Charging indicator and protection features Charging indicator: Red light flashes while charging; solid red light when charging is complete Protection functions: Over charge protection, over discharge protection, and over load protection Safe operation: Prevents charging and discharging from happening at the same time Compatibility and connections Battery compatibility: Suitable for Li polymer (polymer) batteries, 18650 lithium cells, and batteries used in cell phones, tablets, and MP3 players Parallel connection capability: The charging board can connect to lithium batteries and can be connected to multiple parallel sections of lithium batteries, as long as the voltages are 3.7 to 5.5 V in parallel (do not connect in series) Usage and practical applications Simple charging management for common devices: Use with Li polymer packs or individual 18650 cells to charge from a suitable 3.7–5.5 V source DIY battery packs in parallel: Create larger capacity packs by wiring multiple lithium cells in parallel for portable power solutions Mobile device battery upkeep: Maintain and recharge batteries used in cell phones, tablets and MP3 players with a safe, protected charging board Notes Do not connect lithium cells in series with this board; parallel connections only are supported within the stated voltage range Ensure the total pack voltage remains within 3.7–5.5 V when connecting in parallel