how to check for battery drain with multimeter Page 4

Set your multimeter to amps and move the red lead to the 10A socket, then switch the car off, remove the key, close the doors, and let it go to sleep for 10–30 minutes.

Disconnect the negative battery terminal and place the meter in series: battery negative post → meter → vehicle cable (do not start the car like this unless you fancy buying new fuses).

A healthy parasitic draw is usually around 20–50 mA (some modern cars up to ~80 mA); anything over 0.10 A means something’s throwing an all‑night rave.

Pull fuses one at a time and watch the reading; when it drops, you’ve found the guilty circuit—usual suspects are infotainment, glovebox/boot lights, and aftermarket gizmos.

Latch door strikers or disable courtesy lights so opening a door doesn’t spike the reading and ruin your detective work.

Track the circuit to the offending component (stuck relay, module not sleeping, shorted bulb), repair or replace, and enjoy a battery that isn’t perpetually knackered.