- TP4056 Li-ion cell charger module
- Li-ion cell capacity tester module
- 18650 cell holder – 2pcs
- Solder an 18650 cell holder to the charger module.
- Charge 18650 cell till the charger module shows green light (4.2V) – ~2 hours.
- Screw an 18650 cell holder to the tester module
- Screw two 7 ohm 5W resistors in parallel to the load input terminals.
- Set 3.0V as the cutoff voltage on the tester module.
- Press start and wait ~2 hours till the testing is complete.
- Note capacity (Ah) when the testing is complete.
Load resistors get extremely hot while charging.
A recycled 18650 cell from a 5 year old laptop battery showed 1.791 Ah.