Wuben C3 UNDER charging?

Got a Wuben C3 from Amazon which charges to ~3.80V then stops and the charging light goes green. Repeatable with the included battery and known-good flat top, different cables and USB blocks. Amazon sent a replacement but it does the same thing: Charges to 3.80V then stops. Left it plugged in for another hour with the green charging light and it stays at 3.80V.

What gives? Anyone else have this problem? What’s with the poor quality control, @WUBEN ?

According to this thread below. Most are saying it over charges.

Just get you money back and buy another light that meets you specification, recommend by a member of this forum.

Well, the first, early version had units that were over-charging, then the succeeding version was corrected (the ones that are in dealers now).

This was my thread about the “improved” C3: new C3

As to the op’s concern, that’s an entirely new issure considering the replacement unit was still undercharging.

Try to charge it switched on. There is some magic in the charge controller to detect the switch state that seems to be unreliable.

Hey, that worked… sort of! I inserted a flat-top at 3.70V, turned the light on low and plugged it in. An hour-ish later the charging light went green. I pulled the battery and measured 3.97V. Then I put the cell back in, turned the light on low, and plugged it in again. Charging light went red then green 20 minutes later. Cell tested 4.08V.

I’ll carefully test this and termination more when I have time but at least this trick gives more usable voltages. Annoying bug though.

Thanks!

This is just another built in charger horror story.