I posted over in gords i4 "poof" thread, but thought it more appropriate here since we're talking about the i4's termination voltage.
Charged up my two protected KeepPower 18650 3100's (charged in separate channels for the 750mA rate). Fresh off the charger I'm measuring 4.27v and 4.28v! I let them sit 20 minutes and still saw 4.27v & 4.28v. Here it is 4 hours and 25 minutes later and I'm still seeing 4.27v & 4.27v. I'm using the same meter I always use and no other charger I have charges this high. My i4 has a molded serial# which matches the box's label. This is my first use of this charger.
So how high is too high? And at what voltage should the over-charge protection kick in?
I don't think it's the meter's battery. I just tried measuring with a cheap junky Harbor Freight DMM known to be measure a few hundredths of a volt lower compared to my good meter (at least by experience measuring the same li-ion cells after charging) and it measured 4.23v on each one. I then pulled a brand new Duracell alkaline from a pack and measured it with both meters: good meter - 1.624v, cheap HF - 1.616v. I don't have another good meter to try and can't pull the battery out of the good meter now (I'm at work).
I would contact who ever you got it from Garrybunk and let them know what its doing once you verify your meters reading.
That could be dangerous with a older cell with high internal resistance.
The higher terminated voltage is also shortening the life of your cells permanently . It would be better if it terminated early.
My i4 seems to charge to about 4.23V / 4.24V, which makes me a little uncomfortable… so I’ve been pulling the batteries before termination. Sometime after the final charge status LED starts blinking, I’ll pull the batteries. I usually catch it somewhere around 4.15V, which I’m much happier with.
It’d be much nicer if I could simply make the charger stop sooner.
Ok, did my little test this morning using 2 protected Tenergy 2600mAh 18650's. Popped cell#1 in the i4, and cell#2 in an ML-102 USB charger. Cell#2 in the ML-102 showed 4.19v on my meter when it finished (well, it bounced between 4.20v and 4.19v). This is what I am used to using the two ML-102's I have. The i4 was still going (third LED flashing), so I pulled the cell (cell#1) and checked voltage - 4.22v. I put it back in and also put cell#2 from the ML-102 in. Cell#2 only showed 2 of the LED's lit on the i4 charge indicator (even minutes later), so I watched closely and pulled the cell as soon it it showed the third LED, checked voltage - 4.21v. I left it out. I did however leave cell#1 in the i4 and monitored it closely. I eventually pulled it off the charger when it reached 4.25v because the i4 still hadn't stopped the charge cycle and I didn't want to go beyond 4.25v.
I now have a warning label on the front of my i4 that it terminates at 4.28v and I will only use it with 4.3v cells (gives me a good excuse to get those now!), although I will also monitor those cells and verify it's still stopping at 4.28v.
Oh well. I'm a bit frustrated, especially since I thought I was buying such a great charger!
Now to try and discharge these over-charged cells a bit. If you don't hear back from me again, well it's been nice being a part of BLF! (JK)
First reported problems with NiMhs getting real hot, now this with charging lithium batteries, looks like a big fail for NiteCore, so much hype a year ago when they released V2 version and everyone was recommending this charger to everybody :D!
I got two, bought them because of supposed reliability and universal use for NiMh and Lithium ion batteries, havent tested them with my lithium batteries(well, have charged two 18650s couple of times, but didnt notice anything wrong with voltages yet), but will definitely do so to see how it treats them.
If it sucks, well, then it will be the worst, overhyped piece of junk evern sold online :D!
The members here who do reviews can only report on the sample they have. Manufacturers can and do change designs and processes, and sometimes their product is the worse for it.
Like I said, at least I can get use out of it with 4.3v cells without needing a Hobby Charger. It's not a total loss. Still dissappointed since I expected that I was stepping up to a quality product. I nevhad really had any intentions of using it for NiMh's.
As you suggested, the 4.200 is the LiIon target voltage, and 1.900 is near the top end of my 20,000 count Fluke 8050A. The others follow the 1-2-5 pattern used by oscilloscopes and other instruments.
I wasn’t making fun of you or your work place, just making it like an audit, like we have to at work.
ISO17025 General requirements for the competence of testing and calibration laboratories, I would guess, the same as the Lab I work in. You see we are in similar jobs.
I received the Pentaref today, and immediately put it to use. My Fluke 8050A, of unknown age and provenance, is within two counts on all five voltages. The specifications on the 8050A are .03% + 2 counts, so it is within specs.
Now I can put an error bar on my i4 voltage: 4.220 V to 4.233 V. That seems a mild overcharge compared with some of the measurements reported in this thread, so I’m going to continue to use the charger without too much worry.
It’s very nice to have the extra confidence in the instrument. Doug was great to deal with, and I’d recommend one of his standards to anyone.
New guy here, but long time flashaholic. Just wanted to chime in that the flashing lights are one of the reasons I added this charger to my collection. Having read about the dangers of cheap lion batteries and chargers, many a late night I have waited and waited wondering just when the red light would turn green so I could finally go to bed. Sure I could take the batteries out and continue the next day, it’s just that when I start something… As for it overcharging, so far all my Trustfire, generic blue wrapper, Sanyo, Samsung and the latest Panasonic 3400’s have come off at 4.19v to 4.20v. Guess I got lucky, and now I have a better idea of how late I have to stay up. :weary: I’m now on the lookout for an Xtar VP1 deal. Yea more lights! :bigsmile:
