Unlike Bangbad with their button tops and such, FastTech takes care; something quite understandable when you see the money you end up paying there what with one thing and another.
Wellp, conversely I can say that, despite a few hiccups, I find it terrific. :-D
If HenrysCat were to obtain a V(C) curve (voltage to capacity) like the usual ones, it'd be of help. Anyway, let's see if we can make some sort of comparison with the V(t) curves from Henrik:
There are some shape differences like, for example, the nearly instant drop under 4.1V at the start for the non 30Q cell.
I’m cooking mine now. Can’t get consistent mΩ readings worth a damn, but then again I never could. The Ope isn’t getting heat-stroke — yet — charging and discharging at 1A each (all 4 bays loaded), so I should get some indication by tomorrow.
Took a look at HKJ's comparator and unsurprisingly couldn't find any match among famous manufacturer cells. Henrik has not tested all the cells which exist, of course, but given the cost and origin the cell must be manufactured by some decent chinese OEM.
Now what matters is, how good that cell actually is? We'll be waiting for the 5A test, if you are using a 4-wire battery holder the cell's internal resistance will be easily inferred with decent precision by comparing the available V(C) curves.
Wellp, it certainly is no high discharge cell (this or your testing setup is terribly flawed). At the 300mA point there's more than 0.3V of difference between the 5A and the 1A curves, it translates in above 75mΩ of internal resistance and this means your setup must not have independent voltage :???: monitoring, and also the cell looks to be of pretty standard 2C discharge rate.
I do not have fancy discharge testing gear. For me, I drop a cell into a known light and use a large gauge current loop and voltage monitor and cook the cell in something that draws like mad. Look for sag and current draw response.
What is the active load? Model number. Also, could you post a pic of the homemade cell holder? 3 amps is a good enough test for me. I would like to be able to rate cells when I get them and they every 6 months to a year later do the same test again. I use a few multi-cell serial and parallel lights and would like to match them at something higher than 1 amp.
Would you mind sharing what tester? I have this discharge tester in my wishlist (some feedback here), may buy it some time. But if I can find some cheap graphic rendering device, the better.
Aaah, then you have a 4-wire battery holder. Well, this confirms your “3000mAh” cell is a battery of pretty standard discharge. The following is what likely it is: