My experience with using a "Micro USB 5V 1A 18650 Lithium Battery Charger Board With Protection Module" together with the "16 LED Solar Power Motion Sensor Security Lamp Outdoor Waterproof Light"s solar panel is that it's not charging the battery as well as the original built in PCB. Due to the varying voltage (up to 6V) of the solar panel it's not so well suited as a power source for "Micro USB 5V 1A 18650 Lithium Battery Charger Board With Protection Module". I experimented with diodes in serial (2 diodes gave best result) to lower the voltage. However using the original board allowed the battery to charge with a much higher current. I just cut of the motion sensor, and the power switch. It seems to work well. It's even charging a few mA now here when it's raining. My conclusion is that the "Micro USB 5V 1A 18650 Lithium Battery Charger Board With Protection Module" might be used but the original PCB makes a better job charging the battery. Cheers!