is it safe to Jump the coupe?

[schwank]

Hi,
I seem to have let my M's battery die over the winter. I remember it was getting weaker in the fall (I did start it every few weeks over the winter).

Is it safe to Jump it? Id like to see if she'll hold a charge, but Im not opposed to just buying a replacement battery (she's out of warranty as of about a week before parking her for the winter).

Thanks!

[mhughett]

Yes, but make sure you use the designated posts that are UNDER THE HOOD and not the battery itself. See your owner's manual if you are unsure exactly where the cables should go.

[Caddyshk]

Originally Posted by schwank

Hi,
I seem to have let my M's battery die over the winter. I remember it was getting weaker in the fall (I did start it every few weeks over the winter).

Is it safe to Jump it? Id like to see if she'll hold a charge, but Im not opposed to just buying a replacement battery (she's out of warranty as of about a week before parking her for the winter).

Thanks!

I wouldn't bother - mine isn't even dead and I'm replacing it in the spring...

[Finnegan]

Whew! When I read the title I was thinking of jumping as in "I'm going to paint it like the General Lee and have some fun a la them Duke Boys..."

[ANUSTART]

Originally Posted by Finnegan

Whew! When I read the title I was thinking of jumping as in "I'm going to paint it like the General Lee and have some fun a la them Duke Boys..."

I thought the same thing.

I would definitely just replace it so you don't end up stranded later. Sears has a Diehard International battery that is a direct replacement. I have one in mine. Was priced around $145.

[mfanatic325]

Originally Posted by mhughett

Yes, but make sure you use the designated posts that are UNDER THE HOOD and not the battery itself. See your owner's manual if you are unsure exactly where the cables should go.

Why not? It's essentially the same thing
Those terminals under the hood all link to the battery anyhow.

[psygnosis]

Originally Posted by mhughett

Yes, but make sure you use the designated posts that are UNDER THE HOOD and not the battery itself. See your owner's manual if you are unsure exactly where the cables should go.

What about a battery charger?

[mfanatic325]

Originally Posted by psygnosis

What about a battery charger?

I would say this is the absolute safest route, assuming that the battery is still in proper working condition and can hold charge.

[schwank]

Thanks guys

[mhughett]

Originally Posted by mfanatic325

Why not? It's essentially the same thing
Those terminals under the hood all link to the battery anyhow.

The main difference is that it is always a bad idea to hook the negative cables directly to the negative post of the battery being jumped. It is always much better to use another ground. The post under the hood is specifically designed for this. Besides, on the M cars you have to pull off the "shroud" around the battery and the mobility kit and this is kind of a pain.

Also, I use a battery charger all the time during the winter when the car isn't driven for several days. The terminals under the hood make hook-ups much easier.

[Hawkeye]

Oh, I just uncover the battery and let my charger rest in the trunk with it closed (cable makes it out alright to the wall).

I didn't even know we had terminals under the hood, haha. Also, why a bad idea to hook the neg terminal up when jumping? Wasn't it designed to be that way?

[SCHMOUPE]

Originally Posted by mhughett

The main difference is that it is always a bad idea to hook the negative cables directly to the negative post of the battery being jumped. It is always much better to use another ground. The post under the hood is specifically designed for this. Besides, on the M cars you have to pull off the "shroud" around the battery and the mobility kit and this is kind of a pain.

Also, I use a battery charger all the time during the winter when the car isn't driven for several days. The terminals under the hood make hook-ups much easier.

For the record, I had to jump my car once and it was stuck in the garage with the front being blocked off. I used the battery terminals in the back and the car seems to be still OK. Definitely invest in a battery tender for winters and any periods of time that the car is not being driven. 50 dollars worth spending

[mfanatic325]

Yeah, I still don't see how connecting directly to the battery terminals can be bad. It's all the same. The ground post in the engine bay is a common ground with the battery's negative terminal; rendering it the same in the end.
I did half an electrical engineering major, and I'm not seeing a quantifiable reason to not connect directly to the battery...

Plus, not all cars have ease of access like BMW's. And therefore, most cars require you to jump the battery terminals directly. Germans just thought outside the box since a while back =P

[ANUSTART]

Battery Tender is the best investment you can make if you store a vehicle. And Stabil.

[Hawkeye]

Yeah, battery tender sure is a life saver

[schwank]

Ahhhhh if only my garage had electricity

[Nhopkins1394]

The main reason to not connect directly to the negative battery post has to do with the spark. It used to be (still is) very dangerous to spark around the hydrogen gases emitted by the battery. Connecting to the engine block or other negative connection would not eliminate the spark but it would be created away from the battery.
All that said, with today's closed /sealed batteries escaping gases are almost non-existent.
The alternate negative connecting point never had anything to do with electronic surges or such.

[mfanatic325]

See that's what I thought. There really is no pertinent reason to NOT hook up directly to the battery's terminals for a jump. Spark-related issues were resolves decades ago, probably even before EFI was made available to the mass public =P

[Hawkeye]

That does make sense out of the whole idea though. Thanks!

[aerobod]

A few examples of exploding batteries due to terminal spark:

http://www.worksafenb.ca/docs/HA-Battery_e.pdf
http://www.honestjohn.co.uk/news/leg...ery-explosions
http://www.thehulltruth.com/boating-...y-explode.html
http://www.bimmerfest.com/forums/showthread.php?t=15924

[Hawkeye]

Originally Posted by aerobod

A few examples of exploding batteries due to terminal spark:

http://www.worksafenb.ca/docs/HA-Battery_e.pdf
http://www.honestjohn.co.uk/news/leg...ery-explosions
http://www.thehulltruth.com/boating-...y-explode.html
http://www.bimmerfest.com/forums/showthread.php?t=15924

1. Most relevant article you posted, although I think they are being overly cautious since it suggests removing the battery every night and storing it indoors and then putting it back in every morning...

2. We have Z4's, which have AGM batteries. Thus, this particular line in this article pertains to us... "There are now available dry AGM batteries used mainly on stop start vehicles, which are a superb starter batteries, don’t explode and last nearly forever."

3. Not even talking about jumping, talking about driving stuff or starting a vehicle and having the battery explode. Kind of a counter point to this argument more than what you were trying to probably portray.

4. Post is nearly 10 years old, and talking about a "Kraft company vehicle" with no other explination. For what anyone knows it could have been a 15 year old car or a car that had been sitting for years. Pretty unreliable IMO.

I think this is pretty much a null point on our Zeds, although some would rather be safe than sorry I guess.

[jdl1pt]

Originally Posted by Finnegan

Whew! When I read the title I was thinking of jumping as in "I'm going to paint it like the General Lee and have some fun a la them Duke Boys..."

+2 I was waiting for some Pics, lol.

As for jumping the battery, I'm sure you are safe, but a battery tender would be the least stressful for the car.