Hot Battery

[Vincentc]

The port battery bank was too weak to start the generator this morning. I checked the port side forward battery (Lilly Marie has 4 8 d's, one pair for the port engine and generator and the other pair for the stb engine and house) and the water level was well below the plates in all cells and the plates looked as if they were broken at the top. The aft port side battery had the same low water level plus the labels on the battery looked as if they had been heated. They were brown around the edges.

I've pulled both port side batteries and am replacing them, but wonder if I have some other problem which caused the water to boil out. It has been a while since I checked the water level, but in the past the batteries were not using significant water.

Any thoughts on the cause and what should be done to check this out?

Thanks in advance for your suggestions.

Vincent
Lilly Marie
43 DC 1983

 

[SKYCHENEY]

One bad cell will cause the charger to see a low voltage and to overcharge the entire bank. This will boil water out of all but one cell (the bad One).

 

[Vincentc]

Thanks Sky,
I didn't know that, and it fits with my experience. The last time I checked the batteries with a hydrometer, it appeared that there was marginal cell(s) in one of the port batteries.

The Stbd bank water level is fine.

I replaced the 8d with a 31 which is rated to have enough CCA's. It cranked a cold 671 just fine, though cold today is 65 degrees.

The forward deck coring is repaired and the pulpit is back in place. Once I get the windlass installed, it is probably time to get started on the bank for the inverter.

Vincent

 

[spartonboat1]

One bad cell will cause the charger to see a low voltage and to overcharge the entire bank. This will boil water out of all but one cell (the bad One).

true, true, have had that exact experience. Batt will get very hot. Replace, asap (lead acid that is). Don't know about the gel's.

 

[Walter P]

I had the same experience a few months ago. It appears to be more common than I expected. Is there anything that we could have done or not done to prevent this problem? I replaced 2 8D's on my port side and since the cable connections looked nasty, we replaced the battery cables which by the way cost more than the new batteries.

Walt

 

[REBrueckner]

It would be interesting if you guys posted the brand name of your batteries.
I've used POWERMASTER over the last 11 years and a dead cell caused the batteries to weaken, but not overheat.

In any case there is not much you can do about it once a wet cell battery ages. You can length battery cell life by not discharging too deeply, normally not over 50%,by recharging promptly to avoid sulphation crystallizing and by checking your battery charger voltages (and charge settings: wet cell, AGM or gel).

I would think AGM batteries would NOT suffer this problem but not having used them cannot verify that.

 

[Maynard Rupp]

When I bought my last 8D, I was told that all lead acid 8Ds are made by one manufacturer. We have two in our Hat. One is an Interstate and the other is a Decca. If they really are "all made by the same manufacturer", we should shop by price only.

 

[Pascal]

One bad cell will cause the charger to see a low voltage and to overcharge the entire bank. This will boil water out of all but one cell (the bad One).

one compelling argument not to but all your eggs in teh same backet... or all your batteries in the same bank!

one tell tale sign of impeding failure is a rotten egg smell. a heat sensor on each battery woudl be a great safety feature to prevent such problem and possible a battery explosion...

 

[MikeP]

Of course, Pascal is right - one large batt bank, though more efficient, is subject to the whole setup going bad due to one bad cell. I had the same thing happen in one bank (4 batts)- one bad cell and the other 3 batts were cooked. But the batts were 6 or 7 year old Dekkas charged by the oem Ferro charger so I wasn't too upset.

I must admit however that despite the above, I put in all new (8) batts in and wired them all into one large combined bank charged by the smart charger on the Outback 3232. Battery switches allow everything to be returned to the oem setup, including use of the LaMarche charger. No actual OEM wiring was changed.

 

[fissioneng]

a heat sensor on each battery woudl be a great safety feature to prevent such problem and possible a battery explosion...

The Xantrex chargers have a battery temperature sensor that will warn first and then shut down the charger if it senses high battery temperature. Before I installed this charger, my Sentry cooked 2 8Ds because one had a bad cell.

 

[SKYCHENEY]

One good way to catch a cell going bad is to use your hydrometer every so often and check the specific gravity of each cell. If you've got one that is significantly lower than the rest, it's probably time to get a new battery. I know, I don't do that either. There seems to be more important jobs than that, but it would let you know what's going on.

 

[Timeout]

I was so frustrated with the batteries beating each other up on my 43 that I reduced each side to 1 8D instead of 2. This is plenty of power for a 43DC with port side for port engine and generator and stb. side for stb. engine and house (not much house 12V power needed on 43DC). Still have crossover if needed. No problems since making this change and batteries seem much happier (no need to add water in 2 years). Also less costly and less weight to carry around.

 

[spartonboat1]

It would be interesting if you guys posted the brand name of your batteries.
I've used POWERMASTER over the last 11 years and a dead cell caused the batteries to weaken, but not overheat.

In any case there is not much you can do about it once a wet cell battery ages. You can length battery cell life by not discharging too deeply, normally not over 50%,by recharging promptly to avoid sulphation crystallizing and by checking your battery charger voltages (and charge settings: wet cell, AGM or gel).

I would think AGM batteries would NOT suffer this problem but not having used them cannot verify that.

Lead acid batt life can be lengthened by running special cycle called "equalizing" that combo inverter/chargers have in their software. When activated, it overcharges the batteries at a controlled rate, for a period of 8 hours or so, high at the beginning and falling off by the end of the period. The effect is to stir up the lead from the bottom of the batts and re-distribute it on the plates. This process effectively prevents the plates from shorting out to the bottom across the lead that has fallen to the bottom of the cells, plus the lead that had fallen away is re-used.

Problem is you have to remember to do it once or twice a season and probably best to do it with the hatches open or cracked to let the gases out.

I have a Heart (now Xantrax) 2000 unit that has this feature.