My C-Tek 12V battery charger charges the battery on all my cars (except the Tesla) and now I almost never have a flat battery. Plus it really extends the life of the battery significantly! Batteries seem to last twice as long. I generally try to charge my 12V batteries every 4-6 months. Plug the charger into a wall outlet and using two alligator clamps, the C-Tek charger charges a battery usually overnight.