Just received a BT-C3100 v2.2 which I ordered after reading a handful reviews. Some reviews indicated slight over-charging of 4.2V cells, to 4.22-4.25, which should be within specs. My unit, however, under-charges, it stops at 4.14 - 4.16 V. The displayed voltage at this time is +0.02 V, 4.16 - 4.18. So the charger measures voltage lower than 4.2, and it still terminates for some reason. Measured on the battery terminals with Holdpeak HP-890CN DMM, and I’ve tested that DMM to be accurate against Brymen 869s.
Tested at 1 A charging current with new unprotected Sanyo 2600 mA*h and new unprotected Samsung 30Q. Barely 2 full cycles on Samsung and maybe 7 cycles on Sanyos.
I guess I have two questions:
- Is it a common/known problem?
- Can I somehow calibrate the charger? Say, by resoldering some resistor that affects the voltage reading of the charger?