Intersting info Rom, but I believe there really is no "accurate" way of calculating how long a battery will last until such time that it is incapable of starting the vehicle, so many variables. Even identical batteries will have different durations. The best way, is to look at the AH rating as just a guide to compare different batteries e.g. a 20 AH battery should last about twice as long as a 10AH. Even a fully charged battery at 12.66V will dip to around
9.6V under starting conditions. But, I agree that a small, light weight battery can not be expected to nomally last for weeks with an appreciable parasitic load. Incidentally, I believe that the total parasitic load on the vehicle, with the immobilizer and alarm set was 20ma, with only the immobilizer it is 15ma, not combined, but I will check that tomorrow. I also believed that included in that 20ma is a small 7ma from the ECU. This total does not include any radio loads.
Michael
Batteries are my friend
