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Does Jumping Another Car Harm YOUR Battery/Alt??


solaris=amazing
07-09-2004, 11:48 PM
I always wanted to know this. Does jumping a car that has a dead battery harm your own battery? Or alternator?

I think the alternator charges the battery? Is that right?

Sorry for the simple minded question, thanks.

public
07-10-2004, 04:11 PM
Yes, the alternator charges your battery and provides all of the electricity needed for the engine and accessories like the radio. The battery is only used to provide electricity when starting the car and will keep the engine running when the alternator fails. Some cars also use the battery as a capacitor to even out the alternator output at lower rpm's. Most cars can give or receive a jump with out harm. I have never seen one hurt by jumping, but I have heard that some cars are not supposed to..?? Check the owners manual to be safe.

solaris=amazing
07-10-2004, 04:17 PM
Hey thanks public, did some research last nite, and found out it can seriously damage your electrical system. Something like the alt in the dead car can send to much of a charge back you the good car, and basically screw it all up.

Next week i'm gonna buy from wal mart this 300amp everstart battery charger, it's only 39.99 and can be recharged anytime. Cause the last thing i wanna do is help someone, then I'M f****d. With the charger, you can help people at will.

public
07-11-2004, 08:35 PM
I have heard of this occurring, just never seen it myself.

MagicRat
07-11-2004, 08:48 PM
Hey thanks public, did some research last nite, and found out it can seriously damage your electrical system. Something like the alt in the dead car can send to much of a charge back you the good car, and basically screw it all up.

Next week i'm gonna buy from wal mart this 300amp everstart battery charger, it's only 39.99 and can be recharged anytime. Cause the last thing i wanna do is help someone, then I'M f****d. With the charger, you can help people at will.
The potential for damage only occurs when you disconnect the jumper cables. Rarely, but occasionally there can be a voltage spike that could knock out the diodes in your voltage regulator and affect other systems. But its easy to avoid.
Before disconnecting the cables, turn on your headlights to provide an electical drain, which can buffer the system, or switch your car off, (presuming its the electical donor, and not the recipient.)

Doug Rodrigues
07-12-2004, 12:05 AM
MagicRat is correct. The safest thing to do is to keep the donor engine off. Also, don't let some bozo check for "proper jumper connections" by arcing the terminals like I've seen some people do. That whine you hear on the radio afterwards is a blown diode in the alternator from that arcing.

SaabJohan
07-16-2004, 12:24 PM
Jump starts have also caused damage to the computers onboard the car like engine management.

quaddriver
07-16-2004, 01:31 PM
I dunno, Id think that jumping another car would harm the springs/suspension the most. the only way I figure that the alt/battery can be harmed is if you came down too hard and the shockwave took em out....

public
07-16-2004, 03:30 PM
LOL, Ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha, ough......

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