I saw a fat kid sit on the hood of a Datsun pickup and short the battery terminals. It when BOOM! When we opened the hood, the battery was cracked down the middle. Another time, my bro-in-law hooded up jumper cables backwards and the battery split in two.
I bought a battery minder like charger from Interstate, for about half the cost, but it does not have the desulfation mode. I do have two other chargers that will do that, if needed. I took my battery inside when it got below 20.