem, I think you have an overactive and too sensitive monitoring system, unforeseen conditions from a good idea, pretty much like the results of our last long thread about your engine wiring, especially about the difficulty of bleeding resulting from your wiring which requires holding the spring switch open -- that needs two people -- I just installed a fuel pump shutoff switch in our engine compartment and that switch couldn't make bleeding easier.   8)
Title: Re: Carbon monoxide (?) mystery
Post by: Ron Hill on May 28, 2008, 06:54:24 PM
Guys : I'm not sure why Catalina didn't do it, but the first teak vent (approx 5x7") that I installed on my C34 back in 1989 was for the battery compartment under the settee. 
Seemed to me to be necessary and I'm glad that I did it. 
Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on May 28, 2008, 08:04:56 PM
One could consider that the "proper" ventilation that Ron added would exacerbate the CO monitor problem by allowing "vapors" to get out of the battery box.

It's always a good idea to do what Ron did, and so few have done so (me included).  I made darn sure the battery enclosure tops were off when equalizing today - it does make a noticeable smell, too.

Back to you, Michael.
Title: Re: Carbon monoxide (?) mystery
Post by: Kyle Ewing on May 28, 2008, 10:52:22 PM
If charging seems to be the culprit, move the CO detector closer to the batteries or but it in the battery box while charging and see if it goes off to prove or disprove the theory. 

Where is your detector located?  For what it's worth carbon monoxide is neutrally buyoant.  Propane is heavier than air.  What gases might accumulate where your detector is?

Were you cooking with the propane stove before it went off?  Years ago I was cooking with the cabin closed.  Several hours after going to bed my CO detector went off.  I opened the hatches for a few minutes then closed them again to vent.  The CO detector went off again about an hour later.  I slept with a hatch open the rest of the night.  Since then the CO detector hasn't gone off.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 28, 2008, 11:00:34 PM
This is a great discussion board.  It is sufficient reason by itself to buy another Catalina 34 if we ever sell Hali.


1.  Thanks for posting your battery charging post as a new thread.  I see it is getting lots of hits. I have questions but won't get around to asking them on that thread for a bit yet.

2.  Unfortunately there is no chance of us getting all four families of owners of Hali, or even all the principals, to Hali at one time but one other owner and I are headed there tomorrow evening.

3.  Thank you for suggesting a methodical approach. (You are an engineer, aren't you?  Most of my family have been engineers.  I may have said this before: when we were kids and people had those home-made car top carriers and one went by that was neat as a pin, tied up perfectly, my father would say, after waiting a minute, "There went an engineer" or words to that effect  And after a cartop carrier went with tarp and ropes flapping about, he would wait a minute and then say, "There went a lawyer".  Cripes, and I grew up to be a lawyer.)

4.  Lionel has had a chat with the battery manufacturer...who thinks if there is a problem it is likely caused by the charger. (Which reminds me of the lion who comes upon a painter.  The painter shows the lion his painting of a soldier spearing a lion and asks the lion, "How do you like it?"  The lion answers, "If a lion had painted it, it would look different.")

5.  Hali has a starting battery (bought at Costco last year, can't remember the make offhand) separate from the two 4D house batteries.  It is located adjacent to the propeller shaft.

6.  Hali's battery charger is a Flyback 20-3 Alltech Series.  Not sure whether it was original equipment (1997 boat) or purchased by the previous owner.


If Lionel/other owners will agree, we will put a vent into the battery compartment under Hali's settee as you did on your boat.  Perhaps even add Tony's "through the hatch" vent (although I am bridling at that one a bit).


Hali's CO monitor is located on the engine box in the aft cabin just up from the cabin sole.  Putting it temporarily in the house battery compartment seems a good "test".  We also now have a second CO monitor in the forward cabin, starboard side, just forward of the hanging locker.

Hali's propane monitor is located 6" above the cabin sole at the base of the galley "ismuth" opposite the chart table and, therefore, immediately adjacent to the house battery compartment beneath the settee.

We haven't been cooking or using the propane at all recently.  Nor have we been running the diesel heater.  The only combustion aboard recently has been in the diesel engine...and it has not triggered the CO monitor (although I say that recognising that CO might in fact have been coming from the engine and not triggering the CO monitor until the monitor met its time-sampling threshold).


Didn't get to the boat to blow the propane line clear today.

Again thanks to all for the continuing feedback.


Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on May 28, 2008, 11:49:53 PM
Yes, I am an engineer, not a lion!

Michael, you NEED to go to the top of this page to the "SEARCH" box, and type in the word "flyback" and then click on the search button.  The first four or six hits on those results will tell you more than you need to know about your charger.  Get rid of it NOW if you want to avoid buying new batteries, yet again, as early as next week.

Please, please, please, do the search and read that stuff, and then make up your own mind(s). 

Among them, you'll find this one, read especially reply #6:,3716.0.html

It's your charger that's creating your problem.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 29, 2008, 12:34:14 AM
Stu, I will head for Hali in the morning to turn "off" the Flyback 20-3.  That might interfere with the differential diagnosis of the alarm sounding problem....but perhaps save our new batteries.  The odd thing is, I think I had read those postings about the Flyback 20-3 a year or so ago, but put them out of mind as we were getting good life out of our then nearly five-year old 4Ds.  In fact, there never seemed to be a problem (would I know if there was one?) until we got the new 4Ds on May 13.  I hate to admit it, but we got the new batteries not for any well-considered reason other than that they [the old batteries] were five years old and we were getting nervous about using them through another cruising season.  We hadn't tested them [the old batteries] but I had noticed the windlass was slowing when [we] last used [it]. (And now the windlass doesn't work....I wonder whether there is a connection?  But it could be that the jury-rigged mechanical connection of leads I made last year has worked loose.)  Thanks for pointing me to the Flyback [20-3 Alltech] problems posts.   
Title: battery box venting
Post by: Jon Schneider on May 29, 2008, 05:15:31 AM
I delayed venting my battery box for a couple of years, too.  I even bought a lovely teak vent and stowed it in the battery box!  Somehow the idea of jigging out the large rectangular hole, finding a way to seamlessly attach the vent, and varnishing it just never made it to the top of my list.  Then I saw these 3" plastic vents at a local WM:  All you need is a drill and a 3" hole cutting attachment.  The box (at least on my 1990) is constructed out of two thin layers of glass, easy as "butta" to cut through.  Put one of these nearly-invisible vents on the center aisle side and one on the forward side.  I'd like to say it's a 15 minute job -indeed it feels like that- but it's probably actually an hour-long job by the time you get the batteries out (you'll probably need to remove at least one to ensure you don't drill through it), cut, fasten, clean up, and reinstall the batts.  It's really about the simplest safety improvement you can make on your boat. 
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on May 29, 2008, 02:21:46 PM
At Hali this morning:

Stu, to answer your question here about battery monitors aboard Hali, other than the two analogue voltmeters on the electrical panel and an analogue voltage meter at the pedestal, there are no battery monitoring devices aboard Hali.  We recognise this needs to change.

Randy, thanks for the battery gassing and hydrogen combustion information.  Wikipedia is darn useful, isn't it?  One of the many residual questions in this matter is whether a CO monitor that reads say 200 ppm in the presence of hydrogen is really indicating that there are 200 ppm of hydrogen.  Unlike the Electro Systems Inc. people who very promptly replied to my inquiry about their propane monitor,  Kidde has not yet responded to a request I sent from their website asking how to contact them about the CO alarm issues - so I have not yet been able to get information of this sort from someone knowledgeable about the CO monitor.

Jon, thanks for the link.  I see those little vents cost $3.99 each.  The price is right.

May 30 update: No alarms sounding.  Battery charger still off.
Title: Re: Carbon monoxide (?) mystery
Post by: Randy and Mary Davison on June 01, 2008, 06:24:26 PM

I agree with virtually all on the board that you would be much better off with a new charger.  I changed mine out less than a month after I bought Gorbash in '98.

That said, there is an easy measurement you can make that could buy you some time to make your charger decision.  If you let your charger take your batteries to full charge and then measure the float voltage with a digital multimeter, you can make an informed decision about how urgent your charger change needs to be.  Will assume temp in boat is 45 to 75 degrees or so.

Here's my opinion on voltages after full charge:

Above 14.1   Don't turn the charger on again.  It's cooking your batteries.

13.9 to 14.1  Will cook them over time, if for no other reason that they will use a lot of water and you or other owner will forget to check and top them off.  It only takes once.

13.8 to 13.9   Ok for well built batteries.  Watch water use at top of voltage range.  Depending on temperature, optimum float is 13.4 to 13.7, which is what chargers like the Tru-charge will hold them at.

Hope this helps. Any garden variety digital multimeter like those from Radio Shack will make an accurate enough measurement for this purpose.  Don't count on an analog meter, especially the panel type that comes with the boat.


Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 02, 2008, 10:55:42 PM
Thank you, Randy.

We do need a little time to make the charger decision, and it would be helpful to test to learn whether we could, meanwhile, use the old Flyback 20-3 charger without cooking the new 4D house batteries.

The charger has been disconnected for days now, during which time we have had no alarms sounding.

So I will follow your suggestion and test the batteries -- with a Fluke 117 digital multi-meter that recently seduced me. 

Am I right in thinking that what you are proposing is something like the following?

Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 03, 2008, 07:09:49 AM
The battery charger discussion is here:,4338.msg25167.html#msg25167

It, too, is long and detailed.
Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 03, 2008, 07:12:12 AM

We do need a little time to make the charger decision, and it would be helpful to test to learn whether we could, meanwhile, use the old Flyback 20-3 charger without cooking the new 4D house batteries.

  • repeat until the batteries reach a voltage above which they do not rise or 14.1 volts, whichever is the higher and if it is 14.1 volts don't use the Flyback 20-3 any more at all

Michael, I think you got MOST of that right until the last one.  What you NEED to find out is how the Flyback works over extended periods of time and if it EVER drops down to a float charging level in the low 13.0 to 13.2 volt range AND ALSO whether it overcooks the banks when it FIRST STARTS UP if it goes over the bulk charging voltage range of 14.2 or so for MORE than 23 to 30 minutes.  THAT REGIMEN is what Calder, West Marine, Ample (do you have that yet?) and just about every battery charging expert recommends.  You also should record the specific gravity of each cell BEFORE and AFTER, since the batteries are or have been at rest by NOT charging them, you have a perfect opportunity to measure the cells and determine their condition.  Remember, it's BOTH voltage AND S.G. that are the measurements  for battery condition.

Given the information contained in this thread and the other one, I must admit to being somewhat perplexed about your inability to make a decision on the charger.  If it was my boat, I would do two things, today.  1.  Dis the Flyback.  Don't even bother testing it.  The INVESTMENT in your two new batteries do NOT warrant burning them up with the crappy charger.  A KNOWN CRAPPY charger.  Uh, how many times do we have to mention that?  2.  Buy a Truecharge 20 or 40, forgo further "investigation" of Truecharge 2's and XC's because, frankly, they are brand new and so far unproven and also have "features" that are or may not be applicable to your situation and uses.  As John noted, the Truecharge 20 and 40 are proven technology that have withstood the test of time. 

I would further suggest you consider investing in a Link 10 or 20 with the $$ you save on the charger.  Another important reason for this suggestion, repeated by many here to you, is that your "goal" for your boat and its four owners is to keep it simple.  Right?  Soooooooooo: Buy and install what is essentially a "battery fuel gage" and NO ONE in your group will EVER wonder about the battery conditions EVER AGAIN because they can simply read the gage.  Simple, huh?

I also believe that you may now have concluded that the CO alarm, which started this whole thread, can be attributed to the batteries being charged (or overcharged) by the Flyback nonsense.  Guess ya can put your propane back on the boat.  :D

Just my 2 cents.

And as always:   Your boat, your choices.[/list]
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 03, 2008, 11:10:00 AM

On further thought (and listening to you, albeit slightly selectively as you will see), I think we will not try to test the Flyback20-3 for even temporary use, although I appreciated the suggestion by Randy that we do so as an interim measure.  Your pointing out some of the complexities of testing the old charger made me conclude that the time spent testing it could be better spent elsewhere.

Here in Vancouver, the TrueCharge40+ costs about $400 and we can get the XC3012 for $425.  We are inclined towards the XC3012 even though it has not been around as many blocks as the TrueCharge40+.  The XC5012, at more than $600 seems overkill...or at least over what we would like to pay.  We are keeping in mind your suggestion, which we like, of getting a battery monitor like the Link 20.

The Xantrex dealer here has used the XC3012 for a year on his boat and loves it.

We recognise that our current system does not require the XC3012 but given the small price difference and the possibility that we will mix-and-match battery types in the future (e.g., using an AGM starter battery as Jon - I think it was Jon - does), the slightly more expensive XC3012 seems justifiable.  I recognise that the motivation here is urgency and that ad hominem arguments play a larger role than understanding on my part...but that may be the way this particular decision will play out.

Yes, I have the Ample link.

Regards, and again thanks.

Title: Re: Carbon monoxide (?) mystery
Post by: Jon Schneider on June 03, 2008, 01:18:26 PM
First, Michael, you get good karma for using "ad hominem" in a post.  Second, while I'm always wrong when I contradict Stu, I never learn my lesson, so here goes.  Since you have been able to leave your boat unplugged recently, I'm assuming that you don't leave the fridge on.  If you do, I think I would be tempted to spend the extra $50/owner for the Xantrex 5012, since I would also think there might be some quick turn-arounds where one owner has it for three days and someone else wants it the next day with nearly depleted batteries.  I think the extra 20 amps might help in that situation.  It also looks to me like the new Truecharge2 40 (it's only available in the same increments as the original Truecharge of 20 and 40 amps right now) actually is cheaper than the original Truecharge 40 (see  It'd be worth finding out from Xantrex if the new TC2 comes with a battery temp sensor and is able charge different chemistries (though, again, I don't think you will ever need this, and instead should charge the separate starter battery, when you get one, via a Duo Charge or similar combiner). 

I don't think you'd find that this new Truecharge "technology" is experimental or risky.  In fact, I'd bet that they're simply "sun-setting" the existing Truecharge technology and replacing it with similar increments of the XC platform (which don't exist in the current XC line).  So I'm betting that the TC2 is just the missing amperage increments of the existing XC platform.  And just to throw diesel on the fire, that'll mean that the old version Truecharge you buy today will be on life-support in terms of customer care in a couple of years, since by that time, it won't be "tested technology," but rather "obsolete technology." 

My one cent.
Title: Re: Carbon monoxide (?) mystery
Post by: tonywright on June 03, 2008, 03:01:25 PM
I am not sure that the XC is that new. The manual dates to August 2005.

It seems to have a number of desirable features, compared to the Truecharge 40:

1) It will charge the battery with the lowest charge first, rather than dividing the power as the Truecharge does. This should bring a dpleted battery bank up more quickly.

2) It provides better protection against overcharging at warmer temperatures than the 40 does.

3) The control and readout panel can be mounted anywhere. Since the normal location is in a hard to read location under the sink, this is probably a significant advantage for those who are feeling less athletic.

One interesting note is that both charger manuals warn about use of Modified Sine Wave generators (isn't the Honda 1000/2000 one of these?). Except that the 40 seems to have more of a problem with this than the XC.

If I was to replace the Charles on my boat, I would seriously consider the XC over the 40.


Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 03, 2008, 03:09:13 PM

You are correct that we do not leave Hali's refrigerator on.

I share your trepidation about taking a position contrary to Stu's good sense...and like you will probably continue to err sometimes.

More re: refrigerators.  Given the outpouring of argument in these threads in favour of cold beer, it is hard to resist concluding that, if the "unpluggers" are correct, beer (or anything else that would tend to keep refrigerators on and shore power plugged in) may be responsible for any number of sinkings, fires, explosions, etc.  My grandmother knew this to be true without needing evidence.

The Xantrex XC5012 battery charger is about $200-$225 more expensive here than the XC3012.  Although we Hali-ites are not too price sensitive, in the absence of a compelling argument (pace beer and refrigerators) for quick charging (and recalling from somewhere here that it is not the initial but the secondary or tertiary charging that takes most of the time), I am inclined to the XC3012, with the spare change saved in comparison with buying the XC5012 going towards a battery monitor, as Stu would recommend. (The Link 20 is about $400 here by one quote.)

At this point, it doesn't seem that we will be able to wait for the new TrueCharge2 line to be available although that line does seem to fill nicely the gaps in older lines of Xantrex battery chargers.

[Tony - thx for weighiing in.  Your post seen only after I posted the above.  The XC still seems to me to have some less than perfect features: for example, the optional intelligent shunt only monitors one of the battery banks; and the charging information on the XC monitor only relates to the battery being charged (although perhaps it is user-selectable).]

Title: Re: Carbon monoxide (?) mystery
Post by: Jon Schneider on June 03, 2008, 04:16:01 PM
Michael, those seem like sound reasons to go with the XC 3012.  That's what I have, but I figured four owners may stress the battery juice more than I, a single-hander, mostly day-sailor.  That said, so far, so good on the 3012.  I have it charging only my house bank, so I'm not sure about being able to monitor a second bank while it's charging another.  My 440AH four six-volt battery configuration is brand new, and I think the very first charging took two days to reach the float stage.  Now, after a couple of months, they accept are fully charged overnight, so the 3012 seems quite adequate, and hope it will be for you and your partners as well.  I haven't bought a Link monitor yet, but will soon (I think Stu gets a commission for every one sold to a C34 IA member... or should <wink>).  BTW (here comes a plug for my favor wire vendor), the factory-installed charger wire is probably woefully undersized.  I replaced it with #6 cable from  It's Pacer wire at the best price I've ever found, about two-thirds less than Defender or WM.  Be sure to remember to get the right-sized lugs/terminals as well. 
Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 03, 2008, 05:48:55 PM
Jon, NOT me!!!!  Ron;s the one among others, who for years have advocated getting the battery monitors first.  I set the procrastination record weith our Link 2000 - eight years.  Wrote it up in my Secretary's report in a recent Mainsheet.

Michael, please remember that you do NOT generally have to "worry" about your start (i.e.e, emergency back-up) bank, because unless someone leaves the 1-2-B on B, it'll always be there.  Charge it up, as John Nixon suggests, and leave it there.  If you use it to start the engine, it takes 2-5 amps - we've already HAD this conversation.  Charge it every once in awhile.

Buy the 30 A SC because a 50 A XC will still only put out what the house bank will acept, which is NOT, NOT, NOT gonna almost ever be 50 amps, or so it'll take a few more minutes to get the bulk charge phase done with, and BUY a LINK 10 and be done with it.  If you're NOT going to be changing battery types in the future, why the XC?  You could do what Jon S. has done and buy a Duo Charge later.  With your current 1-2-B switch you already have an emergency paralleling device.  OK, OK, I'll quit now...
Title: Re: Carbon monoxide (?) mystery
Post by: Randy and Mary Davison on June 03, 2008, 05:56:29 PM
Michael - let a day go buy and I'm out of sych with the thread!

You're on a good course to bag testing and buy a good charger.  The pain in your wallet will be short lived and your batteries will love you for it for years.

To tie up the thread on testing - Stu said it right.  What you're testing for is how the charger manages the batteries, not what they look like after the charge.  The test is to turn the charger on and see what voltage it settles on for final float (per the voltages given earlier).  If you can be at the boat, his idea of looking at the voltage during the bulk charge isn't a bad idea although any battery will be able to handle short term, high (up to 14.5v) voltages.  What cooks batteries is a high float that boils off water until the plates are uncovered or generates high levels of heat with overcharge.  BTW, the Fluke meter is a good choice!  I'm biased by working there for almost 30 years until 2001.

Also to complete a thought in the thread - putting the charger in with the batteries is how I "proved" it was the battery gasses.  Only takes a minute in the enclosed space to sound the alert.

Finally, I leave the charger on durinng the much of the year.  We have power on the boat all winter for heaters and dehumidifiers and in the summer to run the fridge.  Boats sink because of leaks too and I like to have long term power for the bilge pump.  I suspect this is a religious type discussion like anchors and anchoring which can be argued with merit on both sides.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 03, 2008, 07:34:56 PM

1.  But you do love your battery monitor now.  It shows despite your denial to Jon.

2.  Perhaps we should change the name of this thread to "Carbon monoxide (?) mystery and battery charging issues" as we revert to the battery issues continually.  (Indeed, yes, I think the carbon monoxide and propane issues are now pretty much dead...and the propane can has gone back aboard.  The ladies needed it for tea this weekend.)

3.  A first cut at Hali's energy budget gives me 325 Ah available (not including charging off the engine or anything from the starting battery), daysail usage of 59 Ah, overnight usage of 89 Ah, and "at sea" usage of 205 Ah.

4.  Those figures - they require some shoving around and accept some of your figures without customizing them for Hali - make me also keen on a battery monitor.

5.  As far as I can tell (which is probably not the wisest thing to say in the circumstances), Hali's 1-2-B switch does not connect to the starting battery bank at all.  The starting battery, located aft of the stuffing box, has its own On-Off switch in the aft cabin.  We never run the battery selector switch on B.  Even days of the month, we select house battery #1.  Odd days of the month we select house battery #2.

6.  Given this configuration of Hali's batteries, would you be inclined to change your recommendation of a Link 10 instead of Link 20 battery monitor, Stu?  My understanding is that the Link 10 will monitor one battery (or battery bank) whereas the Link 20 will monitor two batteries (or two battery banks).  My preference for the Link 20 is that it would monitor individually both of Hali's house batteries, and that would accord with the way we use those batteries separately and with the way they are "banked" separately.  From what you said above, I infer that you were thinking that the two house batteries would be treated as one bank for monitoring purposes, so a Link 10 that monitors only one battery or battery bank would be enough to monitor those batteries (and there would be no need to monitor the starting battery).


7.   I'm glad the Fluke was a good choice...and hope some of the purchase price goes towards your pension plan!

8.   We will probably watch the new charger in action as you describe.

9.   We haven't charged the batteries for days now, so haven't had an opportunity to test their gas discharge with the CO monitor.  It will be interesting to see whether a new charger also causes the batteries to tickle the monitors.

10.  Like you, we run heaters (or at least dry-stor fans) in the winter, so we will keep Hali plugged in during the winter.  Perhaps to plug or not to plug is also a seasonal thing.

Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 03, 2008, 11:00:09 PM
Michael - had we not separated the threads we'd've set a new record for pages ona single thread!   :D

5 & 6 - Separate start bank with a split bank, while not new, is very unusual on C34s.  All I can suggest again is to go to Calder and read his discussion which recommends as large a house bank as possible and why.  I've copied that text here at least two or three times.  I'll see if I can find it again if it wasn't in my previous reference links.  See reply #8 here:,973.0.html  

Consider combining your two start banks into one big house bank and get a Link 10.
Title: Re: Carbon monoxide (?) mystery
Post by: Mike Vaccaro on June 04, 2008, 05:50:13 AM
One point to ponder that I don't believe has been discussed in a bit...

The rule-of-thumb for calculating requirements is that the charger needs to be capable of delivering at least 6.6% of the total bank capacity in amps.  Thus, for a 440 amp bank (the typical four golf-cart 6V battery option
on the C34), a charger should be capable of delivering at least 29 amps to that bank.  Wiring from the charger to the batteries should be properly sized to ensure no more than a 5% drop (less is better, i.e., it's O.K. to over-size the wiring).  An appropriately sized fuse or circuit breaker should be installed to protect this circuit.

Another point to ponder is that the charger becomes the DC power supply when the boat is plugged in or another source of AC power is available.  Most of us tend to use electricity rather frivolously when we have an unlimited supply, but it's still possible to over-tax the system if your charger is undersized.  The best way to keep track of charger output and battery status is to be able to reliably monitor the system.  The most convenient way to do this is to install some type of battery monitor.   

Matching the charger to the system is important.  By operating an undersized charger, it ends up working too hard and like many things electrical, heat turns into the enemy, shortening the life of the equipment.  The usual tendency is to increase battery capacity, but tie into existing wiring or charging systems which may or may not be up to the task.



Title: Charger Right-Sizing
Post by: Jon Schneider on June 04, 2008, 07:15:45 AM
Mike, that's a great point about taxing the charger too much and thus creating heat and wear.  I hadn't really thought about that before.  BTW, where'd you come up with the 6.6% statistic?  I have to say that I too have the "typical 6-volt 440AH configuration" (damn, my momma didn't raise me to be typical), and I certainly haven't had a chance to stress the grid yet, but after a day's sail with fridge and energy-consuming below-decks autopilot, I haven't seen the XC 3012 go above 23 amps output.  Now, that may be because like all chargers, it's not capable of really maxing out at 30 amps (though I doubt it), but I suspect it's more about battery acceptance and need.  The charger hits the next stage (absorb?) within a couple of hours under that scenario.  So far, the only smell of smoke is coming from my cheap cigars ;)
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 04, 2008, 09:27:37 AM
Stu, thank you for Nigel Calder's "one big house bank" article...and for a particular thought that it led to.

Calder's article makes the point that battery longevity increases when batteries are discharged less on each cycle.  Therefore, the argument (from lots of points of view: economy, ecology, saving the pinkies when changing batteries less frequently,etc....) is to combine the house batteries in the biggest bank possible.

But is there, I wondered, an argument to be made in favour of not combining the batteries in order to maintain the redundancy that separated battery banks provide?  By creating one big house bank, are we putting all our eggs in one basket?  (If so, I see that the discussion could take on something of the flavour of the "plugger/unplugger" debate, with people coming to different conclusions depending on how they relate to safety, convenience, risk, etc.)

Does having a battery monitor alleviate your concern, Stu, that there will be a bank robbery of the "one big bank"?

Asking these questions led me to question whether having redundant house battery power is really an essential virtue.  In a pinch, without house batteries, we can raise the anchor by hand, eat steak before the fridge thaws, helm instead of autopilot, conn without GPS, talk on a handlheld instead of a fixed radio...

All that looked fine, until...nav lights.  On my little Vivacity, which has a sketchy electrical system, we have always carried oil lamps for navigation in case the electrical system failed; but on Hali, oil lamps weren't even on our To Get list until your reference to Nigel Calder's article triggered this line of thought, Stu.

Pending feedback from the message board, my conclusion is that for Hali a single big battery bank would be fine, if we get a battery monitor and backup oil navigation lamps.  (If Hali had radar, I would want a redundant house battery.)


Hali's house bank capacity, at 325Ah, is well shy of the 440Ah norm that has been mentioned.  Assuming we can live with that battery capacity...and perhaps it is not so difficult to do here in the NW where we do not need air conditioners and the refrigerator does not need to work too hard...the 30 amp Xantrex XC3012 battery charger we have been discussing should have no trouble charging the house batteries beyond the 6.6% of capacity you mentioned, even at the 23 amp rate that Jon has noticed.

Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 06, 2008, 11:45:57 PM
Michael, the third of the three reference links in Reply #17 in the (separated) Battery Charging Techniques thread covered the answer to your question about split house banks compared to one larger one:,1208.15.html (,1208.15.html), see Reply #16.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 24, 2008, 12:33:04 AM
At the end of the long and winding road, a summary of our conclusions about the problems and a statement of what we did aboard Hali to sort them out might be in order.

To get where we are, we relied on help from this thread and related threads more often than it is possible to give credits for.

Many thanks to all of you.

1.  the propane monitor and carbon monoxide monitors aboard Hali were being triggered by hydrogen boiled off the new house batteries during charging by the old Flyback 20-3 battery charger.  We could not make any other theory fit all the known facts.  However, if the propane or carbon monoxide detector goes off again, we will try not to assume we know why.

2.   the battery charger might have been working overtime because of higher-than-necessary demands for electricity caused by unnecessary cycling of the bilge pump.  Solving the bilge pump cycling problem became important.

3.   the bilge pump was cycling on too often because we didn't do a good job of packing the stuffing box last summer: the stuffing box, both at rest and when the propeller shaft was engaged, was throwing off too much water.

4.   following Ron's advice, we re-packed the stuffing box with dripless Goretex GFO.  It took two attempts for us to get the nut-tghtening just right:  the secret seems to be to tighten the large nut barely hand tight, at least at first (although the retaining nut needs to be tight).  The bilge now stays virtually dry: water rarely covers even the bottom surface and never (so far) reaches a level high enough to activate the bilge pump.  A corollary benefit is that the keel bolts may have stopped rusting.

5.   following Ron Hill and Jon Schneider's advice here, we installed two (plastic) vents into the below-settee battery containing space, one facing forward and one facing athwartships.  Whether this will keep the concentration of hydrogen gas below Randy Davison's explosive proportions, remains to be seen.  As Stu Jackson pointed out, it might just help escape the gas to activate the alarms -- good deeds rarely go unpunished.

6.   we have held off installing Tony Wright's solar ventilator in the hatch.  Its on our "maybe" list.

7.    following advice from here and other threads, we junked the Alltech Flyback 20-3 battery charger...and are glad of it.

8.   going out on a limb, albeit following Jon's lead but before getting the comfort of John Nixon's cautious approval of the Xantrex XC3012 battery charger, we bought one.  It passed Mike Vaccaro's 6.6% test, even if we boost Hali's housebank to the more usual 440 amp hours size.  And it alternates in charging our two battery banks so quickly (about every 15 seconds according to the user manual) that there is no grounds for my previous apprehension that information about the charging of more than one battery bank would not be readily available on the charger panel.  We located the remote control/monitor panel where it can be easily seen, beside the chart table.

9.  we have started a battery log and are recording terminal voltages, the specific gravity of the fluid in each battery cell, and when we top up the cells with fluid.  This data collection is running ahead of our understanding, but the data will be there for later.

10.  we changed from using one house battery at a time to using both house batteries at a time by the simple expedient of selecting "Both" on our battery selector switch instead of 1 or 2.  But based on what was written by Stu Jackson (to whom we owe the information that led to this change), Hali's battery configuration is a bit unusual (two small house batteries treated separately and the separate starting battery not linked to the main battery selector switch) so this easy solution might not work for many others.

11.  we charge both house batteries separately, to take advantage of the ability of the Xantrex XC3012 to charge up to three separate batteries or banks of batteries.

12.  we haven't yet bitten the bullet and bought a battery monitor, but one is on the wish list.

13.  Our actual power use remains unknown, but we have taken a first crack at preparing an energy budget.

14.  Mike recommended installing a fuse or circuit breaker between the new charger and the battery.  Xantrex makes a similar recommendation.  We haven't done it yet.  My reading of the Xantrex user manual leads me to believe that the purpose of the fuse or circuit breaker is to prevent the wire (from charger to battery) from burning out if overloaded.  We are using 0/1 wire.  There was never a fuse or breaker in the old configuration.  Does Mike or anyone know more about this?

15.  we bought a magnifying glass, for use on charts and to go with the deer stalker.

Problems paired up and climbed onto the ark together.  The sounding of the alarms initially led in many directions.  Even when resolved into one direction, the line led from alarms to batteries to battery charger to bilge pump to stuffing box.

Title: Re: Carbon monoxide (?) mystery
Post by: Jon Schneider on June 24, 2008, 05:12:45 AM
14.  Mike recommended installing a fuse or circuit breaker between the new charger and the battery.  Xantrex makes a similar recommendation.  We haven't done it yet.  My reading of the Xantrex user manual leads me to believe that the purpose of the fuse or circuit breaker is to prevent the wire (from charger to battery) from burning out if overloaded.  We are using 0/1 wire.  There was never a fuse or breaker in the old configuration.  Does Mike or anyone know more about this?

Ah, I had the same issue, and decided to follow Xantrex's advice but had also figured that the fuses would be better placed adjacent to the charger (versus near the batteries... we had a discussion on the board about this back in the spring).  I eventually came around to reason and placed the fuses near the battery-end of the charger cable.  You're right that the reason for the fuse/breaker is generally to protect the wire first, but it also protects the equipment.  That's why I always install a breaker sized to whichever is smaller, the line requirement or the equipment safety.  Here's the reason why I fused the circuit between the battery and the charger: While I recall that there is an internal breaker in the Xantrex unit which should protect it, it is not user-serviceable.  Therefore, I don't ever want to trip it (and frankly I don't trust anything I can't see and fully understand from a schematic POV).  If the internal breaker did trip, that would mean that I would probably have to send the unit to a warranty center, and it would probably be out of service for weeks.  That's something I obviously want to avoid. 

BTW, you mention 1/0 cable.  Really?  I thought I was the king of over-sized wiring, but that is some pipe you put in.  How long's the run?  Was that the original cable that came with the boat when you bought it?
Title: Re: Carbon monoxide (?) mystery
Post by: tonywright on June 24, 2008, 07:26:27 AM
That was my reaction to the 0/1 too Jon. The stock wire on mine is probably 12 or 10. I did note that Xantrex recommends 4 or 6, which appears to be tied to the amounts of amps it can produce.  I would imagine that it would be hard to wire a fuse in line to 0/1. Like Michael, I am very much in learning mode on this.

On the subject of identifying the gas that set off the alarm, I asked my neighbour, who is a fire chief, whether the fire dept had the necessary equipment, and whether they would have come to test had you asked. His reply was very affirmative. They would far rather help you avoid a problem, than come out after something serious happened. A fire dept in a large city is almost certain to have the necessary test equipment to identify the gas involved. Worth remembering. (I am sure that Aunt Gertrude would approve.)


Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 25, 2008, 05:57:34 PM

Hali came equipped to us with the heavy (1/0 gauge) wires between the battery charger and the batteries.   The cable runs are less than six feet, from the charger beneath the built-in garbage can to the battery boxes beneath the aft settee in the salon.  My hunch was that any possible power draw (from charger to battery or vice versa) could not exceed the rating for that wire, so there would be no fire hazard if we dispensed with fuses or circuit breakers.

But doubting my hunches might be good policy:  I blew a fuse on my new Fluke multimeter last week.

Yours is an interesting point, Jon, that the other purpose of the fuse or circuit breaker is to protect the Xantrex XC3012 itself from, I suppose, a surge of power from the batteries.

For what its worth, a posting in an electric vehicle discussion (at on a Google search and of unknown authority), indicates that 1/0 gauge wire is rated to support up to 120 amperes in a cable run of 120 feet at 60 degrees centigrade with a 1-3% drop in voltage.

Am I correct in thinking that in calculating the possibility that a surge of power from the batteries might overheat the wire or damage the XC3012, we would assume the possibility of a dead short drawing the maximum current over a short period of time through the wire and into the battery charger?  And therefore, that we could look to some short term output rating (cold cranking amps?) for the batteries (flooded lead acid Interstate 4Ds) to determine whether the wire rating or amp rating for the battery charger might be exceeded?

Now that I begin trying to figure this out, it begins to seem like a better and better idea just to follow the Xantrex suggestion and put a fuse or circuit breaker into the lines.  Do you think that I would be right in taking the Xantrex XC3012 30 amp rating as the appropriate figure and using a 30 amp circuit breaker? [Later edit: no.  See Jim Moe tech note cited by Stu Jackson at post #62 below and see post #63.] (It seems to me that that the rating for the 1/0 gauge wire being substantially higher, the "weak link" would be the battery charger itself and that the circuit breaker should therefore be selected with protection of the battery charger in mind.) The slithering sound you hear is me skating here.


Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 25, 2008, 06:23:06 PM
Michael, why not keep it simple and not reinvent the wheel.  Jim Moe's electrical system design, here:  discusses the ABYC fuse requiremens and includes sizing for your application.  It could also be that your charger installation manual includes that requirement - our Freedom 15 I/C did.
Title: Re: Carbon monoxide (?) mystery
Post by: Michael on June 25, 2008, 09:40:45 PM
Stu, thank you for the reference to Jim Moe's article.  From that article, which touches on all sorts of good things, I take away relevant to the current situation that:

(1) fuses should be rated at 150% of the charger capacity [which I think but will check will mean a 45 amp fuse for the XC3012];
(2) the fuses can be conveniently located in the battery box; and
(3) the AYBC code requires the fuses.

Conclusion: we will install fuses (or circuit breakers) in the battery compartment on the charger-to-battery cable runs.

Title: Re: Carbon monoxide (?) mystery
Post by: Stu Jackson on June 25, 2008, 10:50:37 PM
1.  Sounds about right
2.  It's not convenience in the battery box, but rather within 7 inches of the battery which si the rule
3.  yup, although many of us have lived for years without them, before the newer codes came into effect  -  I believe I covered that subject, of newer codes, in earlier discussions
Title: Re: Carbon monoxide (?) mystery
Post by: Jon Schneider on June 26, 2008, 05:34:59 AM
FWIW, Michael, I came to the same conclusion you have, and installed 40A fuses in the battery case for the XC3012.  Technically less that the 150% rule, but close enough (I don't think there's any such thing as a 45A fuse), plus the tripping action is probably at least 10-20% higher than the rating.  Don't forget to buy back-up fuses.