I have two 14.4 volt batteries that were working properly when my previous charger melted. Both batteries are receiving the quick blinking light (defective battery) within 5 minutes of placing in charger. I cannot believe that both batteries are defective just from changing chargers. I am not pleased with this charger as now I'm not sure if the charger damaged the batteries; or the batteries are actaully defective. Without purchasing another battery or charger, I will never know.