Help!!!!! Battery keeps dying.

Fellas,
I have 91 525i. This is my first BMW. My battery keeps dying but i have had it checked and it's a good battery. Everything shuts down where I cant even get into the car. So I have to leave the hood popped. My interior lights will not come on anymore. Im assuming its my alternator. i have to unhook the negative cable on the battery when its parked. Any suggestions?

Thanks in advance.

If you want to check the alternator many auto parts stores have the ability to do this for you and it's often free of charge. But if you're losing power while the car is not running there is a high probability you have a power drain issue, or simply put something isn't turning off. Start with the easy stuff make sure all your lights are turning off, interior, ruining lamps, trunk light, etc.


ECS Tuning

Thanks for the reply. I forgot to mention that had a bad negative cable to my battery, that I replaced 3 days ago. I thought that was the source, but clearly it wasn't.

I had the same problem with my daughters 1994 525i a month or so ago. Turns out my ignition switch was not terminating correctly, leaving a constant drain on the battery. Apparently, the switch had a bunch of crud built up over the years, so I sprayed it WD40, worked the switch on and off about 10 or so times, repeated the process 3 times. That cleaned the switch out, it now works as advertised.

Hope that helps,

thanks dansr,

This might be a dumb question, but Im a rookie when it comes to working on cars. Im sure you had to take the ignition switch out/off before spraying it with WD40, right?

how new is the battery, and what size is it? i havent a lot of experience with the E34, but one thing i know for sure is they are very sensitive to thier batteries, and a half cut one often wont do, even if it bench tests fine

find a 900-1000 CA Battery. Spend 95-150 On a Euro Spec and change it in every two years for a prorated replacement .These cars go through batteries.

Thanks Luckydog,

I called around and I could not find a battery that's pushing 900-1000. But I did find a 800. Is that acceptable? I dont know how much my curret one is pushing out @ the moment.

Ok, I just found one that has a cold crank at 850 and cranking at 1,050 for $119.00. Is that good

ethrty,

The battery is not very big. In fact, it doesn't fill the space for the battery holder.

If its not wide long heavy and short and come with a small plastic breather vent hose, its proably not a Euro Spec .Min 850 cca..

yes the batteries are huge! they should easily fill the entire space under the seat

Originally Posted by luckydog

find a 900-1000 CA Battery. Spend 95-150 On a Euro Spec and change it in every two years for a prorated replacement .These cars go through batteries.

the e34 in this picture was on cl in washington like a year or so ago haha

Hey Rodney, have you found a good replacement battery? I found that Advance Auto, Walmart and AutoZone carry a battery for our beloved E34s. All around $100 USD.

I did not remove the ignition switch. Just held a paper towel under the steering column and sprayed the heck out of it.

What ever you do, don't try a battery that is not made for the E34, and be sure to connect the vent tube!

i have a 94 325i that i got the other day and was told it had a charging prob,so replaced the the alterantor with a new one and was driving home last night and all the lights dimmed and then the car just died,when i turn the car on all the lights are bright but when i try to start it it just clicks,it fires right up when i jump it and last mabye 5 to 6 miles then dies again,i had the new alterantor tested the day i got it and it was good,all wires are hooked up right,ive checked all my grounds and replaced all the fuses,with a full charge it will last all day,does any one have any ideas what could cause this to happen or has it happened to any one else and they have figured it out,any help would work thank you

Alternator failing under load, thread jacker.

i had the alternator tested and its fine,i was told its my battery,i was also told to check all my ground wires and also check the ignition

Please post this in the e36 forum. They would be more familiar with your car's peculiarities.