Diagnostic Hub: Finding Your Battery's Parasitic Drain

A parasitic drain is an electrical load that remains active after the vehicle is turned off and the modules have entered sleep mode. Common culprits include aftermarket alarms, faulty glovebox lights, or stuck relays.

The Milliamp Threshold

Using a multimeter in series, a modern luxury vehicle should draw less than 50mA (0.05A) after all systems enter deep sleep (usually 20-30 minutes after locking).