DIY External Power Pack

That’s the thing I made. I’ll edit this post with more detailed information later.

DIY External Power Pack_cost accounting

MeterialCountin CNYin USD(6.4:1)Comment
Box10.000.00from a box of Hershey's
Wire100.150.02
Glue stick30.900.14
Battery120.003.133.7v/3700mhA
protective circuit for battery13.800.59
Solar pannel16.801.064.5v/78mA
Schottky diode10.500.08ID 5819
booster circuit18.001.25pre-made, output 5V/500mA
LED10.100.02
Resister10.020.002.2k
USB mini port10.280.04
self-lock button10.330.057*7mm
capaciter30.060.011up
Battery Charger IC19.001.41MAX1555
bread board14.000.63
Total price53.948.43