Some tests of Li-ion cells with the Opus BT-C3100 V2.0

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 :slight_smile: 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

Thanks for the great ‘public service’, the true BLF spirit I should say.

Good question, I forgot to mention that all charging and discharging was at 1A, except for the 14500’s. They were charged and discharged at 500mA.
Some of the CrapFire cells have only been lightly used, most have not been used. I soon found out that even wornout laptop pulls are better.
The very first 18650 I ever bought was an UltraFire “4000” mAh. I remember, at the time, I thought I was getting a really good cell. I bought 2 for $10. It turned out those 2 cells were only “half bad”

Bah - nothing to brag. My blue UF would still be undisputed champion - 2mAh @ 1A. :slight_smile:

I wish there was a way to prove the written numbers are legit. I absolutely believe them, but if I link this to someone who is all “ultrafire cells are inexpensive and have the best capacity!” they’d probably reply “So some guy wrote some numbers on a bunch of cells.” :frowning:

The numbers are legit. I did the same thing dchomak did, but with a hobby charger. I did not have so many types of cells, only 3 types, and I did not think to take photos, but the numbers are in the same range. Buying xxxfire cells is flushing money down the toilet.

Great tests, and very nicely presented (please stay away from the advanced editor a little longer :-) )

Those puppies Rock and Roll on a direct drive flashlight, very low impedence.
I have about 10 of those and they are one of my go to batteries for quick/sheer output to test heat sinking.
The red/pink sanyo laptop pulls are barn burners as well.


Awesome, and very easy to see Chi-mAh in action

Easy to quickly see the decent from the crap too good job!!

My blue Ultrafire has 590 mAh

My red one like the first post indicates 3800mA. It came in a cheapo powerbank so has only seen limited draw, maybe 30 cycles. When new and first tested at 0.5A draw with an Accucell-6 (hobby charger) it was ~1000mA. It’s also noticeably light….nothing in there most likely. :bigsmile:

I just got an Opus. It now shows 600mA @ 0.5A draw, and 275 resistance after about a year of use. I’ve got some really really really old li-on that do better than that, and they kind of went through my learning phase and some abuse.

I recently pulled apart a laptop pack from a neighbor’s daughter. The laptop was in abysmal shape and would not hold a charge for 10”. 2 cells were dead…dead. The rest are almost 3x the UF now with lower resistance. I’m sure those cells went through hell.