Did I ruin my battery charger?

Probably ruined. Some have reverse polarity protection and some do not. XTAR is a good brand. You might check them out and see if they work with your batteries. I'm assuming some sort of lithium batteries. If they are, I'm not sure I would try to reuse the batteries, either.

You might check out candlepower forums. Some of those guys really know batteries. Be sure to tell them what kind of battery you have.

hey thanks for the quick reply. I figured the charger was ruined. the batteries are just regular lead acid deep cycle. I guess I need to buy a new charger/inverter. the one I had was sweet too. at least now I finally got the back/red positive negative thing figured out.

Oh. Lead acid batteries might still be good. Still, I would stay out of line of sight during their first charge. I'm a little paranoid about small packages with that much available energy.

Good luck, and I bet you never do that again.

Certainly sounds like it.

Buy a new one. They're not that expensive.

Also, how the hell can you possibly plug it in backwards without really having to force it? Those sorts of electronics are designed with enough difference that a connection can only go in one way.

you can put the batteries in backwards.

Yeah, I suppose you can. I stand corrected.

I think what you thought was they plugged the charger in backwards. That you can't do.

I was thinking it was a phone charger or an iPod charger. They both have plugs and slots that make it impossible to do things in any way other than the correct one.

No, I think they just swapped poles on the batteries.
And phones etc. don't use lead-acid batteries.

Also SPAM batteries can get ruined this way.

Yea I hooked the charger cables to the wrong battery posts. I think its strange that it seems like the charger is working but the battery voltage actually starts going down slowly instead of going up. The inverter still works I think.

The charger is a Xantrex Freedom Hf 1000 Inverter Charger, they run around 400-500 dollars. so it was a pretty expensive screw up.

Ah, I just Googled it. So it was cables. Gonna bow out now; this is out of my league.
http://www.xantrex.com/power-products/inverter-chargers/freedom-hf-newgen.aspx

Ditto here. I wrongly didn't think it was an automotive charger that was being discussed because it was not stated as such up front. Shame on me. Car/ trucks/boats are lead-acid batteries. I had thought of a small electronics charger.

To the OP:
If you didn't observe polarity, causing a short w/ arcs and sparks and your battery isn't charging, then it sounds like you may have damaged the charger.

Generally speaking in a car or truck, the positive terminal is marked with a plus, negative minus...Battery charger cables are generally red for positive and black for negative.

Yep. And I immediately assumed we were looking at some kind of lithium battery. Reverse polarity on those things can have unhappy endings. We all should have asked for clarification.

Weeping in my beer