seriously look into whether it's a timed or peak detection charger. from what you say, with an lcd screen, and everything it should be peak detection, yet you say you can specify a time. My TP610C also has a time function on it but it's a max time to auto stop regardless of what state the batteries are in. It's a safety feature, my batteries get charged till they are full then the charger stops (usually an hour or less) automatically.