Arduino UPS controller
UPS Un-interrupt Power Supply for Arduino from solar charger.
Without solar panel, the solar charger panel can be used as UPS perfectly by from 1 battery 3.7V and ordinary power 6V
------------link to purchase---------------------
1. DFR0559 Sunflower DFROBOT https://ebay.to/2yp8dFS
2. Rechargeable battery 18650 https://ebay.to/2NQ2kGS