sonett - finding battery drain
The battery drained slowely, about 3/10 of a volt per day. As long as I drove it regularly it was no problem but I really needed to find the source of the drain. There are not that many electronic devices in the car so the options were limited.
I hooked up my amp meter between the battery negative terminal and the negative cable. With everything off, there was a 0.14 amp drain. If I turned on the cabin light, it jumped to 0.77 amps just to give you an idea of the scale.
I started pulling fuses until the reading dropped to zero. I turned out that the cigarette lighter fuse was the culprit. There are a number of things connected to this fuse these days. My blue tooth stereo adapter for one, and my voltage and oil pressure guages. The cigarette lighter is normally always hot. I wired up a relay so that the I could use that cigarette lighter circuit for power that was switched by the ignition.
Turns out when I installed my new guages I accidentally tapped into the wrong line. I tapped into the original cigarette ligher power which was always hot rather than tapping into the line off the relay which was only on with the ignition. I switched the lines and the voltage drain dissapeared.