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.

You have a bad connection at the positive post, either wire to terminal, or terminal to post. Clean the posts and terminals with one of the battery post brushes. Lots cheaper than a new battery...

I did clean them just last week...
Sorry I don't know the terms here, but the bridge piece between the positive terminal and the small fuse box seems to be a problem area. Do you suggest using any of that battery grease anywhere, or just leave it dry after cleaning it. Why would it 'pop' like that? Thanks

OK, then it's the condition of the connection between the battery terminal and the conductor that bolts on to it and goes to the fusible link box. It carries the juice for the whole car except the starter. Bet the brake lights at least were on? Maybe the fan? For sure the starter solenoid was drawing juice. Enough current to pop a good spark. Dielectric grease is your friend on any bolted electrical connection, 'specially around batteries. Clean up the contact surfaces with a wire brush and grease 'em up and bolt them tight.

Lead acid batteries liberate hydrogen gas when overcharged. Normally this dissipates quickly and isn't a problem unless there's a spark nearby. Loose/dirty cables/terminals might cause a spark, but you said they were tight. <img src="/forums/images/graemlins/confused.gif" alt="" /> You might want to check all the connections again and clean them like fasteddy said.

Fixed! You were right--it was dirty.
Thanks--the people on this forum are the best. Taking the time to answer my noob questions I'm sure is low on your priority list, but you saved me $60 by doing so. Thanks again, and happy holidays!

Mitch

Nice! But you deserve credit too, for following the advice, and then following up with us! <img src="/forums/images/graemlins/cheers.gif" alt="" /> Kudos to all! <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

the same thing happened to me 2 years ago and took me a while to figure out that it was just dirty....I went more than using a a wire brush though, I used some emery cloth and got to raw metal before I bolted it back on...good as new after that.