Re: FENIX AND OPUS:UNIFICATION, DEDICATION AND EDIFICATION!!!
HKJ's cell is not the same cell that Capolini tested (of which we don't know how different your cells and the one tested by HKJ had lived its life, etc.) I remember my brand-new Panasonic NCR18650B bowed-out at 3350mah when tested in my BT-C3100. [...]
Of course they are not the exact same cell, but they are both the same model (NCR18650B). The OP's cells were old (177 cycles), and presumably HKJ's were almost new. But HKJ's new cells tested at 3162mAh at 1A, about 6% less than the OP's old cells = 3340mAh at 1A on the Opus BT-C3100.
How else do you propose to explain that 6% difference (probably much higher given the huge age difference) other than inaccuracy of the Opus? We know HKJ is using equipment
much more accurate and precise than the Opus, so the error is surely with the Opus, not HKJ's equipment. Iirc, Opus engineer Henry Xu claimed that they are not using high precision components or very accurate calibration, so 5-10% worst-case error for the Opus should not be too surprising. Note also the charge process can also play a role in the discharge results (e.g. the Opus could be overcharging them, so the OP's cells could be starting with higher capacity then HKJ's cells).
In any case, all factors considered, you shouldn't expect much better for any budget analyzing charger. If you want greater accuracy/precision you'll need to pay more, e.g. the SkyRC MC3000. But most users do not need such, esp. if they are only using the analyzing feature to track the health of cells, since then all that matters is the
relative difference in capacity, not the
absolute values. And the relative differences should be more accurate (at least if you always use the same slot to avoid slot inconsistencies).
