How do you keep it plugged in all the time ? Does it need to be plugged into the "mains" like a 3 pin indoors, please ? I thought these could be left in the car under the bonnet alongside and attached to the battery somehow......pardon my ignorance but I'm confused now !!
I just bought a new battery but my car's pretty heavy on electronic "stuff" and my doors are electric too so I'm manic about making it last !