Nitecore D4 strangeness...

[SpidaFly]

Recently bought a Nitecore D4 (verified authentic) to supplement my tried and true Xtar VP2.

As with any new equipment, I want to test it. I bought 6 brand new Sony VTC6. (Purchased in person from Kidney Puncher, so I'm assuming they are legit.) My intent is to use these in "married" trios in my Fuchai Duo-3.

While testing the batteries as they came off the D4 though, I came across some troubling results:

First: waited overnight for the batteries to reach 4.2V/ALL reading on the D4 like so:

Took the batteries off the charger and immediately tested them:

Hmm. That's not good, right?

Then, into my Fuchai Duo-3:

Wow, it just keeps getting weirder! Now of course I'm more trusting of my GE multimeter than I am of the Fuchai Duo-3's chip. And of course they're close enough in state that it is probably just fine. I have the "married" trios marked so that they'll always be used together in trio config. When I need to drop the 3 battery door for a 2, I just use my slightly older LG HG2s.

So... the questions:
1. My Xtar VP2 always charges all the way to 4.2v. It has been doing so for years, and my multimeter verifies this. I bought the 4-bay Nitecore D4 so that I could charge 6 batteries at a time... but if the battery states aren't close enough in state, I'm not sure I trust it? I really shouldn't be using trios of batteries charged on 2 different devices if I'm getting different battery state readings on the multimeter, right?

2. Are there any known issues with the D4 undercharging? Googling didn't find me very much information... but admittedly my Google-fu is rather weak.

3. Is there some way to calibrate the D4? I sent an email to Nitecore's customer service, but the response I got was BEYOND useless. They basically said to deal with the seller... well I bought it from Nitecore's store on Amazon... so that's not much help...

4. Or should I just return the D4 and invest in a Xtar VP4? Even in that case, are the new VP4s as reliable as, say, my old VP2? (Also I have to admit, the versatility of the D4 REALLY appeals to me since I use other types and sizes of batteries for my GPS, flashlights, etc.)

Your thoughts? Thanks!

 

[Heartsdelight]

I had the exact same charger, it has since died. But before it’s death, I noticed the same thing. I didn’t have a battery meter but I know it undercharged as you have. I think it’s the way Nitecore’s are. I replaced with Nitecore’s 8 bay charger & it’s the same way. How do I know? I have also have a Hohmtech Charger that I got mainly for its Battery Doctor feature. When I transfer a freshly charged battery from the Nitecore to the Hohmtech, it reads like 99%.

 

[stols001]

I've heard good things about the Xtar chargers (I have a nitecore 2 bay) but when I buy another it will probably be an Xtar....

Anna

 

[Wraith504]

i never really care that much about a couple of hundredths.

 

[Skreech]

It might be a safety feature built into the charger to prevent over charging. Normally any charger will charge a l-ion cell to 4.2 volts in constant current mode (except LiFe batteries). It will then switch over to constant voltage mode and hold 4.2 volts whilst finishing off the charge. The charge current will reduce through out the CV stage but the voltage will remain constant at 4.2 volt. When the charge current is down to about 10% of the original current setting in CC mode then the charger will have completed the charge cycle. As soon as you take the battery off the charger you will get a slight voltage sag which is what you are seeing.

In order to have a finished rest voltage of 4.2 volt the battery would need to have been charged higher than 4.2 volts in CV mode. I think they can safely go up to 4.23 volts without damaging the cell but don't quote me on this.

I only know about this stuff because I use an ICharger to charge LiPo batteries for radio control helicopters.

I think what you are seeing is perfectly normal. As long as the cell voltages are the same for a three pack then I personally wouldn't worry about it.

 

[Wraith504]

4.15 is the same as 4.2 if you round up. lol i see so many people comparing charger full readings then measuring with a dmm and the reading is lower than 4.2 by 2 or 3 hundredths and they freak out. I agree with skreech that its likely a safety precaution to prevent overcharge. I dont engineer chargers so dont quote me.

 

[Mr. Relentless]

I like sigelei but the battery readers in them are a little off. If your third battery shows lower then the rest you can rearrange them and the third battery will still show low even though it's a different battery in its place. I have a kaos and one cell says 4.20 and the other says 4.17. I switch the batteries around and nothing on the readout changes at all.