So yesterday I was coming out of a Christian book store and I lady in the parking lot asked me to use my car to help jump start hers. So, as any good person would do I willing jumped her car. She then said thanks, and dove off. As I'm sitting there and about to leave I'm noticing my HID fogs are not working, as weel as one of my LED parking lights!! Anyone have an idea of what happened?

 

Did you check the fuse for these ?

 

Wow! You are nice i would have started to speak spanish and left! Lol!

 

lol...thats just wrong..lol

 

lol! Was she hot? Then i might have lol!

 

Hey since we're on subject, I was told the car with the good battery should not be engine idle when jump starting because the juice that comes back from dead battery's car can damage the alternator? It kind of makes sense since the dead car just needs battery power to jump start.

 

It's safer for the car giving the jump to be off. If it's running, it could overload the alternator and cause the regulator to burn out. It's not as common now as it used to be though because the electronics are a LOT better than the old days.

There is no such thing as the juice coming back. Electricity doesn't work that way. When you hook up the batteries, they'll attempt to level the charge between them. You may need to stay hooked up for a few minutes to allow the bad battery time to build up charge. Trying to start a fully dead battery from a jump usually won't work because the dead battery is acting like a dead short for the other battery and there isn't enough current available to hit the starter. Even a good battery will drop to 8 - 10 volts on the initial starter contact because the current draw is so high.

Your starter draws ~350 - 400 amps in the first few milliseconds (there are good reasons for this) so your battery has to have reserve to make the starter turn. This is why CCA is such a big deal. If you don't have enough CCA to get the starter turning AND power the engine management system, you'll never get the car started.

So after all this - it's possible your system suffered a voltage drop as a result of hooking up a dead battery to your live one. Did you leave your car running? If you did, shame on you for hurting your car unnecessarily. If you didn't, there's no good electrical reason why you should be seeing issues.

 

i was getting gas at a mobil station one time, and a guy got out of his beat up pick up. needless to say he too needed a jump start. for some reason i was thinking "hell no", but im always willing to lend a helping hand. his truck ended up needing a new battery all along, so it was actually useless. i did notice that the lights do flicker a little since then. prolly gonna take it to the lexus dealership later, but it might just be me...

 

hm.. interesting to know... i never had problems by jumping other peoples car but... i should be more careful from now on
Thanks for sharing..

 

yes, my car was tuned on. So what do I do now?

 

I did it last week for a co-worker that had a completely dead battery and I had no problems. I had my car runing as I do all the time when I help with a jump start, her car didn't start at first, but after a couple of minutes the second try worked fine.

 

I've never jumpstarted anyone and don't plan on doing it any time soon. When people approach me (which is rare) I usually tell them that the battery is not easily accessible and that I'm in a hurry.

 

[QUOTE=lobuxracer;4834919]
Your starter draws ~350 - 400 amps in the first few milliseconds (there are good reasons for this) so your battery has to have reserve to make the starter turn. This is why CCA is such a big deal. If you don't have enough CCA to get the starter turning AND power the engine management system, you'll never get the car started./QUOTE]

What is CCA?
Good post btw, I wish there was a way to 'nominate' it.

 

[QUOTE=vraa;4835738]Cold cranking amps.

 

I hope you never need a jump start, what goes around comes around...