There is always a little current draw from the battery with our cars so if you're not going to use a tender, you should pull the battery and store in a cool dry place. If the floor is concrete, put it on a block of wood. I don't let my car sit for more than a month or so without putting the charger on it. I do the same thing with the battery in my boat and golf cart.
Dinan CAI &Throttle body, ESS Tuning TS2, Bimmerbrakes gen3 headers, UUC SSK & DSSR. Achilles oil pump, VAC oil pan baffle
M3 Motor mounts, UUC Trans mounts, Modified clutch style LSD 3.15, TMS front subframe reinforcement, Koni Yellow sports,
H&R sport springs, UUC sway bars, BMW Perf. Rotors, UUC SS brake lines, Hawk HPS pads, CSL replica wheels,
Rotora strut bar, FXR HID conversion, M3 Mirror conversion, BSW stage 1 speakers