What batteries are you guys using to get these results? If they are newer higher cap batteries it could (Accurately) detect that it could push more voltage into them and do such. I had my i4 give out at 4.17 on my older sanyo 2200’s batteries and about 4.19 on my newer 2600’s.
Then again my meter is junk, but it still is reasonably consistent. I still trust my accucel 6 more than the i4, which on the same cells and meter stops at 4.15v and 4.17v respectively.
I used 4 trustfire lightning from fasttech
they are pretty new, three charging cycles or so.
Calibrated by who, what are their qualifications, and in what Amb conditions and can the calibration be traced back to national physics lab?
Can you tell I like an audit.
No. The differences in termination voltage are either
A) Random variation. The Analog Voltage measurement circuitry has precision error from one cycle to another, especially if the room temperature changes.
or
B) Caused by the time between actual charge termination and your measurement. Once the charge terminates, there will be a little fall-back in voltage. If you wait longer after termination, the fall back will be more.
or
C) Your meter has precision error from one measurement to another
or
D) The Charger follow correct CC/CV Charging protocol, and every battery will take current a little differently once near the end of the CV portion of the charge
or
E) a combination of the above.
They are not, however, due to the charger “Sensing” the higher voltage tolerance of the cell and charging it higher.
PPtk
edit: To add Option D - Brain malfunction and I forgot to type that one out…
my nitecore i2 charges the sanyo 2800 up tu 4,24v when measured right after charging and it drops to 4,23v an hour after…
the panasonic 2900 are terminated at 4,22v…
Despite of your suspicion, it is calibrated monthly every second month by a laboratory only dedicated to do such things. I can’t tell you the name,I don’t know it because the fluke is not exactly mine, it’s part of the tool set my company provides me to do my job. But I borrow it when I need to measure some important thing like this
Cat tell you much about the calibration process, but trust me, in my company they are really obsessed with precision-calibrations-torque settings-deviations, so I think the fluke is properly calibrated.
Edit: for future reference, all my other tools like caliper, feeling gauges or torque wrenches are also calibrated. The lab has ISO certification, is all I know
According to my craftsman DMM, my i4 charges my 3400mah protected Keeppowers in the the 4.22 - 4.23V range.
Both (i4 & i2) definitely slightly overcharge (4.22-23V)
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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?
-Garry
Try replacing the battery in your meter.
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).
-Garry
Wow, that’s too much IMHO 
Overcharge circuit kicks in before 4.32/33V ± 0.03/05V (i.e. ± 1%) if I remember well.
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.
I bought it from WallBuys at 50% off. I'm going to do some more testing tomorrow and it hen perhaps just save it for use with 4.3v cells.
-Garry
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)
-Garry
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.
-Garry
Oh, certainly not… That’s what my BC-700 is for.
However, it was nice that I could give my dad just one charger with his Eneloop SK-68 and Li-Ion Skyray King.
OTOH, it’d be nice if the i4 had a manual voltage switch to support both 3.7V and 3.0V cells.