Battery Capacity Tester V2.0

What is it?

In the year 2016, I have written an Instructable on ” Arduino Capacity Tester – V1.0 ” which was a very straightforward and simple device. The earlier version was based on Ohms Law. The battery to be tested is discharged through a fixed resistor, current and time duration is measured by Arduino, and capacity is calculated by multiplying both the readings ( Discharge current and time).

Why did you make it?

I have salvaged so many old lap-top batteries ( 18650 ) to reuse them in my solar projects. It is very difficult to identify the good cells in the battery pack. Earlier in one of my Power Bank Instructable, I told, you how to identify good cells by measuring their voltages, but this method is not at all reliable. So I really wanted a way to measure each cell’s exact capacity instead of their voltages.

What makes it special?

The main features of Capacity Tester V2.0 are :

1. Capable of measuring the capacity of AA / AAA NiMh / NiCd, 18650 Li-ion, Li-Polymer, and Li FePO4 battery. It is suitable for almost any kind of battery rated below 5V.
2. Users can set the discharge current by using pushbuttons.
3. OLED user Interface
4. The device can be used as an Electronic Load

To test the circuit, first I charged a good Samsung 18650 battery using my ISDT C4 Charger. Then connect the battery to the battery terminal. Now set the current to according to your requirement and long pressed the “UP” button. Then you should hear a beep and the test procedure starts. During the test, you will monitor all the parameters on the OLED display. The battery will discharge until its voltage reaches its low-level threshold (3.2V). The test process will be finished by two long beeps.

What you get in the product?

• Fully Assembled PCB
• Pre-Programmed Arduino
• Oled Display 0.96″
• DC Cable (Optional)
• Ground Standoffs
• Quality PCB (IPC Class II or RoHS)