Dear Power Integrations, I am designing +13.8V/1A battery charger for emergency light application by using TNY278PN, secondary zener diode feedback, and LowDrop-CC (0.3V) circuit for this battery charger with good efficiency. The control current setpoint is approximately limited at 1.2A. These informations below are our battery specifications: - Seal lead-acid battery 12V/12AH. - Standard Use: 13.5~13.8V that initial current has no limit. - Cycle Use: 14.4~15.0V that initial current is less than 3.6A. I firstly tested with electronic load in CR-mode, the CC circuit is normally operated and cut-off at 1.2A with approximation. My problem is if I directly connected this 13.8V charger with this battery which has the current voltage at 11.5 volts (after discharging), the charger looks auto-restart (Hiccup) mode and can not charge more current into battery. Then I try to disconnect CC circuit from this charger, it also looks auto-restart mode. I guessed that the battery seems draw the output current from charger more than 1.5A during initial charging in first time. Therefore, I try to charge it with higher power battery as such as 13.8V/30W, it can be normally charged. I'm not sure this battery charger specification is suitably selected for this battery or not. Attached pdf file is shown you my battery charger circuit. Please kindly advise me how to solve this problem. Thank you and Best Regards, Terayouth W.