Stop in for a cup of coffee

toolmanmike said
3 hundredths of an amp isn't much. It must be to keep the module alive.

so I'm actually thinking the formula would be .03 x 24 hours in a day. gives me .72 amp hours a day draw. most car batteries are 75 ah, so 54 days IF 100% discharged. So starting and running once a month to keep a charge should work.