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BMW 3-Series (E90 E92) Forum
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Faulty Battery?
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03-01-2021, 02:15 AM | #1 |
Private First Class
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Faulty Battery?
Hey Guys,
I replaced my battery in my e93 just before Christmas. This weekend the car was absolutely dead, no power at all I thought it may be the b+ wire fault but this recall had been done. Anyway we figured out it was a dead battery, we replaced it with a fully charged battery from another car and the car was back! I got the battery coded the day it was installed. I have driven the car at least once a week. the voltage on the battery is currently 5AH. I have been advised this battery should now be replaced. Do you think this is a faulty battery? If so i purchased it from a bmw dealer, would i be in my rights to ask for a replacement? |
03-01-2021, 05:32 AM | #2 |
Private First Class
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Are you 100% sure the alternator is putting out correct voltage when running... from memory around the 14v mark (or at least well into the high 13v range)?
Problem may not lie with your battery at all. |
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03-01-2021, 07:36 AM | #4 |
Private
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It could also be the car is not going to sleep after you lock the car, Some thing not going to sleep which would drain the battery.
I think a good battery should read around 12.8V when not running & 14+V when the engine is running |
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03-01-2021, 08:43 AM | #5 |
Captain
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Coley is right, I would be checking if the car is going to sleep and you don't have a parasitic draw. If you have the IBS on the negative terminal then I believe ISTA can actually tell you if there's excess draw from any of the modules under the service functions. If it doesn't have the IBS then you can open the passenger door and use a screwdriver to manually engage the latch so the car thinks it's shut and then use ISTA to send the sleep command so you dont have to wait 30 mins for a complete sleep. Once the car is sleeping you can use a multimeter and probe the fuses in situ as there's metal on the right and left hand sides of the fuse to probe with a multimeter (saves pulling them out one by one) there's a YouTube video explaining this here.
Also be certain that your alternator is okay, I have videos of mine where sometimes the alternator would work and other times it wouldn't (hidden menu option 9) I replaced the brushes on the voltage regulator but it never made a difference so I claimed on the AA parts and garage and got a brand new Lucas one for £35 excess. |
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03-02-2021, 08:51 AM | #6 |
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So when you say driven once a week, how far is the drive? In these temps and off only driven. short distance once a week would not give the car enough time to fully charge either.
If being driven for long enough then as above a temperamental alternator could be an issue (or a drain somewhere). I had the one on the X5 cause no ends of grief and every time the dealer tested it is was fine. I got them to agree to replace it and all sorted after that.
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