craigm1841

I originally thought that... but there is a big current draw when you turn on your Air and nothing happens. i wouldnt draw current from the car if it wasnt running, but running this should be fine. i mean, a 12V battery fluctuates voltage depending on ambient temp, life cycle, your battery pushes anywhere from 11.5 to 13.5 volts at any given time

ktlocklear

Yeah, that was my concern......how about jumping with the e60 turned off??
The other car is a 4 banger, and it's not completely dead....around 9.5-10 volts. It should crank with just having the cables hooked up, without the key even in the e60

craigm1841

situation. You walk out of a store, there is a gorgeous girl in the parking lot next to her broke down car. it wont start, she left her headlights on... she is standing there with jumper cables and she asks for your help? you say:

1) sure, let me get my car?
2) sorry, I have a bmw and I dont think it is made to jump other cars
3) sorry, I dont know how to do that from my car
4) i am a jackass, also known as answer 2 and 3.

I cant imagine your bmw not being able to jump another car.

craigm1841

dont jump with the car off. 9.5-10 volts??? man is that thing stick? pop the clutch on it. you could cause problems changing your voltage with the car off. BTW, sometimes 4 bangers require more cold cranking amps (CCAs) to start. size of the engine has no bearing on whether you should try to jump it or not...

ktlocklear

I could pop the clutch on it...didn't even think about that.....the battery is an Optima Red Top, and is only a few months old. I think the CCA's on it are 750? I only drive the car maybe 1-2 times a month. I need to just disconnect the battery from now on I guess, once I get it charged up again.
Maybe I'll just wait and use wife's suv to jump it when she gets home, just to be safe

craigm1841

pop the clutch brother. put it in second gear and jump in and dump that clutch. sucker will fire right up. (make sure the key is in the on position)

ktlocklear

Yeah......popped the clutch many times over the years...never an issue. My only concern is the driveway is super steep, which will help, but if it doesn't fire up, then I've got a car stuck out in the road

craigm1841

yeah, unless you recently competed in the worlds strongest man competition, you be screwed. that is such a slight dip in power, maybe try some distilled water in the cells. unless you cant because its an optima... i am vaguely familiar with optima. is that the gel cell?

i would jump it if it is an emergency, otherwise wait and use the ladys ride.

luigi524td

WHOA ... did you say her highbeams were on!

Jump her ooooh her car ...

Ok ... now let's get serious about this. I've used my BMW's to jump start cars in the past. However, you MUST be sensitive to any transient voltage spikes that might occur and potentially harm some very sensitive electronics - ON EITHER VEHICLE [the jumper or the jumpee] !

I would say, to be on the safe side, with BOTH vehicles turned "off" to connect the jumper cables at (+) terminals on the batteries or on BMW's the jump post under hood and (-) cables to a good earth/ground location [bare metal on frame, etc]. Once again, on BMW's many have what looks like a large bolt on the suspension towers. Allow the good car to run for 10-15 minutes as a fast idle. At that point, turn off BMW, disconnect cables and try to start the dead car.

That may give just enough juice to get things cookin without possibly having a current surge feed back into the BMW as mess with sensitive circuits.

The other alternative are to carry one of those portable battery gizmo's that most road service trucks use nowadays. That minimizes having to park right up to a car to connect jumpers.

EBMCS03

Well have you jumped her yet? I mean it yet? I want to hear what happened. Car working still fine? or do you have errors now?

Dude just goto Kragen or PepBoys and buy a Jump pack... $25. and you can have it around the house or trunk of the car.