Battery Charging Techniques

[Joe Kern]

I am a plugger too, but don't keep the charger on.  Our a/c has a great anti-humidity feature but the power has to remain on.  On my previous boat mold and odor was a constant problem, but on this boat everything stays clean and odor free.  Not an easy trick in Florida.

I know there is some risk leaving her plugged in and having one thru-hull stay open, but the liveaboards on the next slip keep an eye on her and we are there at least once a week.

Joe

[Michael]

Does anyone have experience with what is apparently a new Xantrex offering, the XC, which one of Hali's co-owners, in discussion with a local marine supply shop owner, has had recommended to us as an updated and "smarter" version of the Xantrex Truecharge 40 battery charger?

[Stu Jackson]

PRUDENT INVESTMENTS  [Stu Battery System]

Michael,

I just looked at the XC chargers.  The 25A model is $689 US.  The 30A is $485 in the WM 2008 catalog.

I also just received a flyer from WM with the Truecharge 20+ at $300 and the 40+ at $400.

I think the question you have to ask yourself is "What do I need and do I have to spend more than what I need?"

The XC permits charging multiple banks, as does the Truechargers.  It permits the mixing of battery types.  Do you need to do that?  Will you ever do that?  The XCs include a remote OPTIONAL shunt, but YOU have to decide what you want to employ for your use for a real battery monitor.  Your choices are the Link series or Xantrex's newer "gages."

I personally believe the XC is overkill, given what you describe as your electrical system.  That said, if I recall correctly, you just have the two house batteries separated into two separate banks, with plans for a separate start bank.

What we did when we bought Aquavite in 1998 was to do a complete cost comparison of different systems available at the time.  We KNEW we wanted an inverter because the PO had installed a microwave.  I knew the size of the house bank so I could properly size a charger.  I knew we would eventually upgrade our OEM alternator, and studied what I could do with single source chargers, because so many of the good chargers come with multiple outputs, but the alternator only has one (unless you do what Ron Hill did and get a dual output alternator).  I priced separate chargers and inverters, combined ICs (like the Freedom 15 we bought) and various battery gages (Link 10, 20 and the Link 2000 we bought because it controls the Freedom 15).  We installed a 130A combiner, overkill for our old OEM alternator, but we knew we were going to upgrade the alternator, so when we did it in 2006 we didn't need to replace the combiner (see Nov 2006 Mainsheet Tech Notes report).  I've installed a shutoff switch on the combiner to avoid overcharging the start bank when long motoring sessions are required.  The Freedom has a single charging output (because the same heavy wiring is used for the inverter side), so had the challenge of learning early on what single source charging means and how to deal with it, because so many people used the multiple outputs of the chargers, but then still were forced to have the alternator output go to the C post of the switch.

I strongly urge you to think ahead about what you want to do and what will best support your needs, and design a SYSTEM that will work for all of your proposed boat uses.  If your boat companions like to dock (marina - hop) then a simple charger is all that you'll ever need.  If you, however, like to anchor out, then you need to start thinking about combining your two 4Ds, adding a separate start bank, increasing your alternator with a new regulator and just finding a decent charger without all the bells and whistles you'll probably never need.

If it was my boat, here's what I'd do:

1.  Do the separate start battery and combine the 2 4Ds
2.  This will permit you to buy only a Link 10 to monitor the house bank, rather than both.  Your choice to get a Link 20 if you want to monitor both banks
3.  Get a Truecharge, the XC is overkill UNLESS you plan to mix battery types in the future (AGM start bank, wet cells or gels for house)
4.  In order to decide how to wire your charger (i.e., multiple outputs to separate banks or single output to a PDP) think about how you have your alternator output wired.  It most likely goes to the C post of the 1-2-B switch.  I've discussed this many times before.  Try this:  http://c34.org/bbs/index.php/topic,2977.0.html.  Also click on the link in one of my posts to the longer earlier thread which discusses bigger, biggest house banks (this one: http://c34.org/bbs/index.php/topic,2347.0.html).  Here's another good one: http://c34.org/bbs/index.php/topic,1208.15.html
5.  Consider your alternator and decide if you want to upgrade - this could come later, but will force you to think now about future wiring

You could also just jump to Item 3 and save the rest for later.

[Jon Schneider]

Michael, I have a Xantrex XC3012.  It's just fine, but I agree with Stu's assessment.  I bought the XC series because I knew I was going to install an AGM starting battery (AGM because I knew I was going to install it next to the shaft, and I didn't want to service it).  So, I thought I needed to be able to charge my flooded cell house bank and my AGM from the shore charger.  But then, since I wanted to be able to charge my start bank from the alternator as well, I discovered the Balmar Duo Charge which drip charges (up to 30 amps) the different chemistry start bank from the house bank.  If I had to do it over again, I would go with the TrueCharge 40, since there is no reason to keep my starter battery on the charger all the time.  It actually never needs any further charging other than what the alternator supplies via the house bank/Duo Charge.  As Stu says, however, you gotta figure out the whole system, and then buy the components. 

[Michael]

Stu and Jon, you two have given us Hali-ites lots to think about.  Thank you for putting so much into your messages.

Nothing I say in this message [which has been further amended since first posting] is intended to suggest that I have thought my way through what you have posted, but doing so may require more reading and thinking than I can do immediately.  Meanwhile, I will give a bit more "Hali-specific" information that might fill out the picture.

Currently, Hali has the two new deep cycle marine/rv wet cell 4Ds (with a 1-2-Both switch) and one (new last year) wet cell starting battery. 

Every one of the new 4Ds cells were found yesterday (May 29) to be low on fluid.  Interstate (the battery manufacturer) recommended that we top up the cells with distilled water and not with more sulphuric acid, so we did that.  We used just over 3 liters of water over the 12 cells, with each getting about the same amount, I think.  As mentioned previously, other than one cell, unfortunately we had not checked the fluid levels when we installed the new batteries on May 13.  Yesterday, the electrical panel analogue voltmeters measured one of the new 4D batteries at 12 volts, but my new Fluke 117 multi-meter measured it at 13 volts. (Stu, this seems reasonable vindication of your doubt about the accuracy of analogue voltmeters!)

I don't know what kind of alternator Hali has.  She is out tonight, so I can't check.  (As you will have no trouble gleaning, the electrical system -- except the starting-glow plugs-fuel pump circuit that we had a long thread about last year - is not something I have much worked on since we got Hali in March, 2007.)

The Flyback 20-3 charger aboard Hali is now turned off and, I suspect, will never be turned on again. (We are beginning the "new battery charger" debate.)  Hali is not plugged in today. (We are listening to the plugger-unplugger debate here with interest.)

Three of Hali's four owners live or work within five minutes drive of Hali...so we can check on her often and do, at least in summer.  From May through September, one of us probably visits Hali at least every other day.  From October through April, once a week might be the norm.  The marina is small, without a lot of people about, so that, except in summer, we couldn't count on anyone else observing anything wrong at Hali within time to do anything about it. 

One of our owners works in a stationary diesel supply business and so has access, in case of urgency, to good technical help...but this probably does not extend to system design.

As a result of having four owners to pay for things, we are not too fussed about the cost of things.  As between quality and price, we would usually decide on quality.  With four sets of owners, we also value up-time and not having to do a repair again soon.

One of my co-owners and I are do-it-yourselfers.  The other two co-owners are not generally involved in maintenance.  We only involve professionals for things we DIYers really can't do ourselves. (This doesn't mean we are qualified...just somewhat persistent, time allowing.)

On the straight TruePower 40 versus XC question, my buddy who designs power supply systems got back to me.  His response (and it may be only the first in a longer dialogue) was, I think, from the system perspective without considering, as you have recommended, Stu, our specific needs and intentions for Hali, which I did not tell him about.  He wrote:  "The new one [XC] is better.   Consider 50 amp version.  You need extra temperature sensors (it comes with one you should have one per battery).  There is an optional 'intelligent shunt' that will allow you to monitor usage."

Regards.

[David Sanner]

It's about time someone mentioned keeping their beer cold, especially since many use use their boat a support to keep their bbq above water.

I stay plugged in and keep my batteries from being undercharged though I don't equalize them as much as I should.   What about those hi-freq pluse add-ons that are suppose to help with sulfates?

[Jon Schneider]

Dave, I bought one of those pulsers last year for some pretty dead batteries.  My charger at the time (17 years old, can't remember the manufacturer) wasn't capable of producing an equalization charge, so I put the pulser on a single flooded-cell deep-cycle group 27 which I used as a starting battery.  It didn't have any effect so far as I could tell.

[Stu Jackson]

On the straight TruePower 40 versus XC question, my buddy who designs power supply systems got back to me.  His response (and it may be only the first in a longer dialogue) was, I think, from the system perspective without considering, as you have recommended, Stu, our specific needs and intentions for Hali, which I did not tell him about.  He wrote:  "The new one [XC] is better.   Consider 50 amp version.  You need extra temperature sensors (it comes with one you should have one per battery).  There is an optional 'intelligent shunt' that will allow you to monitor usage."

Michael,

As Jon mentioned, the XC is "better" but for what?  If cost is no object, sure, go ahead and buy something you really do not need.  Many wish they were in that position.

But what I'd like to do, in lieu of retyping what's already been published in books and written about here in great detail over the course of the last few years, is to steer you in the right direction and give you references for you to make your own decisions.

1.  Charger Sizing:  As far as sizing, if I recall, you said you do have Calder's Boatowner's Manual book.  If it's the Second Edition, look on page 165, or find the section on Battery Chargers with the "What Size Battery Charger" sidebar.  There are two basic issues: time to charge based on house bank size and charger size where "bigger is better" to reduce time, and, in my mind more importantly, the acceptance rate of the batteries.  That means how much juice they can absorb based on their state of charge, which reduces dramatically as the amount of charge reaches 100%.  Those of us with battery monitors (Links, etc.) can attest to that.  Point being, even if you buy a 50A charger, it's not going to take much less time to fill your bank than a 40A charger, because "it takes forever" to get that last 10% into the bank.  Really.

Another great reference source is West Marine's Advisors and if you don't have the 2008 catalog, or earlier ones (which I save and cut the electrical sections out to retain), you definitely should.  I was on a friend's friend's boat who is planning to do the Pacific Cup Race to Hawaii this summer, and during our investigation of their electrical system I asked him if he had a WM catalog.  His wife said, "Oh, so many people asked us that so we went out and got one!"  I recommend you do so, and read page 390.

Finally, most all of our C34 members who are "into" electrical systems have reported great success with the Truecharge 40 both in terms of performance and capacity, with reasonably sized house banks.  As WM says, there's no sense in oversizing a charger.

Case in point is our boat.  We have 390 AH in our house bank.  Our charger on the Freedom 15 is 75A which is way overkill and well beyond the sizing suggestions, should be more like 40 to 50 max.  The reason?  It came with the 1500 watt inverter.  Now that I've had a few months to work with our Link, we do not get 75 A out of that charger, BECAUSE the batteries will simply NOT accept that amount of charge.  We see it start out at 50 and go through the three stage charging regimen, and with a 50% depleted battery bank, usually less than 50 A.

2.  Charger Selection:  As mentioned, both Jon and I have noted that the features on the XC are well beyond what you would need, but only you know what you want or need.  Based on where you sail I find it unnecessary to need to consider temperature sensors.  If I was sailing from Puget Sound to Mexico I might, just might, consider it, but then a smart charger usually has temperature compensation built in.  As I recall (but without confirming it by going on line to Xantrex) I would not be surprised if the Truecharge have cool and hot.  Sure battery temperature control is a good safety feature, I have not found it necessary.  Why?  Because I'm almost never away from the boat when the batteries are being charged.  Your boat, your choice.

So, given all that, which I'm desperately trying to keep to a minimum (those who know me say: "Yeah, right, what century???) I encourage you to apply your energies and talents from your work and home experiences to this endeavor, and work to figure out what's best for you, your companions and your boat.

Good luck should NOT enter into it, it's a PLAN that should be developed and implemented.

[Stu Jackson]

Dave,

Here's a link to a discussion about the battery rejuvenators:  http://www.sailboatowners.com/forums/pviewall.tpl?uid=73200280089&sku=2008142071303.78&forumabr=as&fno=21

[Jon Schneider]

2.  Charger Selection:  As mentioned, both Jon and I have noted that the features on the XC are well beyond what you would need, but only you know what you want or need.  Based on where you sail I find it unnecessary to need to consider temperature sensors.  If I was sailing from Puget Sound to Mexico I might, just might, consider it, but then a smart charger usually has temperature compensation built in.  As I recall (but without confirming it by going on line to Xantrex) I would not be surprised if the Truecharge have cool and hot.  Sure battery temperature control is a good safety feature, I have not found it necessary.  Why?  Because I'm almost never away from the boat when the batteries are being charged.  Your boat, your choice.

I'm not sure I'd go on record as saying the XC is "well beyond" your needs, Michael.  If you are planning on having a separate chemistry starting battery (ever) and want to charge it directly from the shorepower charger, then the XC is definitely the way to go.  The Truecharge will charge multiple battery banks at different amp levels, but they must be of the same chemistry (i.e., able to take the same voltage level).  Given how little charging a starter battery generally needs, I think some kind of combiner/echo-charger is the right way to handle charging the starting battery (i.e., charging off of the house bank rather than directly from the charger or alternator).  In that case, the ability to charge a separate chemistry battery is irrelevant.  Xantrex is pretty crafty in its charger ratings, which makes it a little difficult to compare the old Heart Truecharge (Xantrex acquired Heart a few years ago) models against its own XC series, since the TCs are in the 20 and 40 amp range and the XCs are in the 30 and 50 range.  That said, the TC 40 is $322 while the XC 50 is nearly $200 more at $515 at Defender. 

BTW, I originally bought the XC 50. I returned it and got the XC 30 when I discovered that the 50 would not charge a bank under 100AH.  Most starter batteries, while high in CCAs, are below 100AH, so I figured I'd better be safe with the XC 30, which will charge a bank as small as 60AH.  Why they engineered this product in this way, I have no idea; it seems pretty stupid to me.  Of course, now that I have configured my charging system to be entirely directed to the house bank with a feed off via the Duo Charge, the XC 50's restriction would've been a moot issue.  Since I'm only a weekend sailor (for now), the 30 is quite adequate.  In your case, with frequent usage by multiple owners, you should probably either the TC 40 or the XC 50. 

BTW, the TC does have an optional temp reader.  I would strongly urge you to get this, not only for safety's sake (although that's a good enough reason), but because the charger will limit itself to the lowest reasonable output in absence of knowing the temperature of your battery.  In effect, it will assume that your battery is colder than it might be, and thus it will slow down the charging process. 

PS: As I was just reading the June issue of Cruising World with the article about Frank Butler (great article BTW; I didn't realize he is 80), I noticed an ad for a Truecharge2 charger.  Looks just like the XC.  Comes in every amperage rating from 10 to 60, so I suspect this is a merger of the two product lines.  BTW, the XC (and probably the new TC2) has two other advantages over the original TC: 1) its price includes the temp sensor, which is probably a $40-$50 value; and 2) it has read-out display, which can be mounted remotely.  This is an optional buy on the TC.  After a quick glance at the TC2, though, I would go with this new one, if you can find it (www.xantrex.com/truecharge2). 

[jmnpe]

Hi everyone! Sorry to be so late for the party! Given the late hour, I'll probably have to do this in several sessions, but I'll try to answer all the questions eventually.

First, let me say that I am a mixed-bagger: I keep ( for the last 20-ish years) AC power on the boat 24/7 to keep the beer cold, and to keep the inside temperature of the boat reasonable with my wonderful 16,000 btu of reverse cycle air-conditioning. Down here in north central Texas, the boats never leave the water, and our temperatures can change about 100 degrees F from February to August. We don't have to worry about salt induced corrosion  up here, but I did the same thing while I had the Stamas 44 on the Texas gulf coast for 9 years by exercising reasonable preventative measures to prevent salt from causing potentially dangerous electrical hazards at the dock and on the boat. Having said that, the explanation for my veiled comment about not leaving the battery charger on 24/7 ( but not for the reason you might think ) is that I have no problem with AC power on all the time, but I have some technically sound reasons to not keep any kinds of deep cycle batteries on a charge 24/7.

All battery do not like having residual charge current flowing through their plates for extended periods of time. However, for our discussion here, I'll limit my comments in particular to deep cycle lead acid batteries. As Stu accurately quoted some of our direct correspondence, the problem created by continuous charge/residual current flow through lead acid batteries in positive grid corrosion. This is something that happens anyway during the charge process, but when the charge to float mode time ratio becomes mostly float mode, the grid corrosion continues to happen with no useful effect on the battery, so that the positive grid corrosion is highly accelerated. The grid corrosion produces increased internal impedance ( i.e. - reduced cranking capability ) and reduced deep cycle capacity from the loss of effectiveness of the positive plates. The relative reduction of capacity percentages I cited due to continuous charging versus cycle charging come from 2 primary sources: manufacturer's data, and my own empirical data from messing about with deep cycle batteries extensively since 2000. The primary manufacturer I have worked with is Concorde Battery, who manufactures not only the Lifeline AGM batteries, but also a complete line of aircraft and aerospace batteries in civil and military applications. The same family that owns Concorde Battery also owns Trojan Batteries, so the experience base there is pretty broad. Trojan was the premier manufacturer of submarine batteries during the diesel/electric submarine era. They are also still the leading manufacturer of golf cart batteries, among other batteries.

The stated 35 to 40% maximum reduction in useful life of a deep cycle lead acid battery due to continuous float charging was based upon Concorde's own testing and their experiences in field applications of their batteries in solar power applications ( the ultimate cycle charge environment ). My own customer experiences and the results of my own studies with the Lifeline batteries supports the stated range of useful life reduction with some reduced effect if the float voltage is temperature compensated and well regulated at the lower end of the allowable float voltage range. In the last several years, Concorde/Lifeline has reduced their recommended float voltage range from a nominal 13.4 volts to 13.2 volts, and this will further reduce the rate of positive grid deterioration in the float mode. In one of my own examples, the new AGM 4D batteries I installed on my Stamas 44 lived about 3.5 years in constant float mode at a temperature compensated 13.4 volt nominal. At the end of that time, the measured cranking power ( CCA ) and deep cycle capacity was reduced by about 20%. The next 1.5 years was spent using cycle charging, and the measured CCA and a-hr numbers were only about an additional 5% lower. I have to note that these examples are from premium grade AGM deep cycle batteries, and the results from a relatively inexpensive flooded battery would probably be significantly worse.

So, if 24/7 float charge is bad, what to do about 12 volt refrigeration ( i.e. - your Cold Machine )? The simple answer is to provide a suitable AC-to-DC power supply to run the fridge when you are at the dock, and then run it on the batteries when away from AC power. I have been doing this since 2002. There are a number of inexpensive and suitably reliable small switching power supplies out there that will do the task admirably.

One last quick comment: I like the TrueCharge + series because it has been an extremely reliable product with good features and performance at a fair price. I have never seen one fail at all in normal service in 8 years, and more importantly, never fail in a mode that produces an uncontrolled high output voltage across the batteries. This is in stark contrast to may of the other charges that were in use on boats over the same period of time. I think the TrueCharge II has excellent potential, but I want to see some in operation over time before I offer any additional opinion. I think the XC series is over-priced and touts primary features that offer little benefit in the real world.

This will have to be it for installment #1. I'll keep working down the list of questions and comments as quickly as I can.

John

[Michael]

Stu and Jon [and John, who has come to the party since I first posted the following], thank you for your detailed postings on this topic.  I hope many other readers are making decisions about battery chargers and can benefit also from your messages.  In hopes of buying some time to make a decision on a new charger and battery monitoring system, we plan to test (as suggested in a recent posting on the carbon monoxide thread) to see whether the old Flyback 20-3 can safely be used pro tem.  Work has started on an energy budget, following your precedent, Stu.  Nigel Calder's book, the WM catalogue, and your other suggestions for reading are next.  So any decision on the new equipment is a ways off.  Jon, thanks for the information about the new TrueCharger2s.  I hadn't heard of them.

[Ken Krawford]

John,

Thanks for your insightful input on batteries and charging.
I am one of those who leaves refrigeration on all the time and have struggled with the problem of constant battery drain/recharge.  I considered a switching power supply and called Adler Barbour to get their input.  This was about 2-3 years ago so I don't remember the details of the conversation but the final analysis was that this is not a good idea.  I hate people who ask for advice and if it is not what they wanted to hear, they ignore it...... however your post (and credentials) compels me to revisit this issue.
Can you give us a few details on the specs of the power supply you are using and how it is wired into the system?
Thanks.

[Jon Schneider]

John, I love your idea about direct AC to DC conversion for the fridge.  I actually wanted to do that several years ago, but the distributor (Waeco) told me not to do that.  I can't remember the reason (or even if they had a good, intelligible one), but the fact that you've done it and it has worked is fantastic news.  I second Michael's request for any specifics you might have about the power delivery design.

Regarding the float charge controversy, I agree that a continuous charge would have a deleterious effect on the battery's grid, but Xantrex told me -and I have since confirmed- that the float stage does not equate to always on.  It's actually a cycle stage that if the charger senses no difference in voltage level in the battery, will only cycle on every 21 days (this was in regard to the XC 3012).  If this is true -and I normally will see the charger register 0 amps when I return to the boat after a week- then leaving the charger on should not have the impact you have described.  That said, if you leave the fridge on, the charger will come on frequently if not continuously, so your direct AC solution is a great one.

[Stu Jackson]

EARLIER FRIDGE WIRING CONNECTION BATTERY ARRANGEMENTS

Ray Irvine had wored out a nifty solution many years ago.  See Reply #16 here: http://c34.org/bbs/index.php/topic,2143.15.html

The CO discussion Michael refers to is here: http://c34.org/bbs/index.php/topic,4313.30.html (It's a long one, too.)