Interstate battery out-gassing and bubbling out water while on shore power

[Consultlkr]

Anyone have a problem with out gassing and loosing water from your interstate battery while connected to shore power? Our 2018 Serenity has gone through about 1 gal of distilled water in 2 weeks. You can hear it off-gassing, and see water/acid running off the top of the battery and dripping on the ground. Our Airstream dealer replaced the batteries about a year ago because they were dead, and told us to keep water in them. (Duh) Is this normal to go through that much water in such a short time- even on shore power? Could this be a problem with the charging system or something else?

Thoughts appreciated.

[dznf0g]

Not normal!! It sounds like your converter is putting out an extremely high voltage. Measure the output voltage and post results.

[Consultlkr]

Originally Posted by dznf0g

Not normal!! It sounds like your converter is putting out an extremely high voltage. Measure the output voltage and post results.

Thanks for the quick response. I have a meter but where do I measure the voltage? On the battery posts?

[reginac]

Originally Posted by Consultlkr

Anyone have a problem with out gassing and loosing water from your interstate battery while connected to shore power? Our 2018 Serenity has gone through about 1 gal of distilled water in 2 weeks. You can hear it off-gassing, and see water/acid running off the top of the battery and dripping on the ground. Our Airstream dealer replaced the batteries about a year ago because they were dead, and told us to keep water in them. (Duh) Is this normal to go through that much water in such a short time- even on shore power? Could this be a problem with the charging system or something else?

Thoughts appreciated.

I had the same problem in my flying cloud but I have AGM batteries. Do you have solar? Apparently this is a super common problem. Having solar and being plugged in can mess up the converter and make it overcharge the batteries. I replaced/upgraded the converter and it instantly fixed the problem. It was a cheap fix too. Email the airstream tech help line and they can guide you. I found it in the airstream magazine. If you can’t find it let me know and I will send you a pic.

[dznf0g]

Yes, with converter on measure across the battery. Do it again when solar is charging as well.

[ROBERT CROSS]

Maybe...test twice, before it's plugged in and while.
The batteries could be damaged again. 🥴
Bob
🇺🇸

[dznf0g]

Also, I wouldn't waste any time, after your test, to properly clean up the acid spilled. Remove batter(ies), and flush the box thoroughly with water. Then sprinkle, liberally, baking soda over the area where the acid has touched any AS parts. Work the soda with a sacrificial brush. Repeat.
The acid will reek havoc on all the metal parts.

[jaybauman]

I assume you have 2 12volt batteries wired in parallel. Is your problem happening with both batteries or only one? While a converter malfunction could be causing these symptoms, there may be a different root cause.

When batteries in parallel have different impedances (e.g. old/new batteries together, 1 battery with a dropped cell, 1 battery with low electrolyte, 1 battery with shorted electrodes, etc), one will "drive" the other, up to the point of the stronger battery running the weaker battery into reversal. Then the converter sits on top of all this trying to drive an electrical current into the process, which exacerbates this runaway loop. These overcurrent conditions would split a lot of water, resulting in hydrogen venting and subsequent water loss.

It's a lot cheaper and easier to do a pro-rated warranty battery replacement than to swap converters. To help diagnose, take both batteries into a shop that can run a load test, which will indicate if both batteries are in similar health to each other.

Incidentally, this is one of the main reasons that it's a good idea to replace all batteries in a parallel arrangement at the same time, rather than "just the bad one"...

[n2916s]

If you measure it and get a voltage above about 14, shut it down as in flip the breaker for the converter. Whatever voltage is across those posts is also being supplied to the control boards of your reefer, water heater, furnace...

Let us know what you find.

[uncle_bob]

Hi

Lots of possibilities:

1) It's really hot out. The converter charger is not temperature compensated. It will push out a bit of water if the temperatures are quite warm ( like over 100 F).

2) You have lost a cell in one or both batteries. You should notice this on your voltage readout on the trailer. It should be yacking about low battery ....

3) The converter / charger has issues. Measure the converter / charger at the output posts on the device (when on shore power). It should not be over 14V. If it is .... time for a replacement.

4) Solar could be doing this, but that's rare. It really doesn't put out enough power to nuke batteries. Same thing as with the converter charger, measure it at the output leads of the solar converter.

There are a few other really odd possibilities, I'd run through the list above before getting into them.

Bob

[Buckless]

If all cells are boiling, most likely batteries are being over charged and will ruin them.
You may disconnect one battery lead to save batteries or unhook shore power.