Board map
- green box
- 18650 battery on the backside of the baord
- 2x AA
- 1x AAA
- purple box
- serial connector jumper for 2x AA (will to change to 3-way jumper later)
- LED plug-in port (serial connected 1K resistor)
- red boxes and red arrows = active battery selector
- AG3 x1 x2 x3
- AG13 x1 x2 x3
- 18650 battery, 2x AA, 1x AAA
- CR2032, CR1220
- extra plugger, left -, right +
- XH2.54 port
- XH2.00 port
note
- all the series battery should be same brand, same brand new batch
- PRESS slighly hard in case the battery holder didn't hold the batteries well
- all the jumper can be used to insert voltage monitor
- insert only ONE battery group once
test
- AG3 = LR41H, battery drop from 2.9V to 1.6V when run the led