Three positive battery connections?

AndyW · 06-04-2023, 08:04 PM

So, I am installing a quick disconnect switch in my track car since I have a lightweight battery and realized there are three red wires leaving the BMS (see pic). Does anyone have the decoder ring for which wire goes where? The switch I got is a two pole, one for the alternator connection and one for the battery. Just need to figure out how to correctly hook it up. TIA.

PRTSB1M · 06-05-2023, 09:13 AM

Quote:

Originally Posted by AndyW

So, I am installing a quick disconnect switch in my track car since I have a lightweight battery and realized there are three red wires leaving the BMS (see pic). Does anyone have the decoder ring for which wire goes where? The switch I got is a two pole, one for the alternator connection and one for the battery. Just need to figure out how to correctly hook it up. TIA.

#3 runs to the engine bay positive terminal, which then distributes to the starter/alternator. I'm not certain what #1 and #2 are for.
https://www.realoem.com/bmw/enUS/sho...diagId=12_1339

AndyW · 06-05-2023, 11:08 PM

I ended up just connecting the switch between the positive terminal and the BMS and stuffed the BMS to the left of the battery.

06-04-2023, 08:04 PM	#1
AndyW Supreme Galactic Commander (one galaxy over...) 669 Rep 1,777 Posts Drives: '08 E93, '12 E82, '13 E93 M3 Join Date: Feb 2012 Location: Washington, USA iTrader: (5)	Three positive battery connections? So, I am installing a quick disconnect switch in my track car since I have a lightweight battery and realized there are three red wires leaving the BMS (see pic). Does anyone have the decoder ring for which wire goes where? The switch I got is a two pole, one for the alternator connection and one for the battery. Just need to figure out how to correctly hook it up. TIA. __________________ Best, Andy '12 E82-PS2,Stoptechs,Clubsports+M3 bits,Accusump,Wagner DP+EVO III FMIC,ERCP,BMS Intake,Mason Strut Bar,Wedge Tune
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06-05-2023, 11:08 PM	#3
AndyW Supreme Galactic Commander (one galaxy over...) 669 Rep 1,777 Posts Drives: '08 E93, '12 E82, '13 E93 M3 Join Date: Feb 2012 Location: Washington, USA iTrader: (5)	I ended up just connecting the switch between the positive terminal and the BMS and stuffed the BMS to the left of the battery. __________________ Best, Andy '12 E82-PS2,Stoptechs,Clubsports+M3 bits,Accusump,Wagner DP+EVO III FMIC,ERCP,BMS Intake,Mason Strut Bar,Wedge Tune
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