I use this type of charger since 1 year and have only good results with it but I realized today it charges 18650s (as far as I see it from the builtin "voltmeter" of the Nitecore TM11) up to 4.4v. Is that dangerous or very bad?
Maybe I'm wrong, I'll post an update here once I get my new Multimeter that should arrive anytime now....
TM11's meter is very inprecise (IIRC selfbuilt or some other review guy mentioned that in TM11 review). Get a $5 DMM from Harbor Freight before you start to worry.
Ive been playing around with over charging batteries to test battery protection circuits, it seams 4.3 to 4.4 volts the protect kicks in and its normally around 4.35 volt.
So there could be a few things going on here.
1 your DMM is faulty
2 your charger is over charging and or your leaving them in the charger to long or over night, most cheap chargers do over charge or trickle charge once the green lights on.
3 your charge is faulty
4 the battery protection is not work if the cells are protected or the trickle charge is so low in might not work, but you would have to leave the batteries in the charger once the green light is on for day's
I have the same charger, I always charge my batteries while watching tv or something and keep a eye on it once the light turns green I take the batteries off. When I check them they always come off between 4.13v-4.17v I never leave them sitting on the charger for long after the light turns green.