Electrical · Expert tip
Measure parasitic drain with an ammeter
A battery that dies parked has a drain you can find.
The expert tip
- A healthy car draws under ~50 mA with everything off
- Pull fuses one by one to find the draining circuit
- Common culprits: lights, alarms, modules, bad diodes
Source: Battery & electrical experts
Apply tips that match your car and manual. For anything safety-critical or high-voltage, use a qualified mechanic.