Because of temperature induced chemistry reactions inside the cell. As a general rule heat improves the performance to some extent, chemistry dependent of course. While lots of modern cells do not show increased capacity at larger discharge ratios, increased heat reduction in internal resistance is common.
:-)
That was my thought as well. I have seen li-ions that were cold and run under a 3 amp discharge actual slightly increase in voltage as they were being discharged because the internal heat from being discharged warmed the cell which gives it the ability to provide more current. Since the discharge current is constant the cell doesn’t have to work as hard warm so the voltage goes up slightly. A warm cell will give more capacity in a discharge test than a cold one in my experience.
So do I.
Ordered 2 pieces of 10440 batteries from the aliexpress store. Will check them out 
Thanks again for getting us a new type nice battery Dennis.
Got my 16340 cells from Illumn.
Capacity test using 500 mA discharge current on Lii-500:
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IR, measured using a DMM and resistors:
Cell 1: 0.21 Ohm
Cell 2: 0.20 Ohm
10440 shouldn’t have a button top option? I will see if it will reach the positive contact in my DQG Tiny.
we have button top , we will add it in web,sorry
Thanks for the test, a bit low cap
we test it more than 750mah
Is it possible to add this button top to my current order? It is awaiting shipment at this moment.
yeah， contact Ali Customer service staff to change it
No problem. It may just be the nature of this charger/analyzer (Lii-500). It consistently indicates lower capacity figures on all cells I test with it by about 5-6%.
If I am correct, Vapcell measures capacity with 0.2C, which gives 150mA instead of 500. Maybe, this is the reason of the difference?
The chart they posted (see below) shows them measuring capacity using various current levels, starting with as low as 0.5A and going up to 8A. At 0.5A, their tested capacity is 812mAh. The main difference is their cutoff voltage is 2.5V. Mine is 2.8V, but there can’t be much capacity left there at that point.
I have kept 3V in my charger (default value), but according to the graph that also wouldn’t make much difference.
BTW, I just repeated what they wrote on the Ali site:
Typical Capacity 800mAh (0.2C discharge)
Notice that the “begin volt” is 4.198V. This is almost impossible to achieve even with cells fresh out of the charger, I assume they must have set the termination beyond 4.2V in order to start the test at such high voltage. Probably around 4.25-4.3V.
With the MC3000 you get an option of “d reduce” which is the equivalent of a reversed CV phase for discharging, maybe with a termination current low enough along with the high starting voltage the 800mAh+ capacity can be achieved.
Well, testing chargers discharge down to 2,8V.
If you want full capacity, you need to go down to 2,5V.
Yeah, but I find it hard to believe that 5-6% of the cell’s capacity remains between 2.8 and 2.5V.
When people say down to 2.5/2.8V do they mean under load or not? No one seems to make the distinction but i’m pretty sure it makes a not insignificant difference depending on the rate.
Under load, I believe.
Finally received the two 16340 cells.
Charged then discharged at 1A to give 810mAh and 827mAh.
4.16 resting voltage after one hour.
Performance comparisons:
Vapcell 16340 800mAh vs AWT 16340 550mAh cell.
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Vapcell 14500 1000mAh vs Windyfire 14500 650mAh cell.
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Vapcell 14500 1000mAh vs Windyfire 14500 650mAh cell.
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Vapcell 16340 800mAh vs AWT 16340 550mAh cell.
