Okay, so it didn't explode, it was more of a loud pop with a fist sized spark.

92 Montero, 3.0 engine.

Battery was drained, I trickle charged it and it worked fine after that. Now, I let the missus drive it for a day and have to rescue her 2 times. It seems the terminals are terminally loose.

I took a few days off from driving it, and it sat in the garage. Fast forward to last night, I tried to start it--nothing, just a clicking. Checked the terminals, and the neg terminal was loose. I tightened it down and tried again. My wife turned the key while I watched. It clicked, and then made a loud POP, complete with sparks, at the Positive terminal.

Suggestions? I'm going to buy a new battery today unless you guys can dissuade me.