This is a charger/Maintainer which can be used as a charger but will take a little more time to charge your battery. - always plugged to electric current during the winter. My car is rarely driven in the winter and I go out once or twice a week and start it and so far it always starts. the Black & Decker is in my truck using the console outlet and then using electrical power to keep it charging my truck battery. Hope this helps you.
NO!! it is a battery tender.. it will only maintain a fully charged battery that is not being used on a regular basis.. like a boat or a motorcycle during the winter