Instead of posting charts with the results I am posting pictures of the cells with the advertised mAh rating in view with the actual measured mAh capacity written nearby. I am doing it this way for 2 reasons. Firstly, I do not know how to use the advanced editor and secondly, I want the image of the results to be burned into the memories of all of us, especially newbies. The problem has been for many of us, myself included, is that when we get our first Li-ion light and cells, there is a good chance that the cells will be of the UltraFire kind. For a novice, it is hard to know that there are much better cells out there. After all, they charge up, you run them down and they charge up again. They work! How well is something that at first is hard to discern.
18650 red UltraFire “3000” mAh
18650 blue UltraFire “2400”
26650 blue UltraFire “6000” ( I paid about $8 for a cell that has only 2323 mAh!)
16340 TrustFire flames “900 mAh”
14500 gray TrustFire “900 mAh” I have given up on trying to run sk68’s on 14500 cells, as they only run for about 10 minutes. Not good for an EDC. I now use Duraloops, 2000 mAh and a little less light-fantastic runtimes.
All of the above cells are of very poor quality and have NO value. Next up is from a laptop battery that I found in a recycle bin, free cells. Although most laptop throwaways will be worn down, most will probably perform better than the cells pictured above. ALMOST any cell is better than those.
These came from a free pack, there were 6 in the pack, I gave 3 to my brother.
New Old Stock laptop battery pack. Here is the BLF link
Cheap authentic battery packs to harvest 18650 cells 6 - 2600 mAh Samsungs for $10
Another NOS laptop deal, 9 Sony cells for $15
This deal was 8 LG 2200 mAh cells for $8
Even these 18500’s from a Toshiba NOS laptop pull tested out at 1600 mAh. 18650 is for size comparison {about all that cell is good for)
In short, all of my other “name” brand cells tested out to close the rated capacity
EDIT: More results
These AA DuraCells are about 7 years old and have gone through many charge - discharge cycles. Mostly charged with a 30 minute fast charger by DuraCell. It used to charge at 4A or better and the cells got so hot that they could hardly be handled. Definitely not the best way to treat them, but I think they survived all of that abuse pretty well! These cells were even charged sometimes with a 15 minute UniRoss fast charger, but even with my abusive attitude towards them, I pretty much stayed away from those chargers.
Panasonic 3400 mAh protected