This Advanced Battery Charging System can help you extend the life of your battery. Simply plug the 4-amp charger into a standard 115-VAC wall outlet and connect the alligator clips to your terminals under the hood. The device's on-board microchip monitors and regulate the charge- virtually eliminating sulfation.
This product is now switchable between AGM (Lead Acid/Standard) batteries and Lithium-Ion batteries (as found in the F80 M3 and F82/F83 M4).