Nitecore F1 stops charging at 4.08v! Defective?

That seems odd. Nitecore normally makes good chargers… do you have more cells to try with?

Low termination often means old battery or high internal resistance…

4.04V is way lower than HKJ has measured. A reasonable voltage once settled is still above 4.1 (usually above 4.15).

Anyway, the easy way to determine whether this is a defect is to read the voltage immediately when charging finishes. If it isn’t 4.15V or above, I would RMA the unit.

To me that says that the available input current must be greater than or equal to 500ma.

The features posted at Illumn says that it will charge at a rate up to 1A (1,000ma).

I have been looking at picking up this charger due to its size and features. Very useful for backpacking multi day trips. Especially when you consider that you could power it with a folding solar panel.

Here is a review that WoodsWalker did over on CPF:

Nitecore F1 Flexible Charger Review. Field tested! | Candle Power Flashlight Forum

Bob

http://www.illumn.com/batteries-chargers-and-powerpax-carriers/nitecore-f1-flexbank-usb-li-ion-charger-and-powerbank.html

Yes it's supposed to charge at 1.0A if you provide it with enough power. What are you using to measure the battery voltage? Have you tried a different USB wall adapter?

Output: 1000mA MAX (slot), 1000mA MAX (usb)

4.04v is the Soonfire. I’d consider that battery suspect until proven otherwise. The Panasonic was 4.08. HJK indicated in the linked review that things generally settle down to 4.1something. Seems to me the charger is not off much more than 0.05-0.08, again depending on the accuracy of the voltmeter.

The unit costs $10. I personally wouldn’t bother with RMA at that price range unless the seller would simply replace it.


Looks to me like the unit charges the battery at 0.5A. Used as a powerbank it will output up to 1.0A.

INPUT
DC 5V, ≥500mA

OUTPUT
4.2V±1% (slot)/5V±5% (USB), 1000mA MAX (slot)/1000mA (USB)

http://charger.nitecore.com/product/f1

Do your MATH !

Input is 5v @ 500mA
That is 2.5watts to play with … So charge current is very dependent on the state of the battery ……
So the battery voltage determines charge rate ( Remember we have 2.5watts to play with )
So Watts to Amps (A) conversion calculator
Do some math …

Amps = Watts devided by Volts

So we have 2.5 of those watts , divide it by Voltage and you should be left with charge current less any losses inherent in the charger …

( Again don’t forget those nasty variables )

I believe Nitecore says input ≥500mA because the charger can still charge at a reduced rate if you only give it 500mA like some slow ports/chargers.

I’ve charged both the Soonfire and ncr18650a to 4.2v volts in a Nitecore I4 charger. With the F1 I tried the regular 1 amp iPhone power adapter and a 2.4 amp iPad adapter, multiple micro-USB wires, and even tried a few different wall outlets. Nothing helped.

Charger can certainly charge at a lower rate … —-
It can not how ever generate more power out , than goes in ( and on paper that’s 2.5Watt )

Again not taking into consideration lots of nasty variables …

But lets say your battery is at a resting voltage of 3v because you had too …

2.5watt divided by 3 volts = 0.833333333 ………… Amps ( not taking into consideration lots of possible variables )

At 3.5v = 0.715 A
At 4v = 0.625 A
4.1 = 0.61 A

These are not actual figures , but rather paper figures based on Claims by manufacturer ( Maximum ) , and there will be lots of variables that will change these figures in the real world …

I would suggest something like a Charge doctor to monitor the charger , at lest you will know Voltage and Amps going in to the charger … ( Ball park - variable being accuracy / quality of the Charge Doctor )

Those nasty variables !

“≥” means “greater than or equal to”

Anyone else test their F1?
Thanks

I got mine from Banggood. It will only charge up to 4.12 volts on some cells and only up to 3.86(!) volts on others.
I left the cells in the F1 for more than 8 hours. Btw, my cells are all good quality ones

I got my F1 but i havent got my batteries, will do as soon as I get them and update. regs

I’ve gotten anywhere from 4.04v to 4.09v, could possibly be even lower on some of my older cells which I haven’t tested. Would you guys return the product at this point or no? I kind of tore the packaging up lol

It was supposed to charge to 4.2v. Since it doesn’t behave the way it’s described you should be able return it or get a replacement under warranty.

My floor sample stopped at 4.18V which is within the 1% tolerance advertised. And yes it charges at 1A.

4.18v is totally acceptable, I wonder if the rest of us received bunk units.

Yeah… me too. In my haste I threw away all the (external) packaging.
Now BG wants me to register for a replacement with photos of the packaging etc.
Don’t know if I am able to…

I have a UM10 and a UM20. Have tried using the Apple and Samsung wall warts as a power supply and neither worked well. Switched over to an Anker powerport 5 and all problems disappeared. It charges the UM20 with two 18650’s, two tablets and a phone all at the same time fully to 100%. Anker’s car charger works flawlessly too

Apple and Samsung make great phones, but their wall chargers leave something to be desired IMO.

Just got my batteries yesterday and tested immediately for you. Mine stops at 4.18 as well. When I insert it into the Liitokala Li500 it reads 4.18. Less than 10 secs or charging, the voltage changes to 4.20v. I guess that was the termination voltage (4.2) and the rest voltage (4.18) of my Sanyo GA.

Hope that helps. PS: Maybe you should use a powerful USB 5v charger, rated 2A? I used a Huawei tablet 2A charger and got this results.