Discharged Battery, 89 Carrera 3.2 - Jump it? Compression start it? Charge it?

[mmm]

Well darn it. I let my battery run down a bit too much apparently. Engine just barely starts to crank but not enough to turn over.

Don't have my owners manual handy. So:

1. Can I compression start it like any other manual transmission car? Or is that inadvisable somehow for a 911?

2. Access to the battery terminals is pretty tight (too tight I think) for my charger clamps under the front hood unless I remove the battery I think. I should know this but are there auxiliary terminal points anywhere else for battery charging? I know you're not "supposed" to do it in the car but....

3. What about those running a charger through the cigarette lighter like I sometimes see, bad idea?

4. Anything else?

Pretty sure everything is otherwise fine w/ the car.

[Canada Kev]

The positive post is relatively accessible, so you should be able to place a jumper there, and then you will likely be able to place the negative cable on a grounding point. I believe you have one at the edge of the trunk about a foot behind (closer to the driver) fuse panel.

Or just yank your battery and charge it out of the car.

[John W.]

I'd just charge the battery. The cigarette lighter charging is only for trinkle charges since the wires are NOT made to handle high currents.

[mmm]

Originally Posted by John W.

I'd just charge the battery. The cigarette lighter charging is only for trinkle charges since the wires are NOT made to handle high currents.

2 amps too much?

[mmm]

Originally Posted by syzygy

The positive post is relatively accessible, so you should be able to place a jumper there, and then you will likely be able to place the negative cable on a grounding point. I believe you have one at the edge of the trunk about a foot behind (closer to the driver) fuse panel.

Or just yank your battery and charge it out of the car.

Well, I'm not sure if this is proper but the battery, a NAPA unit, is installed with the terminal post side up against the wall of the trunk, so up against/towards the wheel well side/wall, with the negative towards the front of the car nearest the front bumper and the positive harder to reach at the rearward end where it's more "tucked under" and not very accessible.

What about just compression starting it and then driving it around for a while? Driving it around for a while is ALWAYS good, and I live on a bit of a hill, so I think it should be doable. Or is that not a good idea for some reason, beyond the risk that it won't start by the time I reach the bottom of the hill I mean....

[Larry_Ratcliff]

is the carrera somehow different than an SC for battery placement? SC battery is very accessible. For an SC I would have answered any of the above. Jump it, push start it or recharge it... I have done all but the push start.

[SteveinTO]

I've bump started my '82 without any adverse effect. I'd do it in 2nd gear. Might be a little more difficult cold.

If you have the time, I'd just disconnect the battery terminals, remove the caps, check the electrolyte level and, since it isn't deader than a doornail, put 2 amps into it over night. See what you have in the morning.

[mmm]

Originally Posted by Larry_Ratcliff

is the carrera somehow different than an SC for battery placement? SC battery is very accessible. For an SC I would have answered any of the above. Jump it, push start it or recharge it... I have done all but the push start.

No idea, but as it stands I don't think I can get my charger clamps on the terminals in place.

[mmm]

Originally Posted by SteveinTO

I've bump started my '82 without any adverse effect. I'd do it in 2nd gear. Might be a little more difficult cold.

If you have the time, I'd just disconnect the battery terminals, remove the caps, check the electrolyte level and, since it isn't deader than a doornail, put 2 amps into it over night. See what you have in the morning.

Hell, I'm almost wondering if it wouldn't start as is at a slightly warmer temp. It's seems so close. But odds are I've let it go just a bit too far....

[snbush67]

I don't think you can bump start it with no juice in the battery it will not run the fuel pump or the injectors.

[mmm]

Originally Posted by snbush67

I don't think you can bump start it with no juice in the battery it will not run the fuel pump or the injectors.

There is juice in the battery, just not enough to crank enough to start. Once rolling the alternator can power the fuel pump and injectors as well I think. That's how compression starting works, get the alternator turning and viola juice! Or at least that's what I've always understood.

[efhughes3]

Jeez.....push start it or pull the battery and charge it. These cars aren't that fragile or quirky.

[snbush67]

Maybe if you humm methodically at different ranges and mix it up with some whale mating sequences you could sonicly start something, I would only pull the battery as a last resort, like if oompa loompas were trying to dry hump your dog or something.

[911pcars]

Don't use the fragile alternator to recharge the battery. It'll shorten it's life.

To conveniently attach a charger w/o removing the battery, attach the positive charger lead onto one of the constant source wires in the fuse box (usually w/red color code). Confirm with a voltmeter or test light. Like the cigarette lighter, such a circuit eventually connects to the positive post of the battery. Make sure it's a low amp trickle charger though.

Sherwood

[dad911]

If you are in no rush, just charge it. Better for the battery, and alternator.

[mmm]

Originally Posted by snbush67

Maybe if you humm methodically at different ranges and mix it up with some whale mating sequences you could sonicly start something, I would only pull the battery as a last resort, like if oompa loompas were trying to dry hump your dog or something.

I tried that. No dice. It did scare the oompa loompas off from humping my dog however, so that was nice.

[herr_oberst]

Get a small pair of needle-nose vice grips (6" size) to throw in the tool kit. When you need to jump the car, clamp them to the positive post for a little extension for the jumper cables. (The Harbor has some cheap-charlie vice grips that are perfect for this purpose)


mo

[911pcars]

Originally Posted by herr_oberst

Get a small pair of needle-nose vice grips (6" size) to throw in the tool kit. When you need to jump the car, clamp them to the positive post for a little extension for the jumper cables. (The Harbor has some cheap-charlie vice grips that are perfect for this purpose)

mo

Errr. You may want to insulate all but an inch on either end of any tool used in this way. Imagine a locking plier, firmly clamped to the positive post, wandering over and making contact with the chassis (ground). This would make for one interesting light show.

If you must have access to the positive battery post, install a remote battery terminal adapter and a positive post extension cable connected to it.

Bulkhead mounts, cable-to-cable:


Bulkhead mounts, cable-to-post:


While not statistically valid, check the archives for the number of dead alternators who, in their previous life, were allowed to recharge a dead battery. While it may not happen the first time, the practice will eventually shorten its service life. Use this procedure sparingly if at all.

Sherwood

[mmm]

Eureka, found a solution.

Went to Home Depot and bought some 10 amp rated alligator clips that are small enough to fit over the threaded ends of the battery terminal bolts. They fit on spring loaded nice and tight and then I am able to clamp my larger charger clamps onto them.

Got me a nice little 2 amp slow charge running to the battery in car as we speak.

[seafood10]

Great...now the oompa loompas are humping my Labrador.......must be because my battery died as well today and Costco didn't have a new one, oh well.