Went out to the garage to warm up my vette this morning to go for my weekly "exercise the ponies" ride, disconnected the electrical cord to my battery tender from the receptacle, climed in, hit the ignition switch and explosion right behind my head! Rung my bell! Acid went everywhere. The vapor almost looked like smoke. Spent the rest of the morning cleaning up the mess. Almost the entire top of the battery was gone. Highly concerned I'm going going to have to file an insurance claim as there's no telling how far that vapor went. Will show it's ugly head in time with rusty spots on anything metal, not to mention cloth top, carpet and upholstery, I presume. Anyone else had this or similar experience or any advice?

I would seriously like to learn anything I need to from this. I've owned multiple Corvettes and always kept trickle chargers on them due to not driving them on a daily basis. Could I have caused this? Did my battery short internally? Did my charger over charge?

Bad connection somewhere! Sounds like you leave the tender hooked up and just plug it in. With the leads hooked to the battery and you move them in the process of driving, you create sparks. Battery vapor is HIGHLY explosive, but you know that, and any time you have a short or spark you have possibility of ignition of vapor. Rule of electronics: Ground=Off first on last.

I suspected a spark ignited the gases and I looked to see if the cables were loose but none were. My charger has eyelets on the battery connector and mount to the side post battery cable bolts. Battery was still locked down with the clamp at base. Still could have arced somewhere but doubt it came from the charger connection.

Baking soda mixed with water to help get any acid nuetralized,as quickly as possible. As mentioned the battery while charging does give off a gas, mainly hydrogen gas. Dirty posts tend to be the culprit for a spark, however as for the gas emitted from the battery,that is probably caused by either a low water situation in the battery itself or from a bad/shorted cell. When a cell is shorted, it's just as it sounds,two plates in that cell touch,creation a short in the cell. This short creates a lot of heat when charging basically boiling the electrolyte in the battery. Actually it's more like electrolysis, separating the components of the acid into hydrogen gas and sulpher deposits. These sulphur deposits are usually the root cause of a short,they can bridge across the plates completing a circuit. Batteries left discharged are more prone to this happening. Anyhow, hopefully the cover was down over the battery to minimize the spray,but chances are whatever carpet it got on will show holes or deteriation in short time. Plastic usually is not affected by acid, but leather is. Still, I would soak what I could with a mix of baking soda and water(or get an aerosol can of battery cleaner, it's usually the same thing just easier to spray in spots).

|UPDATED|8/31/2016 10:39:04 PM (AZT)|/UPDATED|

Thanks for your post. The terminals were clean when I removed the battery. I suspect an internal short. Unfortunately, I suppose, the lid was open and there was a large amount of vapor inside the car. Made me wonder what would happen if the door had been latched? The explosion seemed loud enough that makes me wonder if it would have blown out the fiberglass compartment? Guess I'll talk to my insurance company today as I suspect I'll be replacing a lot before this is over with.

I suppose I'll go ahead and replace the battery today so I can get it out of the garage. Anyone want to recommend a safer battery?

As for a "safer" battery, well probably an Optima, or some other AGM type battery as they are sealed, and the electrolyte within them is a paste instead of a liquid making it less likely to produce sufficient amounts of hydrogen and oxygen gasses making an explosion less likely.... however, they do come with a premium price...  but I've never seen one that blew up(18 years with a battery distributor but they are a bit more sensitive to being overcharged...... and yes, when a battery does blow up, its LOUD!   like 12 gauge shotgun loud, at least it can be, sometime they just "pop" like a paper bag.  Usually the force from the blast is focused upward, not so much outward, so, the compartment might have survived the blast.  

I always keep mind on a tender but my T tops are always off also in my garage.  Switched to an  Optima on my last battery buy.  I like the Optima so far, had it over a year now, maybe longer.  Red top Optima.

Unfortunately, Otima batteries are now not that good.  Ever since Johnson Controls bought them a few years ago and moved manufacturing to their Mexico plant.