Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

12V battery dying but no warning?

murphyS90D

Member
Jul 2, 2016
663
467
Horsham, PA
I removed my 5 year old 12 volt battery and replaced it with an OHMMU battery.

Tesla-OHMMU-Battery.jpg


This looks a lot better.
 

tga

Supporting Member
Apr 8, 2014
3,931
2,772
New Hampshire
But the contactor cycling remained. Disable remote access in the car, it stops and the car sleeps. Re-enable remote access and the contactors start cycling again. Delete TeslaFi's access token, and the cycling stops and the car sleeps.
I've had TeslaFi disabled for a month now, and the car has been behaving normally. I posted in the support form and got nothing but 5 "me too" responses. I've shut off my renewal PayPal charge and will let it lapse unless they offer some fix.

I didn't want to complicate my original post, but I'm seeing the car occasionally "freak out", disable traction control, ABS, regen, and power brake and steering assist, only to return a few minutes later. I thought I might be chasing a bad ground, ABS wheel speed sensor, etc. At first, my next step was to pull the frunk liner and check/clean the ground studs, but replacing the battery is now an obvious first step.

He was surprised that the battery would die without warning, but confirmed that my other issues (random loss/return of steering/brake assist, regen, traction control and ABS, etc) could be caused by unstable 12V power, possibly causing the gateway to reboot. We'll see what happens.
It turns out these problems are caused by a bad ground - the driver's side frame rail ground stud is corroded and nearly sheared off. The problem is documented here
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top