5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
I have a 1995 525i with 68,000 miles in great condition, that I have not owned too long. I drive in only about once a month as I prefer my jeep. However last two times I got in it to go for a drive, the battery was dead (about a month apart). Battery is only a year old so that is not it. I put an ammeter in series with the negative terminal and cable, with engine off, and doors closed, and all internal lights off, and read 32ma steady current. My question: is this normal? Do others 525i batteries go dead also when they don't drive it for a while? Could it be the radio and the internal alarm that is drawing that much current? Your thoughts and experiences would be appreciated. PS: I did a search using "dead battery" but got 7 pages, and after reviewing 3 and not seeing my problem, decided to check directly with members.
Since you use it once a month..you may want to consider disconnecting the battery....make sure u have radio code if your system requires it....some electronic components stay on but I don't think the draw is strong enough to kill battery unless the battery is weak to begin with.....
32mA seems a little high especially on a car of that year. did you make sure to latch the trunk when you did the draw test. although i think of it now the battery is prolly under the rear seat or in the engine compartment? normal should be around 15mA. if all the door latches and things are closed and there is still a draw then you can start pulling fuses untill the draw goes down. do you have any aftermarket electronics on the car i.e. car alarm,radio,radar detector......
or you could do as billB said and just disconnect the battery. or you could get a battery tender.
32mA is actually within spec. The spec is 40mA. BMW sells a portable battery charger for cases in which the vehicle isnt driven often enough to keep the battery charged. i highly recommend it. while 32mA is within spec it is murder on a battery if the battery is not constantly being replenished by daily drives. Check with your local BMW dealer parts dept. for the charger, I think its pretty affordable.
Thank you Bill B. for input--yes, all trunks, doors etc. closed when ammeter reading noted. Car is stock, no after market electronics noted.
Dirty Tool, thank you as well, battery checked ok today, no bad cells, and now fully charged. Attendant said he had same battery and asked what was the problem. I explanined rarely drove car, and battery dead. He explained he had mercades benz, he rarely drove and had same problem. He said he started it once a week for 20 minutes and now one year later, never has had a dead battery.
Definately will start and run it at least once a week. Will advise of results. Thanks again for your inputs, it has helped me come to this decision.
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