[E93_335i_514]

Hello,

I am new to the forum and I need help with a battery drain that is now driving me nuts.

Ma battery dies after 4 days without driving the car. The car goes into sleep after around 30 minutes or so and then the battery drain is 0.28A. Occasionally it would drop to just 0.08A but come back to 0.28/0.30A. I tried removing all the fuses behind the glovebox one by one, with no luck as the current drain never dropped during the process.

Any idea where to look now?

[TheMidnightNarwhal]

Following, having similar issue. Have a drain between 200 - 100mA. Don't remember what exactly it was but I also recall pulling fuses didn't stop it. Fixed my comfort access issue thinking it was handles but still happens. Had a code for FRM sensor, unplugged it still there.

Not sure what else to do if pulling fuses don't do anything.

[gbalthrop]

Originally Posted by E93_335i_514

... My battery dies after 4 days without driving the car. The car goes into sleep after around 30 minutes or so and then the battery drain is 0.28A. Occasionally it would drop to just 0.08A but come back to 0.28/0.30A. I tried removing all the fuses behind the glovebox one by one, with no luck as the current drain never dropped during the process...

Suggestions:
1. Failed Alternator Diode (electrical Check-Valve) can allow current to flow BACK to Alternator from Battery after engine shut-down. That current flow is from the (+) Post of the Battery, through the LARGE Red B+ cable from Post to Transfer Point in front of battery, under vehicle to Jumpstart Terminal, and then from JS Terminal to Alternator.

2. Rear of Alternator will get WARM/HOT from current flow if that is "Parasitic Draw cause.

3. Clamp Meter that can measure "DC Amps/Current" costs $30-$40:
https://www.amazon.com/Electrical-Au...3&sr=8-19&th=1

4. If you have literally pulled every fuse on JB Fuse Panel, without change in current flow, then the Alternator Diodes are likely suspect. Clamp Meter on Large Red B+ wire would be quick proof.

5. ISTA has a "Test Plan" that you can run for a particular Fault Code. Try that for 2DED Fault Code. See attached pdf for procedure.
George

[TheMidnightNarwhal]

Originally Posted by gbalthrop

Suggestions:
1. Failed Alternator Diode (electrical Check-Valve) can allow current to flow BACK to Alternator from Battery after engine shut-down. That current flow is from the (+) Post of the Battery, through the LARGE Red B+ cable from Post to Transfer Point in front of battery, under vehicle to Jumpstart Terminal, and then from JS Terminal to Alternator.

2. Rear of Alternator will get WARM/HOT from current flow if that is "Parasitic Draw cause.

3. Clamp Meter that can measure "DC Amps/Current" costs $30-$40:
https://www.amazon.com/Electrical-Au...3&sr=8-19&th=1

4. If you have literally pulled every fuse on JB Fuse Panel, without change in current flow, then the Alternator Diodes are likely suspect. Clamp Meter on Large Red B+ wire would be quick proof.

5. ISTA has a "Test Plan" that you can run for a particular Fault Code. Try that for 2DED Fault Code. See attached pdf for procedure.
George

Thanks I was putting it off, didn't have a clamp meter and didn't like interrupting circuit with multimeter.Didn't want a no name Amazon, got a nice Klein CL390, I'm sure it will be useful for other applications.

Now I'm testing and sending the sleep command and the draw seems minimal (~ 40mA). Maybe because I'm measuring at the negative cable but from what I understand, it should be the same amount either positive or negative right.

[TheMidnightNarwhal]

Hmm after trying to get more readings, seems like my issue might be intermittent. Could a bad alternator only cause intermittent drains?

[TheMidnightNarwhal]

Okay another update, I've been monitoring it every few hours from time to time and cannot get a amp drain at all... only drain I can catch is like before it goes to sleep, but I doubt a 400mA drain for ~ 30 mins would drain that much right? I confirmed my meter works because if I plug my 7A battery charger, I'll get ~ 7amps reading on my clamp meter on neg cable.

That said, I monitored my voltage as well and fully charged it tops at ~ 12.6v but then it seems that it drains quickly if I just open a door, have a light on or play music or even overnight doing nothing it will drain a bit. I tested it this night and after looking at it now late this morning, my battery is now 12.41 volts.

Could my battery be bad? I did already change it twice and the most recent is June 2023 trying to chase this issue. It's a Cotsco battery so second time was free warranty. I do have a theory, I only fixed my comfort access access issue around March of this year, perhaps my handles were draining the battery and have damaged it to the point where it can't hold full charge and discharges quickly when in use? I've often charged it over the winter because it drained. The only thing that pokes a hole in my theory is that I do have a closed circuit violation code sometimes where it says a drain has occurred for over 6 hours between 200mA - 1000mA. Also using my intelligent battery tester, it tells me my battery is good but to recharge. Maybe I need a load battery tester?

Oh also another data point, my battery charger also seems to never ever be able to fully charge it. I've only caught it sometimes where it will be fully charged and my charger lights stop blinking, but then few moments later, the fourth light will start to blink again and starts to charge again. Idk if maybe BMW voltage readings throw off the charge indicator on the charger.