Keeping Battery Charged In A Parking Garage?

[spark146]

Living in NYC I use my E36 convertible infrequently enough that the battery is almost always dead when I go to get it out of the garage. (In fact, I think I'm on my 3rd battery in the past 6 years...). The car often has to sit for a couple of months between uses.

Because it's a public garage I can't use a trickle charger to keep the battery 'up'. Does anyone have suggestions for either (1) ways to reduce draw on the battery when the car is not being used, or (2) any kind of device that will somehow keep the battery charged, remembering that it can't be plugged in anywhere?

Thanks.
spark146

[DEATH2000]

i dunno but couldn't u just disconect the battery?

[Avlany]

What DEATH said. It would be the easiest way to save it man.

[Furious]

tough situation, is it possible to run an extension cord to your spot? the trickle charger can be locked in your trunk. another thing you can do is buy yourself one of those external battery packs that you can hook up and give your self a boost. once the car is running it will start to selfcharge again.