What causes your Battery to boil?

Where’s Mex??… Kinda miss him, I hope he’s ok…:R

3 tons

schlep1967 wrote:
After getting the battery tested and being told it was good we got distilled water and topped it off. At this point we were thinking bad WFCO converter. We bought a multi-meter and checked the voltage when we hooked it back up. It was never higher than 12.7 volts but the battery got hot and started boiling again after an hour.
The voltage was not high so I was thinking a shorted battery.
We replaced the battery. It was hooked up all night with no increase in temps or boiling.
He doesn't keep his trailer plugged in all the time. Hopefully everything will be good when we are ready to go again.

at 12.7V that charger isnt even on. hooked up you should be getting much higher than that if the battery is good. I would try swapping out a different battery for a few minuits and do the voltage reading again. if it is up in the 13s then you know your battery has a dead cell and you can tell autozone there full of $%#@&. if it is still 12V then somthing else is going on thats going to be a bit more work.

Steve

time2roll wrote:
If 12.7 is boiling the battery there is a shorted cell. The shorted cell makes it a 10 volt battery. 12.7 volts is too high for a 10 volt battery.

Doubt the test was accurate. Did the battery actually pull the rated CCA for 30 seconds and remain above 8.4 volts? Or was this some digital magic box?

I have no idea what type of test Autozone does.

I mostly posted this to let others know about the issue.
My first search about RV's and boiling battery on Google resulted in answers definitely pointing to the converter as the most likely culprit. As can be seen here that is not always the case.

After Autozone (being told the battery was good) we went to the local RV place (Camping World) and got the price and model number. Then went online and found the same item for $125 less. Since they were not buying from CW we grabbed a cheap multimeter from Wally world on the way back to the campground to check the voltages.

So Autozone told us we had a good battery, we didn't. And camping world would have been happy to sell us a greatly overpriced converter. No sale. And a $16 multimeter actually told us where the problem was.

That cheap multimeter is staying in the camper.

schlep1967 wrote:
We were camping with some friends this weekend. He thought he had a sewer issue until he figured out it was his battery outgassing. The thing was boiling.

What would cause this? We took the battery to Autozone and it tested as fine.

There are several causes of battery boil
OVERCHARGE is #1 on the hit parade.. Some older converters like the Magnetek 6300 series do not know when to slow down and switch to FLOAT. they just keep pumping out amps (And not that very many of 'em) so if you are plugged in long enough.. they boil your batteries.. Others can do that if the adjustmet is off (Assuming there is an adjustment) or the voltage regulator fails.

Charging too fast.. For example charging a Group 24 battery with a 60 amp charger... (The proper rate is closer to 25 amps)

And finally a shorted cell. turning your 12 volt battery into a 10 volt (or less) the rest of 'em now get over charged.

These are the big 3.. there are more.

Dendrites may have grown and caused a short. The battery "passed" the load test because the high amperage draw may have temporarily burned off the tip of the dendrite.

“We took the battery to Autozone and it tested as fine”

A fine battery will boil with a bad charger. After only a short time the battery won’t be fine any longer.

If 12.7 is boiling the battery there is a shorted cell. The shorted cell makes it a 10 volt battery. 12.7 volts is too high for a 10 volt battery.

Doubt the test was accurate. Did the battery actually pull the rated CCA for 30 seconds and remain above 8.4 volts? Or was this some digital magic box?

schlep1967 wrote:
After getting the battery tested and being told it was good we got distilled water and topped it off. At this point we were thinking bad WFCO converter. We bought a multi-meter and checked the voltage when we hooked it back up. It was never higher than 12.7 volts but the battery got hot and started boiling again after an hour.
The voltage was not high so I was thinking a shorted battery.
We replaced the battery. It was hooked up all night with no increase in temps or boiling.
He doesn't keep his trailer plugged in all the time. Hopefully everything will be good when we are ready to go again.

Likely one dead cell, which results in overcharge of the other cells.

BTW WFCO is known for almost never ever going into bulk charging mode, usually stays at 13.6 or so max

After getting the battery tested and being told it was good we got distilled water and topped it off. At this point we were thinking bad WFCO converter. We bought a multi-meter and checked the voltage when we hooked it back up. It was never higher than 12.7 volts but the battery got hot and started boiling again after an hour.
The voltage was not high so I was thinking a shorted battery.
We replaced the battery. It was hooked up all night with no increase in temps or boiling.
He doesn't keep his trailer plugged in all the time. Hopefully everything will be good when we are ready to go again.

Avoid boiling by using a quality recharger.