The CEN-TECH battery charger (60653) will not charge when connected to a side connect battery (Chevrolet Tahoe). No light-completely dead. It will work on a top connected battery, motorcycle battery. etc. I connected two other battery chargers to the side connected battery and both of them worked. I do not know if I cannot get a good connection or what but this is the second battery charger from Harbor freight (both 60653) that I have tried in the past two days. Will return for a money refund and try another brand of battery charger. User's recommendation: Your charging panel will tell you that.