kaboom goes the battery

[dungY]

had a battery explode on me today
needless to say it was pretty scary
we were driving to our chicken houses, stopped then went forward then boom.
could this be to an upgrade in my controller calling for more amps? (alltrax 400)
or maybe coincidence with a battery just starting to go south.
we were running around our farm with outside temps ~38 degrees f
any thoughts?

[RobCons]

A quick internet search leads to exposed plates, the off gassing of hydrogen while the battery is being discharged, and an arc between the exposed plates. There are some really knowledgeable battery folks on here that can make a much more educated deduction. Glad you are ok.

[scottyb]

Batteries produce hydrogen gas. All it takes is a spark. That can be from an outside or inside source.

[csport]

Hey I got a riding lawn mower battery to blow about 14 feet high and land on the garage roof
I think It took me two weeks to get most of my hearing back-

so the rule, unplug your charger before you take it off the battery is a extremely valid statement!

and I wasn't allowed to play with any tools for a week without other adult supervision

[scottyb]

What happened here is pretty rare, It sounds like a loose or weakened plate connection that produced a spark. Batteries still holing a fairly fresh charge would have gas in them. Glad nobody was injured ...

[Bill]

Ouch, nasty.

Mix up some baking soda and water and wash all that acid down then rinse with water. Then remove battery's- wash rinse repeat...

Usual safety stuff- watch your eyes, skin etc and try not to spray directly on electronics, switches etc.

[JohnnieB]

Looks like the initial explosion occurred in the end cell, which in turn, took the top off the middle cell. The hydrogen gas in the middle cell may have been ignited by the heat of primary explosion, but the top was off by then, so the fireball wasn't contained and no secondary explosion occurred.

Fortunately, each cell had a separate vent cap, so only one cell exploded.
When all the cells in a battery are connected via a single vent cap and when all the vents in a battery pack are connected together via a watering system, chain firing can occur.

--------
The fact you recently upgraded to a higher ampacity controller is coincidental.

--------
Whenever an electrical current passes through the electrolyte, electrolysis of the water in the electrolyte occurs, so there is both hydrogen gas and oxygen gas in the airspace above the electrolyte in the cells whenever the batteries are being charged or discharged.

Hydrogen concentrations over 4% and under 74% are flammable and if the fireball is contained, you get an explosion.

-----------
Like others have suggested, neutralize the spilled acid with a baking soda solution and rinse thoroughly.

Glad that nobody was injured.