help, my bimmer is dead

[vgame64]

I have a 525i from 95 and everything that requires battery power wont work. The car won't start at all, no reaction when I turn the key, no symboles, no brake lights, no nothing.

I looked at my interior light and it looks like I left it on could a jump solve this?

[DanH]

Try to jump it see if it works. You may need a new battery if the interior light drained it, unless the light was on a long time and it is very cold weather.

[SRR2]

It's not necessarily a good idea to jump a totally dead battery -- if it's damaged with shorted cells the resulting overcurrent could explode one or more cells. You'd be better off with a 6A charger that you can let on overnight. Take the battery out of the car to charge it in case it has been damaged by sulfation. Put it somewhere safe, away from the house and any living things. If it charges OK overnight you should be good to go. You'll need to reset the clock and code the radio. The engine will run like crap for a while until the ECU readapts.

[SRR2]

Do not jump it. See my other post.

[vgame64]

Yeah its real cold weather

[vgame64]

can anyone post directions on how to remove the battery?

[632 Regal]

its under the back seat and its a pretty straight forward project. you might even be better off to grab a new battery for the 65 bux at autozone or wherever.

[Jay 535i]

its under the back seat and its a pretty straight forward project. you might even be better off to grab a new battery for the 65 bux at autozone or wherever.

That can't hurt. It's about the same price as a battery charger if you don't already have one.

I've been told that once a battery's been run down to zero it's done for good. I don't know how true that is, though. The guy was trying to sell me a battery at the time ;)

[vgame64]

Does the new battery come charged? Thanks

[DanH]

Sure that could happen srr2. I've seen the loss of a cell occur on a newer battery from driving with a failing alternator. I don't know about from a low wattage light bulb though. Just to be safe use a multimeter to test the battery voltage and see how dead it really is. If you charge the battery and it wont go much higher than 10V then there is a bad cell. (6 cells * 2.1V/cell nominal = 12.6V) Get a new one.

Also, when a car battery is severely discharged in cold weather the liquid inside may freeze up.

Usually when i jump a car I'll leave the cables connected for sometime to the dead car before attempting to start it, that way the battery will charge up. You should never connect the neg batt cable to the dead battery, it could create a spark an ignite the hydrogen gas from a sulfating battery, which happens at charging voltages of > 14.4V on a good battery, so > 12V on one with a shorted cell.

Basic Jumping procedure to minimize risk of explosion:
1. Pos cable to dead car batt.
2. pos cable to good car batt.
3. neg cable to dead car large metal part, keep away from rotating parts
4. neg cable to good car batt.
5. wait for a few minutes while good car is running, charging the battery
6. attempt to start dead car.

If the battery is 4 or 5 or more years old you're better off buying a new one than attempting to revive this one that'll die again when you are out on a cold night with nowhere to go. Its cheaper than a towtruck.


It's not necessarily a good idea to jump a totally dead battery -- if it's damaged with shorted cells the resulting overcurrent could explode one or more cells. You'd be better off with a 6A charger that you can let on overnight. Take the battery out of the car to charge it in case it has been damaged by sulfation. Put it somewhere safe, away from the house and any living things. If it charges OK overnight you should be good to go. You'll need to reset the clock and code the radio. The engine will run like crap for a while until the ECU readapts.

[DanH]

It should be charged, but looses it over time, so it depends on how long its been on the shelf.

You surely could jump a new one if its a little low.


Does the new battery come charged? Thanks

[SRR2]

You should NEVER connect a jump to a battery that's sitting at less than 9 or so volts open circuit. Charge it first with something under 10A until the voltage comes up over 12.

Otherwise, I don't strongly disagree with anything you have here, except that when you have a dead battery I don't care HOW you connect the leads, there's a chance of an explosion due to overcurrent. The OP is obviously a noob when it comes to batteries, so I didn't go into the technical details and finer points. I gave him instructions to attempt restoration of his battery that would be safe for him and his car. If it were my car, I wouldn't do it that way, and you probably wouldn't handle yours that way either. But people blow up batteries all the time. I was attempting to keep him from being one of them.

A 2A drain for long enough time can kill an already weak battery. It WILL cause sulfation if it has been on long enough. It can cause flaking of plates that can collect in the bottom of the cell and short out opposing plates thus shorting the cell. If you have good jumper cables and a good donor battery, you can draw huge currents that will, in some percentage of batteries, result in an explosion.

Better safe than sorry, I always say.

[vgame64]

Thanks for the help everybody...I love these forums and the community behind it. I ended up calling AAA to tow me to the Sears auto so they could slow charge or replace the battery...but instead the tow truck operator insisted that we do a very powerful jump for the battery. So at first he used a little yellow box, but he said he used that all day so it might be drained, and indeed it lighted up the lights in the car, but the engine would not start. So then he connected my car to his truck and viola! it worked. So, I drove it for 30 mins and now its working great.

Woot, thanks for the help everyone!

[SharkmanBMW]

you did what you were not supposed to do, but at least it worked out!

[dacoyote]

Thanks for the help everybody...I love these forums and the community behind it. I ended up calling AAA to tow me to the Sears auto so they could slow charge or replace the battery...but instead the tow truck operator insisted that we do a very powerful jump for the battery. So at first he used a little yellow box, but he said he used that all day so it might be drained, and indeed it lighted up the lights in the car, but the engine would not start. So then he connected my car to his truck and viola! it worked. So, I drove it for 30 mins and now its working great.

Woot, thanks for the help everyone!

Wow... glad you know how to listen...

I was get a new battery.... just my 2cents