dragonfx

Problem with my '08 528i.
Got a message on my I drive that there is an " Increased battery discharge" And then the car wouldn't start . Thought it may have been caused by the cold weather , but then int started up a few hours later. The next day it started up fine and about mid week, the "Increased battery discharge" message came up again!

This time I was a t a gas station and it looked like the electrical system was rebooting. Luckily it started and the I drive message read," drive longer to keep battery charge"

The next day it wouldn't start again and I tried jumping the battery, no luck, wouldn't even crank. The interior lights, alarm, angel eyes, radio,etc , work. So, I assume its not the battery?? What maybe draining the battery? And, has anyone else had this problem before?

Looking to have it bedded to Mr.M on 34 in Wall ,NJ since its the closest shop to my house . Any input or similar experience?

Thanks

rice_bowl

Had similar problem on my '10 535. The day after I bought it CPO off the lot, it wouldnt turn over and just clicked. The radio etc worked, and the car started up after jumping it. I got increased battery discharge as well and the drive longer to keep battery charged.

Took it back for a replacement battery, apparently it's fairly common.

Campfamily

These cars are tough on batteries. If it's more than about 4 years old, time to get a new one. If you don't drive your car a lot, or if it's going to sit for a while without being driven, consider getting a Battery Tender Plus, available on Amazon for under $50. Also, lock your car when you park it, and make sure the key isn't located close enough to the car that the car can sense it, particularly if you have Comfort Access. The electronic systems on this car remain active if the key is close, which then will drain the battery. This is a pretty common issue with later model 5-series.

Keith

dragonfx

When you put the key in, does a symbol of a car on a lift appear? After changing the battery, have you guys experienced this problem again?

luigi524td

Symptoms all point to a failing battery. There are hundreds of posts about replacement alternatives and the need to "register" an aftermarket or OEM battery. IMHO, I recommend replacement with an original spec AGM battery and have it registered by an indy. If money is no object (or if it's covered by some warranty) have a dealer do the replacement. Be sure to verify alternator output - they sometimes go bad and if not supplying the required output even a new battery will die in time. As you probably know, there is an IBS in the battery circuit. Unfortunately I'm not aware of any test procedure to confirm it is working properly. When I had my battery replaced by my dealer I had them swap out the IBS - there was no additional labor and the thing cost less than $100.

The advice about using a battery tender is a good one. IF you buy a "conventional" battery any brand name tender will work; the AGM batteries require a special tender to adjust for unique charging characteristics. And remember to connect it via the under-hood terminal - NOT at the battery posts!

Good luck dealing with this problematic battery drain situation - I think BMW got it mostly sorted out after a few thousand battery replacements.

Giowizzy

@luigi524td... Just curiosity, I wonder what could be the downside of putting the battery tender in the battery post itself?

luigi524td

Good question ... here are my best answers:

1. That's the way BMW recommends battery tenders be connected,
2. Must properly direct charging to battery taking into consideration IBS sensing, related electronics etc
3. It's easier to access than undoing the trunk compartment panels, etc and
4. When I had mine wired into my e60 I used a length of outdoor landscape wiring and coiled it up the excess under the hood. That permitted me to plug in to my Battery Tender even if parked at a distance and not be restricted to the 3-4 foot length of the tender's wiring. You can buy suitable connectors that match the tender's original wiring harness.

FYI, my garage queen ('98 Z3) battery tender is connected directly to the battery - but it's on-board electronics are far less complicated.

Thanks for asking - get your charge on

pcy

Is there any downside to connecting the battery charger directly to battery terminals? If so, what is it?

luigi524td

Read the preceding post.

Giowizzy

Thanks for the extra knowledge though. Appreciate you sharing.