Haven't driven in the teener in a few weeks and today was an off Friday so good a time as any. Had the battery on a tender so figured I'd be good to go. Battery is aprox. 6 month old conventional wet cell. I unplugged the tender then unclipped the battery clips. Did a quick feel of the battery to make sure it wasn't hot all felt/looked fine. Got in the car, turned the ignition key on and BOOM !!!!! I turned the key off and my mind was racing was that an engine boom or ??? Popped the hood and first thing I noticed was one bank of three battery caps were gone. Looked around a little bit and found it laying on the engine shelf. The cap was OK not cracked or mangled. I wasn't going to risk anything so pulled the battery. Under closer examination the battery case was cracked by the negative terminal. Took the battery to where I purchased it and there was no argument they gave me another new battery. Same type same brand. Put the new battery in the car and she turned over/fired right up like nothing had happened. So defective battery or charging issue or ????

Charging? Hydrogen gas build up...add spark.

I bet it hosed the engine bay with battery acid.

get out the baking soda

Ran my hand over several spots in the engine bay I don't see or feel any battery acid. I even ran my hand under the engine lid nothing. It's as if it was just enough to pop the caps and crack the case but that's it. Not even a spec of acid on the air cleaner assembly. I have a battery mat it is bone dry. I think I got lucky.

If there was even the slightest amount of acid, it could be weeks before you notice anything. Mix a batch of baking soda and water and spray it around. If it reacts anywhere there might be a bit of acid that needs washed off. If it doesn't, then there isn't any acid and all is good. That's worth about 2 cents I'd say.

I'll do the baking soda wash tomorrow to be safe.

where did you find a battery that still had caps?

To my knowledge every wet cell battery that is not AGM has caps. Not individual but two caps covering 3 cells.

not here in ny, even motorycycle batteries that are fill and charge don't have caps anymore. fill with acid, press in barbed cover and charge. no reopening again. all the car batteries I have bought from interstate battery distributor for the last ten years are sealed wet cell plug and play. haven't seen caps on a battery in at least that time.

Always wash/rinse, that off *IMMEDIATELY*(don't be slow)
bad (battery acid)seriously

All cleaned up no big deal I used a gallon of baking soda solution I really saw zero evidence of any battery acid but used it all and rinsed real good.