[GTATX]

Can someone provide correct parts number for 2020 M8 comp battery please. Also does it have to be Lithium or AGM is a possibility as well. Also when changing battery can it be coded via protool on android or no coding needed?

[GTATX]

Only reason I possibly need a battery is due to this code whenever I brake boost or launch. BMW won’t touch the battery as I have a amplifier connected to it even though it’s a JL HD750/1 and they normally don’t draw a lot of power.

[claykin]

That JL amp can draw upwards of 40A. Have you tried disconnecting the amp for a few days to see if the fault code remains or clears?

Btw, I'm pretty sure your M8 has a LiOn 70Ah 12V battery. BMW part 61-21-8-092-860. Confirm this with your parts department. It's an expensive battery, likely over $1200 just for the battery itself.

[Tenac]

I agree with claykin try to isolate the issue.

Also agree its LiOn, but you can put AGM in if you want just have to code it. I have a BMW tool now that allows for this via OBD2 port. Not sure about the phone. Also I did not know this before but BMW allows you to program the exact battery going into the car, so say you are OEM 90amp and you install a 95 or 85 you can actually just program it the car will safely adjust for that... Kinda cool and did not know.

[GTATX]

Thx guys

[Qsilver7]

Connecting things directly to the battery can be the cause of the Check Control warnings.

When you connect directly to the battery, the IBS (intelligent battery sensor) is kept out of the loop…so it has no way of knowing that an unknown draw on the battery is occurring.