It looks like the one from Banggood will require a plug adapter for use in the USA.
I wonder what style of power supply will be included in this group buy?
This post is from Henry Xu, the chief engineer of the BT-C3100: Reply concerning HKJ’s conclusion
(copy/pasted for his post #145Review: Opus BT-C3100 ("dreamcharger!")
Post # 145
1. The charger is oscillating and stops the charging a bit too premature This has been solved by firmware update: charger will make no current increase back in the CV stage. So no oscillating at all circumstances.
2.The “resting”/overheating periods during 2A charging or 4 × 1A discharge
2A charging is supposed to be used for high capacity Li-ion batteries, we should mention this in user manual that charging with ni-mh AA batteries with 2A charging current is not appropriate. Since 1A discharge current for 4 pcs li-ion batteries will generate a lot heat, and the fan exhausting speed is not fast enough.So it can lead to thermo-protection kicked in, which this safety mechanism is designed for. So I hope it is acceptable. If only two batteries is discharged at 1A speed, it should be no problem.
3. Power spikes from the power supply
We noticed for 9A peak current with very little period time of less than 10ms. we improved this problem by adding a larger enough filtering capacitor and its peak current now is reduced to 7A. The problem is not 100% solved, however it is improving the power supply quality significantly.
4. Uses trickle charging for NiMH when cell is fully charged
I think trickle charging current for nimh is necessary. And we believe this is a good feature of this charger. We have no plan to take this trickle charging away for nimh batteries. For li-ion batteries, there is no trickle charge current.