What's the damage?

June 10, 2007 10:50 PM

A friend and I were charging the battery of a 2001 Honda Odyssey. He attached the cables to the wrong terminals of the dead battery. How much damage might we have done?

There were no immediately observable results from this screw-up except that the horn went off when the last cable was attached. No explosion (thank God), no smoke. But the battery certainly doesn't show any interest in charging now.

I'm pretty sure we (at least) blew the battery fuse. Changing that out didn't seem to help, though. Googling doesn't give much info besides "please don't try this on my car" and "attaching the cables to the wrong terminals can cause irreparable damage to the battery and other parts." (What does that mean?)

So--I'll get a mechanic to look at it tomorrow, of course. But I'd like to know, from any of you mechanically minded mefites--what's the possible damage? Thanks.

posted by torticat to Travel & Transportation (8 answers total)

I wouldn't worry too much about damaging the battery ... a mechanic should be able to reverse that with a pro charger.

As for the other circuitry in the car, it's hard to say ... depending on how/whether Honda protected the circuits from reverse polarity. I'd guess that they expect that to happen.

Here's one example that turned out pretty much ok.
posted by Twang at 11:55 PM on June 10, 2007

Same car, same problem, mechanic's answer. In short: hope it's the fuse.
posted by robcorr at 11:58 PM on June 10, 2007

Best answer: I think you could be spending more money than you have to. Instead of taking it to a Mechanic, simply go buy a new battery and install it.

If everything runs, seems to me you're in the clear and saved some money to boot.
posted by crewshell at 12:04 AM on June 11, 2007

Ditto to crewshell. Likely no damage, replace the battery, and all will be well.
posted by spitbull at 4:08 AM on June 11, 2007

Replace the battery, obviously replace any blown fuses (they're easy to see) and then go for it. There may or may not be a relay directly downstream from the battery that would need to be replaced too if you popped it. The mechanic would do the same thing: shrug, put a new battery in place, if no workie go to step 2 and replace fuses, ... if no workie, go to step 3 and replace the relay, if no workie go out for a beer and post to Ask Metafilter.
posted by SpecialK at 4:10 AM on June 11, 2007

Yep, just replace the battery and try starting the car. I have done the exact same thing with a charged battery and nothing bad happened. As long as the key wasn't on there should be no problems.
posted by peewinkle at 6:14 AM on June 11, 2007

If the battery already had a problem such that you felt the need to charge it then it might have already been croaked. Most auto parts stores have free battery testing. The only downside is you've got to yank it out and lug it in. Well worth it to save unnecessarily spending money on a battery.
posted by phearlez at 8:14 AM on June 11, 2007

Response by poster: Advice taken: new battery installed, fuse replaced. Problem solved, as far as I can tell. Yay!

Thanks all!
posted by torticat at 10:45 AM on June 11, 2007