Parasitic Drain
Parasitic drain is the current a parked car draws from the battery when everything is switched off.
What is Parasitic Drain?
A small drain is normal for alarms and memory. Control units need time to go to sleep after locking. The allowed value depends on the car, but many modern cars settle at a few dozen milliamps once all control units are asleep. Pulling fuses one at a time helps find the circuit that draws too much.
How it works
Measured with an ammeter in series with the battery after the car sleeps.
Why it matters for your car
Excessive drain flattens the battery overnight. Aftermarket accessories such as dash cameras, trackers or alarms are frequent causes of excessive drain.
Other terms
- AGM Battery
- Booster Seat (Child Booster)
- Cabin Temperature Sensor
- Clutch Release Bearing
- Dipped Beam (Low Beam)
- Dipstick
- Engine Break-in (Running-in)
- Event Data Recorder (EDR)
- Glovebox
- Ignition Switch
- Injector Coding
- Memory Seats
- Parking Pawl
- Rear Cross Traffic Alert
- Regenerative Braking
- Seatbelt Load Limiter
- Side Window
- Silicone Spray
- Tread Depth
- WMI (World Manufacturer Identifier)