TEC 06 LI ION 18650 DISCHARGE DATA

[newb123]

I have a TEC 06 Li ion battery capacity checker, I got on ebay.
I set the V cut off at 3.00 V, Discharge current at 1000 mA

These cells were initially charged to about 4.0 V

when testing 4 cells, I got the following data:

1.069 AH capacity 546 mOhms internal resistance
.849 AH capacity .086 mOhms internal Resistance
1.053 AH capacity .081 mOhms Internal Resistance
1.186 AH Capaciy .084 mohms internal resistance

The nominal capacity is 2150 mAH

Does the above TEC 06 data, show these cells as being 1/2 of their original capacity?

 

[obcd]

The capacity in the specification is given at a discharge rate of 0.2CA. That would equal discharging at 430mA instead of 1A
No idea if discharging slower would make a big difference, but worth a test.

Also note that 4.0V is not fully charged. To fully charge you need to go to 4.2V and keep it at that voltage until the charge current drops below a certain value. (See CC/ CV charging).

Another thing that makes a difference is the temperature of the cell. If you do the test in a cold garage, cell capacity will be lower.

Also don't store the cells fully charged for a long period. Discharge to 3.6 - 3.8V before storage.

How old are those cells and where do they come from? You might get a little more capacity out of them, but I doubt you will come close to full capacity.

 

[newb123]

These cells are quite old, from a bike shop who gave them to me. I opened the case, and some were reading 4 V so I kept them, and now doing the discharge test

 

[newb123]

for the .430 mA current discharge, how did you get that # from the .2C discharge rate?

 

[obcd]

1C is typical the nominal capacity for 1 Hour. So, if your cells are 2150mAh and you discharge at 1C, you discharge with 2150mA

They say they measured the capacity at 0.2CA discharge, so I asume that's 2150mA / 5 = 430mA