I've never had a battery issue. No blown fuses or anything like that. Car always starts. I went to the store and I got back in the car and turned the key. I hear a Bang. I turned the key again and the dash dimmed.

I opened the hood and the battery blew out all the panels. I removed the battery to avoid more acid spilling in the battery cavity. I went and bought another battery and disposed of the old battery. The car started up and ran fine. No fuses blown or anything.

My question is: What would cause it to blow up? Defective battery? Its about 4 years old. I have checked the amps yet I'll check that when I get home.

Another possibility is a faulty alternator! Mine was in bad shape it was putting out 19V!!! My battery had started leaking - and for all I know it may have exploded. I was also getting ABS/TRACS codes (no voltage / low voltage to ABS unit???). I replaced alternator + battery and all is fine now. I am glad I found the problem in time.

If that acid isn't cleaned up ASAP, you are in for some massive rust issues in the area that the acid got around. Get a big box of baking soda, and a bucket full of water... mix and just dump under the hood by the battery. Then start taking things apart to get to the acid exposed areas. The faster cleaned up the better

i poured a couple buckets of water in the area shortly after. That evening I poured some baking soda in the area to neutralize any acid that might still be there.. I left the Baking soda to this day. I check the cruise and it works (even though I never use it) I think the acid poured straight to the ground and some on the plastic bat tray.

this happened to a freind of mine , scared the daylights out of him,
you need to maintain your batteries volvo owners.

they have water in them that needs to be maintained

it wasnt a volvo battery. it was a motomaster battery. maintenance free battery.

I friend of mine owned a small town Sears mail order store that
sold a lot of car batteries. Over the years he said he had one
customer battery explode. So, it does happen.

Good example of why you should wear safety glasses when working
around a battery or jump-starting a car.

Just a guess but if there was a lot of build up on the plates (sulfation?) and a cell shorted under starting load there may have been an arc drawn which ignited the hydrogen / air gas mixture inside the battery. Sounds like a mess. Pull everything out from around the battery tray (and the tray) then use baking soda & water to clean out the spilled acid. The Cruise Control servo is under the tray so be sure to clean it also.

Was the water low?

Again, just a guess.
--
Erwin in Memphis, '88 745t 193,000 miles, '95 855t 96,000 miles

Hi Erwin, no the electrolite was good at the time. Not anymore though.
It was very acidic and the spillage sizzling on the road.
I suspected the cells shorted causing it to explode. There was still power to the car (ie lights) Probably around 8v since 2 cells were gone (at least)
I'm at work right now and cant do the clean up.
I've just never seen a battery do this before. Big gaping holes and blown panels.

scary! Maybe the Optima gel battery isnt such a bad idea!