reversed polarity - Help!

cisco06430 · 03-20-2005, 06:51 AM

996 sitting in barn all winter... battery completely dead. Being blond! I connected the charger incorrectly (+ to _ and - to +). I did disconnect the battery from the car first, then reversed the polarities and charged. I connected the battery back to the car (which made sparks fly at the 2nd pole)... Nothing else visibly happened to the car (no lights, no nothing). Figured out what I did wrong, disconnected the battery from the car again. Now I tried charging correctly...not working. The charger keeps tripping. Now what? Is it highly likely I already damaged the electrical systems in the car OR did I merely reverse polaritry of the battery since it was completely dead before? Or both? The battery charger manual says it is polarity protected, but I figure that only works if there is juice in the battery to begin with? What would be my next logical step be? A new battery? Any help from you folks will be greatly appreciated! If you tell me to check all the fuses, what does a 'bad' fuse look like...yet that step probably comes after having a working battery attached to the car. OOOHHHHH what a crummy day!

Thanks!!!

FrayAdjacent911 · 03-20-2005, 07:22 AM

I think you'd be needing to get a new battery.

Though, honestly, I don't know what would happen to a battery if you charged it with the polarity reversed, but I can surmise, it's not a good thing.

I'd be more concerned about the electrical system in the car. You can always get another battery easily.

Remember: ITDCCVSR (inattention to detail can cause very serious repercussions)

Gunter · Gunter's Garage

I don't think you did much damage to the system. If the battery is less than 3 years old, take it to a shop for a power charge, they will tell you the condition of the battery. If you need a new battery, get the right leak-proof one for your car. In the future, when you store the car, either put a battery maintainer on it, or remove the battery and use a trickle charger. Also, search this board for the correct way of storing your car; many useful directions here.

ZOA NOM · ZOA NOM's Garage

Check all your car's fuses.

john walker's workshop · 03-20-2005, 11:40 AM

with all the electronic stuff on that car, i wouldn't want to be you. either get a fresh battery, or figure out how to draw the voltage back down to zero and recharge it properly. then find out how lucky you are.

Britwrench · 03-20-2005, 11:44 AM

It's probably blown the alarm system fuse (which is in the control module under the seat).

As John said, just go and buy a new battery (Interstate MTP91). Also get the Schumaker battery maintainer and bolt that in. Batteries going dead on modern cars is not good.

bell · bell's Garage

you need to go through all the fuses, every single one.
chances are every cirquit with a direct battery feed blew the fuse and hopefully that's it, i've seen worse.....

but if the battery/charger was never hooked up the the car (you said the batt was unhooked) then there is probably no damage other than a fried battery, it's when polarity is reversed and the battery/charger is hooked up to the car when big damage can happen.

john walker's workshop · 03-20-2005, 12:50 PM

it was installed momentarily, with a reverse charge on the battery.

ruf-porsche · ruf-porsche's Garage

Fuse don't blow just because you hook up a battery backward or charge the battery backward, what do blow are diodes and other delicate (Expensive) electronic parts that can't take a reverse current.

The radio could be blown since radio has current going through it just to maintain the preset.

If the poles are reverse in your battery, + is now - and - is now +
and you did hook up the reverse battery to the car as a normal battery I think that some of the delicate electronics in the car are now damaged.

SLO-BOB · 03-20-2005, 01:46 PM

Didn't know you could reverse a battery's polarity. I've been in the electrical contracting biz for 15 years and I learn something new!

I would start with a new battery.

Britwrench · 03-20-2005, 02:00 PM

We had a customer's 964 bought in where the jump cables had been reveresed and that blew the ABS fuse and did no other damage.
A Boxster had a similar situation, that blew the alarm and radio fuse. No other damage.
That's not quite the same as reversing the installed battery, problem is without a new battery and connecting the Porshe PST2 or 3 tester, it's impossble to really know what is damaged.

real550A · real550A's Garage

A dead battery will charge either way, but once it's been reversed, they're done. You can short it out and start over, but auto type batteries don't respond well to complete discharge, let alone opposite charge.
Start with a new battery and see what you've got.

john70t · 03-20-2005, 05:21 PM

Probably quite a few things damaged as the newer cars may have multiple computers(especially cabriolet/convertables). Just be glad the battery didn't explode in your face, it's happened.

New battery, installed correctly, and go from there.

cisco06430 · 03-20-2005, 09:36 PM

Thanks for all your advise.
Battery was new.. 1 year old.
Will uninstall and get a new one. The charger did have a reverse polarity security switch, but since the batt. was completely dead, I think this little feature did not trip and reversing polarity is then possible.
Will check all the fuses and hope for the best.
Let you know how this little adventure to turns out.

cisco06430 · 03-21-2005, 04:27 AM

I got to be the luckiest brat! New battery is in...EverYthing WorkS

. Fredchen is humming and happy & me too

. Had the 'old' battery checked...yeap I managed to reverse the polarity on it. Oh the only fuse that was blown was the one to the radio... Thats all folks! Thanks for ALL the advise...it really helped me make it thru the weekend without tripping totally. Now where is the nearest track? Hehehe
Will take the car in to have the computer checked, just to make sure

& make Porsche happy.

Fredschen: 99 996 C2 (out to play)
Emma: 03 540iAT (in the barn for the summer)
Rocky: Barn Guard Dog