Brilliant. Probably obvious. But not something I had thought of.

Thanks!

Many of those tenders come with cigarette lighter plugs . . . your BMW might relay disconnect the cigarette lighter after 10-30 minutes (if you even have a cigarette lighter?)

But yeah, they work great, just might need to jury rig it

heck this one makes jury rigging easy

I bought one that mounts directly to the battery. I run it through the trunk, into the back seat, and up onto the back window glass.

I don't know how well it actually works, but the light stays on saying it's doing something, and my battery hasn't died yet. I moved the car about once a month during the winter.

Yes, I followed the suggestion in the other thread and hard-wired my tender onto the Porsche's battery clamp screws. Works great. Haven't had a dead battery since.

EDIT: I don't use a solar one because the car is usually covered. But the plugs and the hardwiring are the same.

Funny you mention that... I also bought a plug-in one along with the battery hardwire connection for the M3 while I was at it just now.

Long ago, I bought the adapter that converts the glove box flashlight charger to a cigarette lighter plug. That one doesn’t shut off when the car is off. I will plug the solar unit in to that.

Oh crap, that's a good idea.

Early production 2003 BMWs (9/2002 production dates) often have a mis-wire* that prevents the glove box flashlight from charging at all. If anyone still has one of those cars, check to make sure the flashlight charges before setting this up, or you'll just have a nice place to store the plug of your charger. :rolleyes:

* This is related to the mis-wire of the aux input connector which prevents the aux input adapter from being detected by the head unit - it is in the same arm of the main wiring harness. Several of the pegboards where the harnesses are laid out had incorrect instruction sheets.