12V (low-voltage) battery warning
Besides the big drive battery, every Tesla has a small low-voltage battery that runs the locks, computers and lights. Older cars use a 12V lead-acid battery; newer cars use a lithium-ion low-voltage battery.
The warning
A message such as "12V battery needs service" means the low-voltage battery is wearing out. Book a replacement through the Tesla app soon. Mobile Service usually replaces it at your home.
If it goes flat
You may not be able to unlock the car or open the doors from outside.
- Try the key card and phone key.
- If the car is dead, the owner's manual explains how to apply external 12V power to the terminals behind the front tow-eye cover on Model 3 and Model Y, which releases the frunk so you can reach the battery.
- Call Tesla Roadside on 01628 450 660 if you're not comfortable doing this.
Jump-starting another car
Tesla advises against using your Tesla to jump-start another car. Check your owner's manual.
Preventing problems
- Don't leave the main battery near empty for long.
- Respond to the warning promptly.