This low-voltage battery runs the lights, infotainment, control modules, and cabin accessories. In electric and hybrid vehicles, it handles all the standard 12-volt loads so the high-voltage traction battery is reserved strictly for propulsion. In heavy trucks or modified off-road rigs, it isolates auxiliary gear like winches and fridges to prevent draining the main starter battery.
The hybrid won't boot up because the 12-volt accessory battery in the trunk is completely dead.
In many EVs, if the 12-volt accessory battery dies, the car is completely bricked and cannot even engage the high-voltage system to charge it.
Also heard as
- 12V battery
- auxiliary battery
Related terms
Car battery
A rechargeable 12-volt energy storage unit used to start the engine and power electronics.
EV
An electric vehicle uses one or more electric motors for propulsion instead of an internal combustion engine.
PHEV
A plug-in hybrid electric vehicle combines a combustion engine with a grid-chargeable battery pack.