lemonlime

Was in a situation where a friend needed a boost to start his car. I do know the basic rules, but what is the correct procedure?

Also, is there any risk to the electrical components in the car?

What would happen in a situation where the polarity is accidently reversed?

dB Don

Need a Boost?
Jump-start Your Battery Properly

Improperly jump-starting a battery can conduct damaging surges of electricity through a vehicle's entire electrical system(such as reverse polarity or a series dead short). Follow these tips for the proper way to jump-start your battery.

* Refer to the owner's manual for instructions from the vehicle manufacturer.
* Never allow an open flame near the battery.
* Cars should not touch each other, and neither vehicle should be in neutral gear.
* Place a damp rag(if ones available) over the battery vent caps (if there are any), and attach jumper cables in the following order:

1. Clamp a positive jumper cable (marked red or +) to positive (+) terminal of dead battery.
2. Clamp the other positive (+) jumper cable to positive (+) terminal of good battery.
3. Clamp the negative cable (marked black or -) to the negative (-) terminal of good battery.
4. Make the final connection (black or -) on the engine block of the stalled vehicle (not the negative post on the dead battery) away from the battery, carburetor, fuel line, tubing or moving parts.

Stand back from both vehicles. Start the vehicle with the good battery(maybe keep its rpms up if needed)--then start the disabled vehicle. Remove cables in the reverse order of how you connected them.

[ March 24, 2004, 11:23 AM: Message edited by: dB Don ]

Chadxton

iTrader: (1)

The guy in the donor car should be in the car and rev the engine up a bit to prevent the engine from bogging. Since my car has an underdrive pulley and won't produce 14V until 1200RPM, it would die. Hahahaha, I had that experience, it was funny.

lemonlime

Its a bit of an interesting situation with the other guy's car.

The reason I ask about the polarity thing, is because my friend accidently reversed the cable polarity on the dead battery. It was left connected like that for at least 30 seconds, util he realized his engine was not turning over at all. (My car was not started while this was happening).

When he corrected the polarity, the car turned over no problem. The jumper cables were left connected for a minute or so, while he was reving his engine at around ~2500rpm. When he disconnected the cables, the engine immediatly stalled. I thought that was weird, shouldn't the alternator be providing enough current to keep the engine running?

Anyway, we decided to give it another go.. and this time, we left the cables connected for a longer period of time. Revving the engine again. This time, when the cables were disconnected, the engine bogged heavily, but seemed to recover, and idled okay. Within 30 seconds or so, while revving the engine, it began to bogg, and stalled again.

Anyway, I couldn't hang around any longer, and didnt want to risk draining my battery with all the boosts. (I have a yellow top, so its not really designed for all of this cranking).

I just heard from the guy today, and apparently he had to get his car towed to crappy tire, and they told him his alternator was toast. Does this sound like a correct diagnosis based on these symptoms? Could having the reverse polarity connected damage the alternator? His battery originally died because he left his lights on. His car is a 96 accent, and he has not had any problems in the past with his charging/electrical system.

Thanks,
Mike

Chadxton

iTrader: (1)

Alternator toast? I agree.

lemonlime

Thank God everything was okay with my car, I was pretty worried when I realized he had the clamps on backwards.

Bigmike216

I agree. That's most likely the problem. If the alternator were toast, then his car would be running solely off the battery.. so removing the cables from a dead battery would cause the car to have no electricity.. and thus stall.

Sassmaster

iTrader: (2)

could just be a FUBAR'd battery... I had that happen once in winter, took 20 minutes to charge the battery enough to get the car to turn over. replaced the battery soon after, and it runs great.

Also, I've heard of newer cars that are unable to boost other cars because the computer can't handle the voltage drop or something. another thing I've heard of is vehicles that can only boost another car once, any more than that the computer can toast itself.

[ March 24, 2004, 04:00 PM: Message edited by: Sassmaster ]

JohnVroom

^ If a battery were to short internally you are correct ...but you will only hear of that happening maybe once or twice in your life (very unlikely unless there is a run of wildly defective batteries).
The symptoms described are textbook for a failed alternator. The rub is a failed alternator will make the battery work overtime and fail with it, conversely a failed battery can overwork the alternator and cause it to fail too. The quicker you say "I have a problem" the cheaper it will be!

JohnVroom

Here is a Q for the guys who work in a car audio shop, wil jumping a car cause a digital piece of equipment to fail?
The new digital power supplies in amps and the digital processers have a more petite design, and can not take voltage spikes. Has this been showing up as a weakness as far as returns go? his is what concerns me when I jump, or get jumped.