Battery ratings MCA

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KenAyer

I need to replace the 2 Exide Nautilus 4D (?) batterries in my 2002 C34 MKII.  The originals say they are "1400 MCA and have 400 minute reserve power" & are "dual starting/deep cycle".  The current replacements from Exide wouldn't fit the available space.  It seems like the originals were much more powerful than is necessary.  Posts under "batteries" don't list the MCA, which I thought was the critical number for starting power.  Would 2 Group 27 (745 MCA) or Group 24 (650 MCA) work OK?  I do mostly day sailing and occasional cruising on San Francisco Bay, so don't lay up for the winter. 

Jon Schneider

I'm not clear if you're thinking of replacing each 4D with two 27s or 24s, but if you're thinking of replacing both 4Ds with only two 27s or 24s, I think you're short changing your system a bit.  At the very least, I would recommend all 27s, and I would have three at least with one configured as one the starting battery.  To your question if ~700 MCAs is enough, the answer is yes, especially if you've done the solenoid trick on the glow plugs (though I'm not sure if this is necessary on a 2002 Mk II).  If you sail frequently and can remember to switch banks for starting, then I would recommend four 27s configured into two equal banks.  Alternate using one bank as a starting bank (i.e., let it rest from house duties) every other time.  Some frequent sailors use odd/even dates to dictate which bank gets used on any particular day (e.g., bank one on odd days and bank two on even days). 
Jon Schneider
s/v Atlantic Rose #1058 (1990)
Greenport, NY USA

Stu Jackson

Jon, what happens in leap years?   :?
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Jon Schneider

You replace the batteries, Stu.  :idea:
Jon Schneider
s/v Atlantic Rose #1058 (1990)
Greenport, NY USA

Stu Jackson

What a great concept, now all I have to do is get them to work so I can go every TWO Leap Years! :clap
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Jon Schneider

I'm counting on John Nixon's AC-to-DC power supply approach for my fridge doing just that.  Just completed the project a couple of weeks ago (by nagging him nearly as much as I nagged Stu during my 12v upgrade this spring).  It's so fantastic to have chilled vodka (kept in the freezer) when I arrive at the boat (not that I drink it... it's just a comforting feeling) and know that I haven't stressed the batteries to do so.   8)
Jon Schneider
s/v Atlantic Rose #1058 (1990)
Greenport, NY USA

Bill Asbury

I understand your interest in keeping vodka chilled, Jon, especially if it's the cheap stuff, which like bad wine probably tastes better cold; e.g., sangria.  I keep my mellow Mount Gay rum and good red wine in a galley drawer, but keep the fridge on to keep the mixer chilled (grapefruit or orange juice).  Also beer and wine (the cheap stuff---Corbett Canyon Chard in the box at $9.99 for three liters).

Had a galvanic isolator installed because of electrolysis on my max-prop observed at haulout in May.  Previously kept plugged in to shore power much of the time over the past 14 years without trouble.  Am aware of the ongoing debate on this board whether to plug or unplug with the consensus apparently favoring the unplugged side of the issue, but my tech, a former Navy engineer whom I respect said I can stay plugged in without causing a battery overcharging problem, etc. due to the way my system is set up.

Would appreciate your thoughts/humorous comments on the above.

Thanks,

Bill 

Bill & Penne
Sanderling 2005 C34MKII 1686
Chesapeake Bay

Jon Schneider

Cheap stuff!!! Them's fightin' words.  Vodka needs to be on ice otherwise it's either not cold enough or, if on the rocks, the rocks will dissolve and dilute the vodka. 

Regarding staying plugged in, I don't think we really have enough info about your system to determine if you're liable to overcharge your batteries.  Do you have a charger that's capable of zero output? 
Jon Schneider
s/v Atlantic Rose #1058 (1990)
Greenport, NY USA

Roc

Ken,
I don't understand why the new 4D's won't fit in the existing compartment.  I thought if a battery is a '4D' it has certain dimensions related to it.  There seems to be enough room there even if the dimensions change by a small amount.  Are the new ones that far off?
Roc - "Sea Life" 2000 MKII #1477.  Annapolis, MD

Stu Jackson

#9
We might have gone off topic a bit, but the vodka sure was good, cold and all!

Just FYI, here's the text of the material Dave Davis and I forwarded to Ken offline, which is what got Ken to post his question here.  I'm doing this to avoid repeat input, and generate even more discussion and ideas for Ken.

Ken,

Dave's right about the source of getting information.

Using combination start / deep cycle batteries is not a preferred solution.  I recommend that you consider a large house bank by combining your two large batteries and installing a second smaller "emergency reserve" (sometimes called a "start") battery.  The CCA and MCA of house batteries are meaningless, you need as many amp hours as you can get.  For the emergency reserve battery, a simple automotive brand of about 50 to 60 AH is all you need.

In addition to Dave's link, try the C34 Website Projects page (http://www.c34.org/projects/projects.html) and look at the Electrical Systems Upgrade article, especially this one:  http://www.c34.org/projects/projects-electrical-system-upgrade-2.html and this one: http://www.c34.org/projects/projects-battery-selection.html

There is no ONE "right" way to do it, and you have to decide how you use your boat (marina hopper or anchor out, for instance) to determine what's right for you.

Your boat, your choice.

Best regards,

Stu

In a message dated 8/13/2008 8:36:23 A.M. Pacific Daylight Time, davis_707@yahoo.com writes:

Ken, I'm not familiar with the type batters that you are using. I would suggest you send out your problem on the the Catalina Message board.  www.c34.org/bbs There has been lots of information about batteries on their search.   FRI I am using 4,  6 volt 200 amp. I am on my 10th year and have been real good. The type of charger and how you use the charger is a big part of the battery life. You are welcome to take a look at mine anytime.
Good Luck, Dave

Ken

It also occurred to me that it might be helpful for you to read the West Marine Catalog, Electrical section.  They have much good information on batteries and systems, and like our C34 website, it's all free.  You could also not go wrong in buying Nigel Calder's Boatowner's Manual for Mechanical and Electrical Systems, a worthy $50 investment in your boat.

Stu

Ken

And when you do get your new batteries, I recommend that it is critical that you read this:  http://www.amplepower.com/primer/
We got our wet cell batteries in Hayward, American Battery Company, right from the distributor, great price, 30% cheaper than West Marine.  Do NOT buy from West Marine, you'll just get ripped off.

Stu

I also bought my batteries from America Battery Co in Hayward. Jim is a nice guy to work with. He owns the place and has a huge information bank.. He also made me an extra grounding cable and a hydrometer at no extra $.

Dave 
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Bill Asbury

Sorry, Jon, not being a vodka drinker I didn't know it has to be kept chilled.  Regarding electrical systems, my ignorance is about equal to my vodka expertise, if not moreso.  I have a Zantrex Truecharge 20 which my tech advises me won't cause overcharging from being plugged in.

Thanks for your interst and for taking time to respond.

Kind regards,

Bill

PS - I'll go to the boat tomorrow and put the cheap vodka (for guests) in the fridge.  Should I also chill the cheap gin I have on board?
Bill & Penne
Sanderling 2005 C34MKII 1686
Chesapeake Bay

Ron Hill

#11
Guys : The bit about staying plugged in if you have a smart charger (3 stages) with the fridge turned ON is NOT so much about hurting the batteries.  The smart charger should take care of the batteries, but it's about the wear and tear on the fridge unit and that charger.  The charger is constantly sensing and charging/turning off.  There is also the real threat of a lightening power surge when plugged in (and not being on the boat).  Although it is not good to keep lead acid batteries at full charge all of the time, as you are also unnecessarily wearing out batteries, charger and the fridge.

It would seems to me that with an insulated bag you could put in you frozen vodka, gin or what ever booze from home and pop it open on the boat and save all of that wear and tear on the boats systems for the 6 or what ever # of days till you get back to your boat!!   A thought.
Ron, Apache #788

Bill Asbury

Thanks, Ron.  I've owned sailboats for 17 years without experiencing a lightning strike on or anywhere near my boats, so either the odds are highly in favor of not being hit or it's just a matter of time until...

Regarding the charger and batteries, it makes sense that the useful life of the charger might be shortened if it is constantly cycling on and off but I don't understand batteries well enough to know why it would be a problem to keep them fully charged while in the slip awaiting the next cruise.  Perhaps you could enlighten me on that point.

BTW, I'm retired now and the marina is just a few blocks from the house so I visit the boat to do maintenance or just mess around about every other day on average, and it's nice to have cold drinks handy on these hot summer days, plus operating various electrical gadgets as needed.  The Admiral on the other hand has a busy schedule so planning cruises ahead is a non-starter, which is another reason why I like to keep the batteries topped up and the fridge cold.

Thanks again for taking time to post your comments.

Bill 
Bill & Penne
Sanderling 2005 C34MKII 1686
Chesapeake Bay

Jon Schneider

Quote from: asbury on August 15, 2008, 03:10:06 PM
PS - I'll go to the boat tomorrow and put the cheap vodka (for guests) in the fridge.  Should I also chill the cheap gin I have on board?

Absolutely (no pun intended) chill the gin.  I keep gin, vodka, and vermouth in the freezer with a bag of ice on top of them.  The only problem is that your guests may stay longer and come back more frequently.
Jon Schneider
s/v Atlantic Rose #1058 (1990)
Greenport, NY USA

Jon Schneider

Quote from: Ron Hill on August 15, 2008, 05:44:05 PM
Guys : The bit about staying plugged in if you have a smart charger (3 stages) with the fridge turned ON is NOT so much about hurting the batteries.  The smart charger should take care of the batteries, but it's about the wear and tear on the fridge unit and that charger. 

Wrong!  It is all about wear and tear on the batteries.  Constant use of the fridge via the batteries means that the sulfation process is occurring constantly even if you have a so-called "smart charger."  Certain smart chargers (see John Nixon's brilliant evaluation of TrueCharger vs Xantrex XC chargers) actually don't constantly pump in low amp levels (XC models for sure don't).  Nevertheless, constant use of your batteries will decrease the life of your batteries no matter what charger you have.  Install John Nixon's ac-to-dc power source for your fridge if you're going to keep your fridge on all the time while shorepower is available. 
Jon Schneider
s/v Atlantic Rose #1058 (1990)
Greenport, NY USA