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01-11-2026LAST POST
I'll be disconnecting some connections inside of the center console / gear shifter and want to remove power before doing so.
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My 21 X5 40i with mild hybrid and DHP has threes batteries:
1. Engine bay (lithium).
2. Inside trunk (same as yours).
3. Inside the rear fuse cubby, at the bottom (this is probably for active stabilization), can't read the battery label because it is inside a housing.
SmartSaves wroteI don't believe there's any batteries up front. There's lots of hefty wiring connections up there that are running to and from the 12v and HV batteries. EME I believe it's called. Electrical Machine Electronics. The brain of the system connecting the charging port, batteries, and electric motor together. at first I found it odd that there are two 12v batteries for a PHEV. Now I assume the small 12v is necessary since driving in hybrid mode can cause frequent ICE starting.Good to know. Interesting that 45e has two 12V batteries (92 and 50 Ah) at the back. Is there another battery inside the engine bay?
My 21 X5 40i with mild hybrid and DHP has threes batteries:
1. Engine bay (lithium).
2. Inside trunk (same as yours).
3. Inside the rear fuse cubby, at the bottom (this is probably for active stabilization), can't read the battery label because it is inside a housing.
wall_nut wroteThank you for the post. Could you give some instructions on how to open the accessory tray? I have some difficulty opening it. I also have the 45e.Figured it out through trial and error. All you need to do is disconnect the negative lead for the large primary 12v battery and then wait for the car to go to sleep (maybe 5 minutes?). Disconnecting the lead does not immediately defeat power to the car as the high voltage battery powers the vehicle through an inverter. Once the car goes to sleep...it does not wake up or respond to anything. Maybe there's a way to force it off but I didn't want to lock the vehicle as I needed it fully open to work on it.
wbeemer wroteSuper easy, just remove the 6 plastic fasteners, then lift the leading edge and slide to the right to clear the gas strut.Thank you for the post. Could you give some instructions on how to open the accessory tray? I have some difficulty opening it. I also have the 45e.
To remove the fasteners, use a trim removal tool (or flathead screw driver, if you’re into that kind of thing) to lift the center portions, then simply pull with your fingers.
igorlipov wroteNever saw an answer to this. Wanted to confirm that to do work on a 45e, you can disconnect the larger 12v battery negative terminal, wait 5 minutes and then good to go. Any concerns when powering her back up? Going to install a powered sub and want to disconnect 12v power first. Thanks.Is it safe to disconnect both batteries in 45e without computer complications?
wall_nutJust following the thread, I have come across the exact issue mentioned in: https://g05.bimmerpost.com/forums/showthread.php?t=1846114
One of the mentioned solutions is the disconnect the batteries for 5 min for a hard reset.
My question is, can I disconnect the 12v bigger battery without disconnecting the smaller 12v battery (Right Hand side)?
Also, do I need to disconnect the High Voltage Service disconnect before disconnecting the negative terminal from 12v as described in this Rescue Sheet:
https://www.bmw-me.com/content/dam/bmw/marketMIDEAST/bmw-me_com/rescueguidespdf/en/G05PHEV_en-GB.pdf
Thanks in advance.
