Here is the 2A discharge curve for the first cell:
The charger monitor programm unfortunately crashed while discharging the second cell. So there is just a picture of the charger display. I twas discharged with 2A too:
The cells did match pretty good. But I think you have to discharge them down to 2,5V to get better mAh results.
I expected the difference of roughly 500mAh to be the result of not discharging them to 2.8v but to 3v.
But it might be a combination of the charger not charging them to 100% and showing a little to low results in discharging. So take the above discharge with a grain of salt.
I will get a better charger and we'll see. You can't do anything wrong with an iCharger 206B, right?
My set of batteries arrived yesterday. The good part I found was that they were genuine batteries with clear wrap and apperantly a PCB. The Kapton (or similar) tape and a bar under it runs from tail to head. The bad thing about these batteries were that they had stickers all around it. Had to remove the stickers with some penetrating oil to let them in some tightly fit bodies.
Anyway, I charged one with my XTAR WP2 II charger and made a discharge test with my Accucel 6 hobby charger @ 1A, the max current I could set. I must state here that I uses magnets for connection but they were between the clippers so the clipper could touch the battery directly. Therefore, having a small amount of connection resistance added to the circuit I set my Accucel 6 to NiMH discharge mode and down to a voltage of 2.3V.
The cell measured 3034mAh and the final voltage the charger reads were 2.3V. I didn't have a DMM with me but tried a second discharge cycle at 0.1A and the voltage was back at 3V.
My conclusion,
1. They are really above 3000 mAh, built well and has strong metal tabs at the both poles.
2. The circuit didn't seem to have cut at 3V on my sample
3. The circuit didn't seem to have cut at 2.5V either, but with some inline resistance the real voltage on the cell could be higher.
4. I still don't know if the circuit really works.
- I will try some further tests tonight, and this time I'll try to measure the real voltage on the cell.
I'm gonna buy a lot of these cells if protection circuit is good, not as in the first batch of intl-outdoors batteries. Any new 2A-5A tests of these cells?
There may be a problem in connection - I've started testing my unprotected NCR18650A and it's gone immediately below 3.6V at only 1A. I connect the cell to imax B6 with magnets, and when I've tighten the connection the voltage goes up to 3.8V.
Could you post some numeric results before completing the whole bunch of tests?
Thank you, the results are quite baffling, the discharge starts at 3.6V which is quite low for Panasonic cell. Are you shure that connection leads of your tester are thick enough? The protection board may have high internal resistance. What datecode is printed on your batteries? (it's four-character code like 18DA)
N.Shock wrote that protection board has short circuit protection which trips at 5A. I think PCB works, but in not the most efficient way.
By the way, the cells dissapeared from focalprice and reappeared at ~5% higher price :)