Bmw E34 battery going flat - Bmw Sam

Hi there

Use car every week day(Bmw E34 j reg 518i)works fine, but come the weekend when i am not using it, it goes flat as a doh doh by Monday morning. It has a new battery and its been tested. They say the alternator is fine. Any suggestions what it might be, and has anyone ever experienced this problem before.

Thanx very much

Bmw E34 battery going flat - Alfafan {P}
Probably something left on, not necessarily visible or audible. A couple of weeks ago, SWMBO didn't close the boot properly on Friday, boot light stayed on. Result; flat battery Monday morning.

Bmw E34 battery going flat - Wally Zebon
A common problem on a lot of BMWs is that the rechargeable torch in the glove box drains the battery. Try taking it out and seeing how you get on.

Bmw E34 battery going flat - Bmw Sam
I am sorry if this message repeats itself, but I wrote a lengthy reply, posted and it disappeared !!! So i wanted to say thanx for the replys. Regarding the torch that you mention wally, I looked in the glove compartment and apart from the light bulb - couldn\'t see anything (was dark mind you when i looked, as I didnt get your message until after work.....). May I ask are you certain that the torch etc is in the 518? It mentions it in the 520,525,535i etc in the handbook I have but not the car I have.
What does the rechargable torch look like please? Thank you.
Bmw E34 battery going flat - Dynamic Dave
I wrote a lengthy reply, posted and it disappeared !!!

The server logs you out after 20 mins. For future reference, see here:
Bmw E34 battery going flat - Wally Zebon
If you bought the car second hand, then the chances are that someone could heve removed the torch.
If I\'m not mistaken, all BMWs have them. They sit on the RHS of the glove box. Small rectangular (almost fag packet shaped) - hard to describe without actually looking at one.

You could check out
It\'s an excellent American site dealling with all things BMW.

Bmw E34 battery going flat - Peter D
Gain access to the battery pos terminal and a good meter this is best done with two people. Lock your self in the car ( I assume you battery is under the rear seat is it under the bonnet then override the bonnet switch. Lock the car and set the alarm. let the car settle for 5 mins then carfully place the meter between the battery terninal and the battery clamp now undo the clamp and gentre ease the clamp off the post until the meter gives you a current reading. This is the quiescent or standing current and is normally between 30 and 60 milliamps. Values much greater than this say 500 milli amps is a 6watt bulb on somewhere, probably the boot light. Good Luck Peter
Bmw E34 battery going flat - GGH
I own a BMW 320I auto which has a large 096 size battery fitted in the boot which goes flat within a week unless I use the car. Putting an ampmeter (in all temperatures in case I have door lock heaters etc.)in the battery lead shows a standing current drain of only 25 milliamps. With all the fuses removed the current drops to 18 milliamps, the difference of 7 milliamps being consumed by the radio memory. With this consumption I would expect the battery to last for well over 3 months.
I have removed the battery from the car for up to one month at a time, and it holds it's voltage. I don't use the car much as it is a petrolholic.
As a test I have fitted a brand new 900amp 019 size battery, the largest that will fit into the boot space, and I will let you know the outcome.
P.S. this is one of those car's that has a 5 speed auto without a dipstick or under the bonnet filler!
Bmw E34 battery going flat - John S

How old is the battery? I can only assume that it has deteriorated to the point where its capacity is extremely low, such that 25mA (a perfectly normal 'standing' current) drains it in a week. I'd expect the new battery to solve the problem.

I've never had this problem with my 323. I've left it for about 3 weeks, and it still started instantly. Interested, too, in the petroholic comment - I've never yet got my 323 (manual) under 30 miles/gal, and it has often been well over 35 on a decent run.


John S
Bmw E34 battery going flat - GGH
John S

096 battery is (was)4 years old, I am hopeful that the new 019 battery will be the remedy. However it would be interesting to know why my ampmeter (Avo 8) readings pulse at the rate of 30 times a minute.
I wish my J reg 320I was a 323 manual. Even BMW quote a higher fuel consumption for my 2L engine than any other standard engine in their range, and when you mate it to their dipstickless slush box, you wonder if you will ever see the consumption gauge needle! Rush hour 22mpg over 35 miles, open motorway 35mpg max.
I always felt BMW made this engine and sold it to the public for homologation reasons like my old 970cc Austin Cooper S of which only 1000 where built.

Bmw E34 battery going flat - John S

30 times/minute? Clock?


John S
Bmw E34 battery going flat - GGH
John S

Current pulse as you correctly thought is the clock/computer with 6ma average consumption.If you have any door a little ajar( without any interior light coming on)consumption increases by 150ma !!

Thanks to both John S and Reg the Rover.

Bmw E34 battery going flat - CM
I had an E39 tds (big battery) which had the same problem as yours by the sound of it i.e. OK everyday use but left for 2 days and was flat as a pancake.

Diagnosed the problem as being a short in the radio. The radio worked fine all the time so didn't have a clue it was draining the battery until it happened.
Bmw E34 battery going flat - Bmw Sam
Hi There, thank you for all the replies, most helpful. this is where we are at present. my uncle works for a garage, and he has some experience with BMWs. Yesterday we had a brand new battery fitted, he has checked the Alternator which seems fine. Disconnected a bulb in the glove box, just in case......! checked the boot lights go out. My uncle thinks it maybe a faulty battery, that was causing the problem, which was new. I am leaving it over this weekend to see if it goes flat again !!! If Uncle will be booking it into an Electrical Diagnosis garage,
through them so i wont get ripped off.

Interesting pont about the radio thou' which was changed when i got the car 6 months ago. The radio was changed because we didnt have the code for the origial one, so one was took out of another bmw into my car. It works. If it does go flat again - i will mention about the radio.
Bmw E34 battery going flat - Reg the Rover
We have a 518 like yours and this has occured several times. It was first noticed on an 87 518 that we had from new when it was about 6 months old. Wait for it - the fix was to ensure that the rear nearside passenger door was properly fully shut. When it first happened the local BMW dealer breakdown guy told us that if the door was not shut a short was created somewhere that then gave the effect of a flat battery (i.e. the car would not start) but the battery was fully charged. This has happened twice on our 93 model when a seat belt loop got caught in the door frame so appearing shut but not quite. A mains operated battery booster from Argos will always start the car.
Bmw E34 battery going flat - dansha
hi all

i have the same problem with E39 saloon, i av bought new battery and was running fine for 5 weeks and i had been in car for a long run came back parked the car went out an hour later and was flat. i jump started the car it went but when i went back an hour later it was flat again. the battery is only 5 weeks old can anyone please help? i have removed torch from glove compartment as suggested



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