I was thinking of making a 18650 battery tester. Until I made a li-ion battery tester, the variety of affordable devices had increased a lot. Especially the 18650 lithium battery testers with LCD screens are affordable.
I thought I would test 2 batteries, but since I didn’t examine carefully, I understood the situation when I used the module. The first battery slot is for operating the device with an adapter without an external power source. The battery to be tested is placed in the other.
The use of the Battery measuring device is simple, starting from the left, the first USB socket is used as a power source (+ it also charges the battery inserted into the battery socket used as a power source), the first button is on-off (long press) and the mode selection button.
The button in the middle is for changing options. The last button is for start-stop. The USB socket on the right is for testing the battery of devices such as power banks.
18650 Battery Charging and Discharging
AUTO (automatic mode): The battery is charged and then discharged with 1 ampere. (You can repeat this process 9 times from the LOOP section)
DSG (discharge mode): Discharges the battery with 1 ampere
CHG (Charge Mode): Capacity and energy are not measured during charging.
A lot of information about the battery and settings is displayed on the LCD Screen.
- Real-time voltage
- Real-time current
- Real-time power
- Total capacity
- Total energy
- Total working time -hhh: mm: ss
- Internal resistance of the battery
- Working mode menu
- Stop voltage menu
- Cycle times menu
- Status indicator
In the test device, TP4056 (PW4056HH) integrated circuits were used for Lithium 18650 Battery charging. Load resistors are controlled with 8205A mosfets. The device is a price-performance product, but the load resistors (2x 8-ohm 10w) get very hot.
TP4056, Mosfets, Load resistors are passive for cooling, PCB cooling is done. I think it is not enough. OK, the resistors only get hot during discharge, but the heat is very high, critical for LCD screens and mosfets.. We use it for discharge rather than charge anyway.
I also added a cooler to extend the life of the device. It turned out great. Old Notebook Batteries, rechargeable drill batteries, etc. There are many batteries to sort and test capacity…
