[OAC_Sparky]

(11-24-2011, 08:20 AM)euro_zx5 Wrote: Cap meters don't give an accurate reading i've been told. Only a proper meter will give you an accurate measurement.

This.

The best way to isolate a possible battery drain is to take a multimeter with an ammeter function; undo your positive battery cable and put the ammeter between the battery and the positive lead.

Make sure the multimeter's internal fuse is rated 5A or better.

If you get a reading of anything more than .5A with the car off, doors shut, and everything off; you have some sort of parasitic power drain.

If you do you will need to start pulling fuses. Pull a fuse, look for a drop. If you get a big drop, the fuse you pulled will tell you what system is causing the drain (ie, cigarette lighter, etc)

The reason your car is more susceptible to parasitic losses in cold weather is because your engine takes more effort to turn over when cold (cold oil), and the current-producing ability and charge rate of any battery is diminished in cold.

Never underestimate the load of a GPS plugged into your socket. The draw more than you think and it doesn't stop drawing when you car is off if it's plugged into your lighter socket. As another has already said, you shouldn't have your cap on an unswitched circuit. It should only be powered when the ignition is on.

Also, any audio amps with a trigger-wire setup, can fail. I had an Alpine head unit many moons ago drawing 7A with the power off; the trigger circuit had failed and the unit was still powering the internal amp even thought the head unit appeared powered off. It would kill the battery overnight; took me a while to find that current leak.