Batteries No Holding a Charge

[alanperry]

The two 8D 240 AH batteries that I inherited with my boat do not seem to be holding a charge. (Flooded) I have all new wiring, all larger than required by several factors, new alternator, new Balmar regulator and Blue sea Battery ACR which isolates the start battery from the house bank during charging and discharging. I have a small marine start battery used only for starting.

At the dock the batteries are charged by a newmar basttery charger.

During my most recent outing using interior light sparingly, and my anchor light from dark until first light, my Voltmeter on my Blue Sea Panel would show only a little over 10 Volts by morning. I have few electrical devices except for radios, navigation etc. but these are off most of the time and virtually all the time at anchor. There is no refrigeration, air con etc.

Now since there was no wind I motored most of the first day getting thru the locks and from Seattle to Port Townsend. About 6 hours. My Balmar regulator was indicating that it was charging in accordance with it's "smart" profile. At this point the Voltmeter shows 14.6 Volts. But overnight the batteries seem to lose their charge and I wake up to the meter reading 10+ Volts.

If I test them with a Hydrometer will that test actually show true battery condition?

I suspect that the previous owner, who used the boat as a live-a-board probably overcharged them at the dock or run them down. The Batteries are probably two and a half years old.

Any ideas or advice?

[By Invitation]

First thing I would do is to measure the voltage on your battery posts during your charging cycle to see if you really have the 14+ volts at the posts. If you do, you have a battery problem, if you don't you have a wiring problem.

By the way - from your post it looks like you have a CL41 - so do I !

[alanperry]

BI, yep a 79 CL 41 the CL design not the Ray Richards. It's a great boat.

I have done that and it measures over 14.

[By Invitation]

Time for new batteries. Sorry.

[hellosailor]

Alan-
Forgive me if this is obvious...but have you checked the fluid level in the battery cells? There's usually a level mark of some kind but the general rule of thumb is to have fluid just above the level of the plates. If the batteries have been overcharged and dried out, you MIGHT be lucky and just need to add distilled (or de-ionized, way cheaper) water.

A hydrometer tells you the same news as a voltmeter, more or less, but it also can tell you the condition of EACH cell, making it easier to locate a bad cell. (Not that you can swap one of them out, it's just a way to make the diagnosis.) If you buy a hydrometer, buy the 10-12" long kind (easier to read) with a hard case to protect it. That also helps prevent the acid on it from spreading around--cheaper in the long run!<G>

If the PO let them overcharge, dry out, or sulphate (like by leaving them alone for 4-5 months each winter) or simply deep cycled the 100% a couple of dozen times, yes, they really could be killed by now.

[btrayfors]

Alan,

Not necessarily time for new batteries. Here are a couple of things to check.

1. By all means measure and record the specific gravity in each cell. You may find one that's bad.

2. Assuming that the batteries are really only a couple of years old, and that they were not run dry (with electrolyte level below the top of the plates), and that you don't have a bad cell, it's most likely that they are sulphated due to improper charging. A battery starts sulphating at the factory, from the moment the sulfuric acid is added. Proper charging to 100% capacity and occasional "equalization" with voltage above about 2.6VDC per cell is needed to keep the plates free of lead sulphate crystals, so that they can accept and deliver their full energy as designed. Letting batteries sit for extended periods at less than full charge will cause them to sulphate badly over time.

What to do? You have a couple of choices.

1. Give the batteries a full charge, then try equalizing them. Then, cycle them a few times (full charge, deep discharge, full charge) and see if they recover.

2. There are a number of desulphation devices on the market, with more appearing all the time. I'm in the process right now of testing some of these on a variety of batteries. It will be a couple of months before we'll be able say anything with confidence about whether or not these devices do anything good, but there's a growing body of anecdotal and semi-scientific evidence to suggest that they well might. Since they're pretty cheap, I think in your situation I'd give one a try and see if it doesn't help over the next few months. If not, well, you can always use it on the new batteries where it will likely help extend their lives.

Anecdotal, preliminary evidence from the tests: at the start of our testing we had two "bad" batteries, one golf-cart sized gell 10 years old and one T-105 Trojan flooded battery 4 years old which had been badly mistreated. Both failed the internal resistance checks, and their calculated CA was very low. Both of these "bad" batteries, in two separate banks, seem to be doing considerably better after several cycles of charging-discharging-charging followed by just two cycles of charging/pulsing-discharging-charging/pulsing. THIS IS ONLY INDICATIVE, NOT DEFINITIVE, in the absence of further testing and analysis of the data.

BTW, I've got two old and very mistreated 8-D AGM batteries on charge right now to add to our testing. They came to me in a sorry state, with voltages under 2VDC! One had even been dropped several feet onto it's corner, as the lifting strap broke. We'll see what happens when the pulsator is attached!

Good luck,

Bill
S/V Born Free

[Duckhead]

I just bought a charger at Sams club. It has a 24 hour long recondition/desulphation cycle that I just used on the runabout batteries... whoa ! it works! Batteries wouldn't take but 13 V ...after desulphate, more like 14V. The thing cost less than 30 bucks. Duckhead

[Vasco]

Duckhead,

Most of the new "smart" chargers have an equalization cycle. In fact I have a ten year old charger that has an equalization cycle.

[Jentine]

Alan,
I just had the same problem with my batteries. I had one 4D and two Trojan 105's. The specific gravity of each battery was in the range of 1.125 to 1.135. That is a far cry from the ideal of 1.300. I charged the batteries and put them on a series of equalizing charges until the specific gravity rose. I could not get the specific gravity of the 4D above 1.235 which was not acceptable. The T-105's reached 1.265 so I changed the 4D and replaced it with two more T-105's. The problem is gone. I have more power than I can use.
Reference: http://www.nwes.com/using_batteries.htm

[exranger]

Does this mean these devices may save 4 batteries I have that were in the boat when i bought it, but completely drained and not having a charge?

[Duckhead]

Up till now haven't bought a battery charger since the 70's ...glad they have done something with them to make them better. When I was a tech in military we had a hell of a time keeping big batteries in trucks in warm weather (Egypt). The fix was quite simple ...specific gravity was reduced to 1.2 on new batteries. This obviously reduced cranking power by a small margin but increased life two or three fold. Just a thought. Duckhead

PS if you are in the market for new batts, at least consider 6V golf cart batteries (again at Sams'). They are made to be rugged for obvious reasons and they are a bargain for the size.

[hellosailor]

exranger-
They are meant to undo a limited amount of sulphating, not resurrect the dead. If your batteries were left dead for a long time, the odds are they need replacing. And one of these low-amp chargers would have a problem dealing with four batteries of any large size. You might have to leave on of these on each of your batteries for a month in order to see what effect it might have--but the odds are, new batteries.