This charger works very well, but very slowly. I charged two car batteries that already started my cars so it was just a maintenance. I did NOT charge a dead battery and it took 16-24 hours to fully charge each battery. If you can afford to spend that much time maintaining your car battery, then this item is worth the cheap price. Otherwise buy something 5-12 amps if you want it done in 3-4 hours. This device is a 1 amp charger only and takes a LONG time to fully charge the battery.