Re: Battery goes flat if left for a week
Perhaps I should have said 'trial and error' instead of guesswork, what's needed is to test the various elements of the system systematically.
1) Is there a 'significant' drain on the battery with the system at rest?
2) Is there enough current available to the battery when the system is under load - lights on, heater/aircon on, rear demister on,...,...,...
3) Can the battery hold enough charge? Drop-test it (not on your foot!)
Any other approach leaves room for doubt or ambiguity, and the possibility of replacing things , at a cost, which aint faulty.