This is sold to eBay as a car 12V-24V 18650 charging adapter. Internally it is only a 270 ohm resistor and there is NO overcharging protection circuit. The charging current is about 40 mA for 12V and 80mA for 24V. With such currents it needs very long time to charge, It is extremely dangerous to use this circuit as it is as it does not have any protection circuit for overcharging !!! 


     It was modified using an eBay 18650 micro USB charger.