csc67

Needed to jump start my 89 vette in the parking garage and asked one of the attendants if they had jumper cables. He pulled his car next to mine and placed the cables on his car, then handed them to me. I put the red handle on the positive and attached the black handle on the alternator bracket and a HUGE spark was created. The parking garage guy then says, "oh, I put the red handle on the negative and the black handle on the positive. Car still won't start, windows, radio, stereo all non functioning, even with a tow truck battery trying to start her

Any thoughts on what damage might occur from reversing the cables on one car??

Guess I'm partially to blame, but I never thought I had to check to make sure he connected them correctly

CentralCoaster

If it was really quick, maybe no harm done except for some arc welding on your alternator bracket. How long was it on there?

Maybe it still won't start because your battery is still dead?

If the battery is really low, assuming it doesn't have a bad cell, you may need to let the other car charge it for awhile. Or hold the throttle up on the other car while cranking, this will dump more current into your system.



I've seen 6 optimas up in series and used to weld using tent stakes for welding rod. That's really no different than what you did.

zr1fred

Quite possibly a shorted or open battery.

CentralCoaster

Actually, check and see if the ground strap is still making good connection. The battery grounds to the chassis, which goes to the motor through that ground strap nearby. All this took that huge current you put to it.

TRACKMAN2

JUMPED MY 2000 SILVERADO WITH MY 2006 3500 4X4 BOX TRUCK AND COULDNT FIGURE OUT WHY THE GRILL ON THE 2000 WAS SMOKING ? UNTIL I NOTICED THE PROBLEM OOPS! BOTH ARE FINE.

jfb

You can do a lot of damage with reverse polarity. You can damage the diodes in the alternator. You can damage the ECM. You can damage the cluster. You can damage the heat a/c control head. You can damage the blower control. You can damage the radio (if it was on). You can damage the ABS computer. You can damage the spark module.
NEVER EVER put reverse polarity on your electrical system !!!!!!!!!!!!!!!!!!
Before you jump your car, determine if the jumper cables are correct polarity. With the helper car engine running, let it charge your dead battery for at least 5 minutes, and then try a crank. I hope you didn't damage anything in your vette.

jhammons01

If your battery is [b]dead[/] and I mean dead as a door nail and you pull up with Wal-mart jumper cables then there may be a chance that not enough voltage is reaching the Starter.

Picture the lead inside the battery allowing little pieces to break off like Ice from a huge glacier (just a visual) pretty soon enough lead breaks off and with these little avalanches form one side then another.........soon the lead connects at the bottem of the battery and you have what is called a Dead cell or it shorting itself out. You'll never get that battery to take a charge. Nro will your car start with flimsy cables. A tow truck with massive cables can get enough voltage to the starter and then the Alternater can take over but don't turn it off.

You need a new battery.

Or if your are so inclined.....

You can take the battery and dump all the Electrolyte out of it (Illegal) and then take a hose with a sprayer and shoot the water up into the battery flushing out all the loose lead. Then replace the Electrolyte with new......But for $40-$60 bux, I'd just buy a new battery.

jhammons01

Oh I almost forgot...you'll like this one.

When I was a kid I worked at my uncles VW dealership. When I was about 13 or so they told me to charge the battery on this Audi. I looked the shop unitll I spotted the Charger. A large box on wheels with big cables and and those large clamps that you squeeze to open.

I hooked it up and turned on the timer. Well In a short period of time the car started smoking. The Shop lead "Jay" came running over and pulled the positive off really fast!

He asked me why I hooked the "Arc Welder" to the battery

Doh

Don't worry the car was fine. I just allowed some of the "factory" smoke to escape from the Wiring Harness. If you know anything about European cars they have plenty of Wiring harness smoke...they let it out all the time. A guy on Ebay sells a jar of "factory" Wiring harness smoke for replacement if you let all yours out and your car won't run anymore!

CentralCoaster

Are we sure thats whats happened though? He still had his battery hooked up.

Basically, he just hooked the other guy's battery up in series to his vette. The black cable then had 24V on it (or maybe 20 due to his weak battery). And he touched this to his alternator bracket. This caused a huge current to run from the alternator bracket through the motor ground strap and to the battery ground terminal. I don't really see this backfeeding into the car's other circuits. Especially since most of them are disconnected with the car off.

If he had the key turned on during this, there could be some serious damage like you say to the solid state stuff.

My99Vet

That was hilarious. A mix up at my dad's shop was just as bad. I was 6 y/o and I had to fill the grease gun with a new tube of gold seal grease. I couldnt get the whole tube to fit in the gun, so I placed the remainder in an empty GOJO hand cleaner tub and placed the lid on it. Four days later a customer walks up with gold sparkling arms and says "How do you get this soap off". My dad knew that it was somehow connected to me.

jfb

No, you are wrong! When you jump a car battery you are connecting two car batteries in PARALLEL, not in series. A charged battery connected to a discharged battery and done so with reverse polarity puts reverse polarity 12v on your electrical system and modern cars have lots of electronic circuits with integrated circuits and transistors and they do not like reverse polarity applied to them and can easily be destroyed !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

SJW

This is correct. Although I hope it doesn't turn out this way, the OP is probably going to have to replace some parts associated with the items that he listed as being inoperative.

Be well,

SJW

CentralCoaster

When you hook them up correctly they're in parallel. This was not the case. Your grounding the other car to what is 12V on your car, so the positive on that car is now 24V relative to yours. Make sense? Of course, the dead car will be less than 12V. Maybe 6 or 8v.

Regardless, it can't damage a circuit that doesn't have a path to the positive terminal

jhammons01

^^ I have tendancy to lean toward CC on this one. When you turn the key off you in essence "short" the circuit between the electrical component and the battery. Now some things have a memory circuit so I am not sure about them and what would happen with a voltage spike or reverse polarity.

Like I said I am only leaning.

but the fact that they couldn't get the car to start means they weren't getting any voltage from one car to the other in the first place. Cheap little jumpers just can't carry the power.

......ask me how I know

stubbs

I'm not sure if there are any fuseable links on C4's, but if so that could easily be your problem.

zr1fred

Lotsa fuseable links, right by or under the battery. I don't think he hurt anything from arching, but it can cause ALOT of problems with solid state devices, ie. the regulator in the alt. or the ecm. Electro-magnetic discharges, or as we like to say "arching"!

jfb

You are confused. If you connect the helper battery with the wrong polarity, there will be 24 volts from the dead battery to the not-yet connected remaining jumper cable. BUT...when you clip the last jumper cable to the dead battery, the helper battery will determine what 12volt polarity exists across the dead cars electrical system because it is the battery with the highest electrical capacity that prevails and you will have 12 volts of the opposite polarity across the dead car's electrical system and you have the potential to blow to smithereens, a lot of electrical devices.

SJW

With all due respect, this is not correct.

JFB has it right. The polarity will reverse, as the discharged battery's voltage/polarity will be overwhelmed by the charged battery & alternator on the vehicle that's donating the juice. The result will be reversed system voltage in the OP's car.

The only way to get 24 volts into a system with two 12-volt batteries is to wire them in series, with the center connection between the two batteries isolated from the rest of the electrical system.

This is correct. A circuit that was not connected to the battery at the time of the erroneous jump start should have sustained no harm.

Be well,

SJW

flannel_man

Back when I worked construction I jumped a couple near dead work vans with spare 12 guage rolmex wire. Hold it there for more than about a minute and that stuff gets hott! I have a niec set of 2 guage jumpers now

Bigredwing

Hopefully it's nothing more than a dead dead dead battery. But I learned something new from my son who works for a welding shop that services big rigs. Those guys can have lots of computers and other stuff in the cab that is susceptible to damage by high current/voltage. The shop procedures are that before any electric welding is done on the truck the batteries must be disconnected otherwise the computers and other equipment can get fried. It does happen. So if reversing the cables caused an arc on csc67's Vette there is the possibility of serious damage as has been discussed.