I have the WF-188 charger and I have been trying to charge my 18650s protected and non protected. The charger only seems to charge them to about 3.8v and then stops. However when I put it in a cheap china charger than came with my batteries, they continue to charge till they cut out at about 4.2v

Is this a problem with the charger or the batteries? I have the settings on 3.7v and have tried both 300mA and 650mA charging

Those chargers are notorious for not charging to the full 4.2v.

I have 5 of them and they all charge only up to 3.9v-4.1v.

my cheapie chargers charge full as well, like you said.

I actually havent measured my wf-118...

I am going to have to do that soon. I hope it charges to 4.2volts...

Hmmmmm so I just tried charging another battery. It was at ~ 3.8v and it charged it to 4.1v at the same time, it wouldn't let me charge a protected 18650 at 3.7v.....

Part of the problem with those chargers is the rail system. The contacts inside are poor and give false readings which don't let batteries charge when they need to be charged. I pull the charger apart and get rid of the slides. I then solder flexible silicone wire to give positive contact. This solves the problems where it wont charge.

As far as the high charge cutoff point, there is nothing to do about it.

The only reason I use this charger is because it charges everything...even my massive 32600's.

Unhappy 18650

Out of the 10 or 20 of the WF-188 chargers that I have tested, every one of the brand new ones that have the blue box, have all been just fine. (all the ones that I got from lighthound)

And just about every single one of the cheaper (supposedly brand new) ones that I have gotten from other sources (like ebay or other cheap sellers), have been delivered only in the bubble wrap. Not in the box.

And all of those have been crap. Like maybe they were selling returned or faulty chargers or something...

Hmm... interesting thought. You could be right.

I got my WF-188 from ebay (china or H.Kong) unboxed just bubble wrapped. Last night I charged all 5 of my 18650's (mix of Sanyo & Tenergy unprotected) and my results were a range of 3.85v-4.3v with an average of 4.03v. My results seem to mirror rocket689's. Taking it apart and soldering a wire is an interesting idea, I may try that.

Yup, that sounds familiar.... all of mine either came from china via Ebay or DX (unboxed/ wrapped in bubble wrap)

Had problems with almost every one I ever got from DX charging to the right voltage but I only had one with and issue (bad rail would not charge in one of the slots fixed it) from Kaidomain. All the ones I actually tested for voltage and the one I use from Kaidomain came out about +/-.05V from 4.2V depending on the cell. I would bet DX is buying one-off ones from the manufacturer or just plain knockoffs and is why a lot of people are experiencing problems.

I have removed the rails. soldered wires on and will report back new charging results. I couldn't resist trying this little mod

Although my avg has dropped a little to 3.985v, now every batt has charged to a min of 3.95v which is up from 3.85v. Looks like this mod has reduced the range of volts so they are all closer to 4v but not any higher . I still like this charger though

I really need to get my sales thread up for my tested chargers with the rail fixes already applied. :P

Well I did the soldering job and I have seen an improvement!. It is now charging consistently at ~4.2v whereas it would previously be doing ~4.0v. Just waiting for the battery to charge and I see what voltage it charges up to

Edit: ~4.15v

Im glad to hear that the mod helped.