The charger worked fine for about a week, then it stopped charging and kept clicking. This caused my battery to become severely drained, to the point that I can now shell out a few hundred bucks for a new battery. Dissatisfied. I will try my luck with the Noco brand. UPDATE: The relay clicking and charging failure seems to be due to poor connection quality at the quick connect (where you can disconnect or connect ring terminals or terminals). ). I suspect that if the resistance at the connector is too high, the charger cannot properly detect the battery condition. However, I had no errors, just no charging. I squeezed the socket pins a bit to tighten the connection and it worked fine again. If I decide to keep this charger, I will remove this plug entirely. Ctek should fix this issue as there are other reviews of the same behavior here.