Stormin Mormon wrote:
A caution when using 12 volt boost. Please don't
wiggle, move, or unclamp the terminals when using
boost. I did see an old farmer explode a battery
one time. Using boost, and then squeezed one of
the charging terminal clamps. The resulting spark
lit off the hydrogen. It sounded like a gun shot.
I may never forget the next words "get some
water for my eyes."

Unplug the charger and wait a couple seconds before
wiggling or removing either of the cable clamps.

That's why they tell you to attach the ground terminal LAST to a grounding point
away from the battery, and remove that first. It doesn't take a boost charger to
generate a spark.