Watched a coworker try to jump a big block Cummins with a Ford Focus battery last Tuesday

The Focus battery lasted about 3 seconds before it swelled up like a balloon and popped the case. We had to wait 45 minutes for a proper boost truck to show up because nobody else had cables long enough. Has anyone else seen a battery fail that fast or was this just a record breaker?

2 comments

2 Comments

the_river10d ago

Held my breath watching that battery swell up... can't say I've seen one pop that quick though. Must've been some serious current draw from that Cummins. Probably would've been smarter to just push the truck downhill rather than watch that battery explode.

cooper.reese10d ago

Yeah but nobody's talking about what happened right before that battery went. Watch the video again, that alternator was screaming like it was about to throw a bearing. Those Cummins alternators can push some serious amps when they're hot, especially if the voltage regulator is cooked. I've seen a few of these where the batteries actually got backfed through a bad ground and that causes them to gas out fast. The whole setup looked cobbled together too, zip ties and speaker wire wrapped around the terminals. You can almost smell the poor decisions before it pops.