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Chuck&Pam · 03-31-2015, 05:07 PM

Spring has sprung and I need a new chassis battery. It would not hold a charge on converter/charger or alternator. After charging, it pretty quickly showed voltage drop to 11.3v. (Alternator is ok...while engine running battery terminals show voltage of 14.4v.) Measuring the SG of the electrolyte in cell #5 wouldn't even float the bulb. It was about 7 years old.

I had the coach connected to shore power all winter. Sometime, one of the house batteries blew some electrolyte out the valve cap. In fact blew off its cap. No swelling or bulging or anything like that is apparent. The house batteries take a full charge and all the electrolyte measures show good, and all are the same value. My battery configuration is 2 6v deep cycle batteries on charger/converter.. no inverter.

So here's the question; would the charger keep the batteries on bulk charge thinking they were low due to the chassis battery not holding charge? Thereby over charging them causing the gassing?

My take is that I'm OK with the house batteries (only 4 years old.) What say ye?

Ray,IN · 03-31-2015, 05:41 PM

The charger was over-charging the batteries, causing the cap to blow off and spew electrolyte everywhere. That battery must be replaced, which brings up another issue. If the batteries are not all the same type, age, and conditon, you may be just spinning your wheels and throwing money away buying one battery. The only way to know is to have all of that battery bank tested by Interstate or other such battery company.
The next step is to determine the condition of the charger output =cause of the battery exploding.

t55watson · 03-31-2015, 05:48 PM

I often wonder why take a chance of over charging with it plugged in all winter? I leave cars,trucks and boats all winter with no plug ins and they winter fine. I do give them a full charge before I leave home for sunny climes. The DP sits all summer without being plugged in, isolaters off, and they to work great. Just saying.

wa8yxm · 04-01-2015, 08:06 AM

What converter do you have on that puppy?

Chuck&Pam · 04-01-2015, 10:02 AM

hey YXM...it is a WFCO WF-8865. 65 amp charger/converter. I've not checked the output yet on it but will when I reconnect all the batteries. It's a bear to check since it's underneath the refer and has flex duct work running all around it. However I don't suspect anything wrong there.

superk · 04-01-2015, 06:30 PM

I agree with the previous posters. Its probable that the charger over-charged them.

You would benefit more from a battery maintainer (1.5amp trickle charge), as they will discontinue charging when the batteries dont need it.

Any battery that has suffered physical damage (yes, its damage) should be replaced. If its part of a bank, unfortunately, the entire bank should be replaced with identical batteries.

The coach batteries typically are isolated from the chassis battery. whether its a switchable isolator or not depends on your coach. I think most are.

Chuck&Pam · 04-15-2015, 11:23 AM

Update..the charger/converter is fine. I'm replacing the house batteries to be on the safe side. I believe my poor maintenance schedule has contributed to their premature demise. (they are 5 years old)

I'll do better from now on, and thanks for all the replies and help. This forum is always great!

PS. .the trees are fully green and the humming birds are back this week so spring has finally arrived here in central Carolinas.