Why don't you put a monitor on it? Cetec or redarc

I have a battery charger with a cigarette lighter end on the cord, and i plug this into the cigarette lighter in the car via an slightly open drivers door window. The charger is connected to the mains via a timer that I have turn on for 30 minutes each day. I just unplug ti when I want to use the car, and the battery is always fully charged.

I really like this idea and know someone else who does this with their mini, but I don't have a power source where the car is stored. I've thought about solar but that could get messy and over complicated.

I have a similar problem, the Pioneer Radio/CD head unit eventually drains the 640CCA battery.

It sounds to me like you're going about the wrong way to solve the problem. Yes, you can keep the battery charged, but an immobilizer shouldn't discharge the battery so quickly. My old one would last about two weeks before the battery started showing signs of a struggle - but it turned out to be the alternator anyway. I've since changed alternators (to one of ConvertableMini's upgraded ones) and changed to anew alarm and immobilizer. I went on holiday for almost 6 weeks with the alarm/immobilizer activated, and it still started up fine.

What I would suggest is seeing how much current is draining from the battery with an accurate multimeter. Then unplug the alternator and check the difference. If it is the immobiliser that's draining, get a new one. If you're happy to do the install yourself, they're very cheap.



Any head unit should have a permanent +12V connection and an accessories connection. The accessories connection effectively acts as a relay - if there's no accessories connection, your head unit should only drain the smallest amount of power (only to keep time and radio presets etc - a AA battery would have enough power to do this). No head unit should drain a battery unless it's old/cheap and given a long amount of time (several weeks).