What battery power supply circuit boards are you using to power your Arduinos?
I need a circuit which is for 2x18650 Li-ion battery.
It needs to have On/OFF switch
place to solder the battery wires
place to solder wires to arduino (this is difficult to find)
USB mini or socket (2.5, 3.5, 5.5mm) for charging
LED which shows whe the batteries are full/charging
protection circuit
USB power output (optional, as then it can load my mobile in the same time)
I have found a type for 4x, but I want to make it lighter.
And I rather have them from China as then the prices is around 6USD.