Introduction: 18650 Lithium Ion Battery Capacity Tester

Hi All,

I had bought few 9800 and few 4200 mAh lithium ion batteries from Aliexpress last year.

They were quite cheap... and as I researched more on them, I found that these are fake and their actual capacity may be very less.

Then I extracted Lithium ion batteries from old laptop battery. But wondered are these still at original capacity or have reduced their capacity

For a beginner DIYer it is difficult to buy expensive testers....

So, in this instructable, I will share how to make 1s lithium ion battery capacity tester

Please share your comments if you like this instructable.

Step 1: What Do We Need ?

- TP4056 with protection
- USB female
- USB doctor
- USB Load
- Battery holder
- Wires
- Wooden board

Lots of batteries from different sources

Step 2: Assembly

- Using hotglue, glue battery holder and TP4056 module
- Connect battery holder to TP4056 on +B and - B
- Connect USB to +Vout and - Vout

Check if everything is connected correctly

Step 3: Test 1 : GTF 9800 MAh

I had got 4 batteries for 6 dollars. It claimed to have 9800mAH

Claimed Capacity : 9800 mAh
Actual capacity : 1000 mAh

Just about 10% of what it claimed

Step 4: Test 2 : 4200 MAh

I had got 4 batteries for 3.5 dollars. It claimed to have 4200mAH

Claimed Capacity : 4200 mAh
Actual capacity : 500 to 600 mAh

Little above 10% of claimed capacity

Step 5: Test 3 : Laptop Batteries LG Make

I extracted these from old HP laptop battery

Claimed Capacity : 3000 mAh
Actual capacity : 2300 mAh

Not bad for 5 year old batteries

Step 6: Test 4 : Laptop Batteries Set Samsung Make

I extracted these from old HP laptop battery

Claimed Capacity : 2200 mAh
Actual capacity : 2000mAh

Not bad for 7 year old batteries

Please share your comments if you like this instructable.


zomtec (author)2017-07-23

The range of the tester is 4V - 20V.

How you test the full battery capacity from 4,2V to 2,5V?

I test the tester and the voltages is very inaccurate under 4V.

The display under 4V becomes darker.

Amit_Jain (author)zomtec2017-07-23

Not for me, it is good tool 2.6v
my usb tester, is not rated for 20v, may be that's why, I am able to test lower voltage

zomtec (author)Amit_Jain2017-07-28

Where you buy it?

My Keweisi tester has a range from 4V - 20V.

All Keweisi tester i found on has a measurement range from DC 4-20V too.

About This Instructable




Bio: I am IT professional, living in Bangalore, India. As new gadgets come out everyday, we indulge in spending significant time and money on these gadgets ... More »
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