Jump starting - which manual is correct?

[Brucelee]

Originally Posted by MNBoxster

Hi,

You should connect Positive from problem car to Positive terminal of the Donor Car, then Negative from Problem Car to Negative Terminal of Donor Car. But, you should not have the Donor Car running, you want to jump straight from the Battery...

Happy Motoring!... Jim'99

what Jim said.

[HIFI]

Thanks for the input, can someone look at their Porsche manual and see what I'm talking about? Nothing is hooked up to the negative lead on the good battery and the bad battery's negative goes to a grounding point. Is there just more than one way to jump the car correctly, or is Porsche wrong?

Also, how long do I leave the 2 not-running cars connected before I try and start the dead Porsche?

[wild1poet2]

I just saw this thread. The reason some advise connecting the negative to a ground is to avoid the situation where a spark from connecting to the negative terminal on a battery ignites combustible gases from the battery. There have been cases where batteries have exploded into peoples faces. But sometimes you cannot get a good ground a you just take your chances and connect to the negative terminal. LOL The Porsche manual also has to consider legal liability.

Originally Posted by wild1poet2

I just saw this thread. The reason some advise connecting the negative to a ground is to avoid the situation where a spark from connecting to the negative terminal on a battery ignites combustible gases from the battery. There have been cases where batteries have exploded into peoples faces. But sometimes you cannot get a good ground a you just take your chances and connect to the negative terminal. LOL The Porsche manual also has to consider legal liability.

Ditto. That is correct. In addition, a running donor car was a must a few times I jumped a dead car. The good battery alone didn't have enough juice to turn over the car from the dead battery. I recall the alternator squealed some, and took about 3-5min to get a good enough crank. I would surmise that without the alternater, some really drained batteries would never trickle enough juice from the charged battery to start a car in some situations (very cold outside, or big block, etc...). So while I respect Jim's opinion, I don't agree with him.

[wild1poet2]

I checked my manual and it actually says to leave the donor car running. I have an '04 so maybe the protocol is different depending on the year.

Also, when I jumped my car today I attached the negative cable to the chassis for ground. Didn't work. So I adjusted the connections, still no good. I gave up and just went old school and attached directly to the negative terminal on the donor car. Started right up. LOL

Thankfully I didn't need a tow and I didn't need to jump the fuse box to open the trunk. I got it to the stealer and asked them to do a load test on the battery and check the charging system for me. Hopefully its just a bad battery. But boy it went bad in a snap. It happened to me once years ago on my harley when a 4 month old battery went bad. Like all of a sudden bad. So I guess it happens. LOL

[racer_d]

I think its hard to find a true ground near the boxster battery (just theorizing as i haven't really inspected the battery area) because of the cars high aluminum content. You need a nice "real metal" ground, or the negative pole of the battery.

I've never started a "dead" car without the donor car running and providing a charge to the dead battery. Usually let the donor car run a few minutes before trying to start the dead car.

How old is the battery that died? Do you know why it died? How was the "water" level in the dead battery? Given age and climate and use, it might be time to get a new battery. You'll know for sure that first cold fall morning when the battery is dead again

[wild1poet2]

racer d ....I did end up needing a new battery.

My car is an '04 which I bought as a "leftover" in late '05 when the new '06's were coming in, and the dealership wanted to move it off the lot. Hence, I bet the battery probably discharged while sitting there all that time waiting for me to come along. I keep it on a battery tender during the winter.

Anyway, I jumped the battery and took it to the dealer to be load tested and to have my charging system checked out since I wasn't sure what killed the battery. I did not remove the battery so as to preserve the trouble codes.

They took my car right in and withing a few hours it was all set to go with everything reset. But the $311 charge really shocked me!! That is the most expensive battery replacement I have ever incurred. LOL