exploded battery

You need to get a garden sprayer.. Fill it with water and baking soda, as much soda as you can disslove in the water, and hose down EVERYTHING near that blown up battery,,, You may see many areas "Fizz".. this is good as the soda is kicking the acids ... ER.. acid. Once it stops fizzing hose it down with the garden hose.. Do not worry about getting wires wet so long as they are 12 volt.. Once you have washed and rinsed.

Replace BOTH batteries

And check your reverse polarity fuses or breakers.

The most common reason that a battery explodes when NOT being worked on in some way is an internal short. Builds up heat and off gasses sulfuric acid and hydrogen fumes until it just blows up. Often you will see the sides bulging and it will ALWAYS put out a stinky odor when this is occurring. If you see any battery exhibiting these characteristics disconnect the power immediately. That's a good reason wearing safety goggles is a really good idea when working around batteries.

I think that it was being charged, which causes hydrogen bubbles. But something failed inside the battery, like a cell connector. Since it was being charged, there was a spark and it detonated the hydrogen/air mix above the electrolyte. In any event you should sanitize the area with baking soda and water. You may find some of the paint comes off. And, agree with the others, good thing you are replacing both batteries.

It's possible, of course, that the spark came from the outside of the battery too. Like a short got across it or to ground. Or a connection right by the battery went bad.

I blew a battery up testing a starter once. Made a BANG, lifted the top, split the sides, and let the electrolyte out.

I will caution you against hooking up the old battery in line with the new ones. From what I understand, the old battery will drag the new batteries down and kill them dead in a short period of time. I know that the thinking is that the new batteries will "support" the old one - unfortunately, the opposite is true.

Cheers!

Mike

I suspect your 2001 model single mode on-board converter/charger unit has boiled out your battery fluids over time and then the winter froze up the battery.

The older converter/chargers only put out 13.6VDC and this is just right on the edge of boiling out your battery fluids over time. I lost one the same way. I had to start inspecting the battery fluids at least every two weeks to make sure they was not boiling out fluids..

I eventually replaced my older converter/charger with a smart mode version. I went with the PD9200 series units.

Just a couple of my theories...
Roy Ken

What's the point of leaving it plugged in all the time if you aren't using it to warrant the need to keep it plugged in all the time?? Is it just to keep the batteries charged??

I keep my trailer parked and covered all winter too, but I only plug it in when needed... Even covered, I've used it for an extra room for house guests.. I pull the battery from it and keep it in the garage. Plug it in when needed.

My converter allows for it to be plugged in without a battery, so you'd have to check to make sure yours can do that too..

Anyway, whatever works for you is the way you should do things, but for the last 12 years, I've been disconnecting the battery and I actually still have the original DELCO battery that came with the trailer, but I do use a newer TROJAN for it now, but it's getting to be about 6-7 years old now too....

Oh well, get some new batteries and try a disconnect switch and a trickle charger on them and leave the rest of the rig unplugged.. Or continue with what works for you and be happy! :)

Mitch

A fully charged battery does not freeze, maybe it was low?

If the batteries were both 5 years old I would probably just go ahead and retire the one that didn't blow up. I've never been a big fan of mixing batteries in a bank.

Sorry to hear that.