# Flash Review: Nitecore UM10 and UM20 li-ion chargers



## subwoofer (Dec 30, 2014)

After only recently releasing updates to their multi-chemistry chargers in the form of the D2 and D4 Digi chargers, NITECORE have now released two new li-ion chargers which are designed to integrate into our everyday lives thanks to being powered by the USB chargers we all use to charge our smart-phones.








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Author's Statement for Transparency and Disclosure
The test sample/s featured in this article were provided for technical testing and review by "NITECORE". Test samples are retained by the reviewer following publication of the completed review for the purposes of long term testing and product comparisons.

All output figures and test results published in this review are the sole work of the reviewer, and are carried out independently and without bias. Test results are reported as found, with no embellishments or alteration. Though best endeavours are made to maintain the accuracy of test equipment, the accuracy of these results is not guaranteed and is subject to the test equipment functioning correctly.
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Taking a look around:

Both chargers come in blister style packaging.






Each one comes with a multi-lingual set of instructions.






These chargers are designed to be neat and convenient and here you can see the winder plates on the underneath of the chargers lifted up to reveal the USB output port and supplied cable.






And here with the cable removed. (If you use an Apple product, here you can use your lightning cable and use the supplied cable to connect the UM10 or UM20 to the USB power source)






The base plates, folded back down.






And here is the UM20's main trick, the ability to use a single USB power source to charge both a li-ion cell and a smart-phone.






The UM10 performing the same trick.







Modes and User Interface:

Both the UM10 and UM20 have very simple modes of operation. There is only one switch, and this sliding switch sets the charger's priority of either the li-ion cell or the phone.

The simple backlit display shows the cell state of charge as a percentage, and if the USB output port is active.

Both are powered by plugging a micro-USB cable into the top of the unit from a USB power source.



The UM10 / UM20 in use

Testing of these chargers has been a mixed bag. When trying to incorporate USB ammeters into the circuit (for input to the chargers and output from the chargers), the behaviour became unpredictable, so unfortunately I cannot provide any feedback on actual currents used for the li-ion charging and for the USB output.

It is important to clarify straight away that NITECORE really missed out on a great feature here by NOT making these act like powerbanks. You CANNOT use a charged li-ion cell to power a USB device using the UM10 or UM20. USB output is only enabled when the UM10 or UM20 is itself plugged into a USB power source.

Initially results with both chargers were not reliable, however with further testing (and after quite a bit of plugging and unplugging of both USB connections), things seem to settle. I suspect the connectors were dirty/corroded and after a lot of plugging and unplugging the connections got cleaned up.

One of these initial peculiarities involved the UM20 stopping at 94% and 98% and wouldn't go above this. After powering off the UM20 (unplugging it), and then plugging it back in again, it did finish the charge.

Termination voltages (when showing 100%) seem to vary between 4.16V and 4.20V, so the UM10 and UM20 are not like the D2 and D4 that finish on a rock solid 4.20V

Connecting a smart-phone to the USB output on both chargers does then charge the phone, but there is a 'feature' you need to be aware of.

Once the current draw on the secondary device (smart-phone etc) drops low enough, the UM10/20 starts to turn the USB output on-off-on-off again resulting in that device thinking you are repeatedly plugging in and unplugging the charger. This is not a very healthy state to leave things, as the phone, once fully charged, sits there flashing the screen on and off as the UM10/20 keeps turning on and off its USB output.

If you are there to catch it doing this, no harm will be done, but if you left it for a long period I would be concerned about bump-topping-up the battery and damaging it.

Of course regarding cell charging current, this is essentially limited by your USB charger itself. The UM10 and UM20 will work with anything from a standard computer USB port (typically limited to 500mA) to a dedicated high current USB charger.

NITECORE state that both units are capable of data-pass-though to the smart-phone when using a computer USB port. I've not tested this feature as so far I've not needed this functionality.

A note for iphone users, you can still use these chargers as all you need to do is take your lightning cable, and plug this into the USB socket underneath the UM10/20 and the cable that comes with the UM10/20 between your USB charger and the UM10/20. This assumes you are using a charger which has a USB socket in it rather than a fixed cable type of charger.



Review Summary



Things I likeWhat doesn't work so wellCharge a li-ion cell with your phone chargerTermination voltage ranges between 4.16V-4.20VCharge your phone at the same timeNo Powerbank functionSmall and light – good for travellingUSB output switches on and off repeatedly once the phone is chargedNeat integral cable winderCharge speed limited by USB power sourceSelectable priority of phone/li-ion chargingSimple to useUSB data pass-through
 


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## subwoofer (Dec 30, 2014)

Reserved for updates...

1. Data pass through feature now tested with successful transfer of files to and from Android devices.

2. When using a computer USB port to power the UM10/20, it appears to then keep the USB output on even when the phone has finished charging.
- CORRECTION - If you have no security lock on the device, and you have an explorer window open to the device, the USB output is 'kept alive' so keeping the USB output ON. If you have a security code/pattern to access the device, this will eventually lock, and once the device is fully charged, the USB output again goes on-off-on-off.....

NITECORE have asked me to include the following videos which visually summarise the functions of the UM chargers, so here they are


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## Fumer Tue (Dec 30, 2014)

The cable winder design is really awesome.
"No more tangled messes". hahahaha


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## Timothybil (Dec 30, 2014)

After looking at the packaging I can see how Battery Junction got the idea that these could be used as a power bank. I would guess that almost any other charger that has a USB out has one because it CAN be used as a power bank.


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## realista (Dec 30, 2014)

it would have been perfect if they added these 2 features:
1) nimh support
2) powerbank support. usb output still exists....so why exclude the powerbank option?

if they make a new model with these 2 features added, i buy it. and i think lots of members do actually think the same thing. Design and* microusb input is A GOOD IDEA, but the lack of nimh support and powerbank is a CON*


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## subwoofer (Dec 31, 2014)

Data pass through feature now tested with successful transfer of files to and from Android devices.




realista said:


> it would have been perfect if they added these 2 features:
> 1) nimh support
> 2) powerbank support. usb output still exists....so why exclude the powerbank option?
> 
> if they make a new model with these 2 features added, i buy it. and i think lots of members do actually think the same thing. Design and* microusb input is A GOOD IDEA, but the lack of nimh support and powerbank is a CON*



Agreed, although even without NiMh support (which would be ideal), the addition of the powerbank feature would make this so much better. I would also want the USB output to remain on and steady even once the current draw drops.

As a Travel charger for Li-ion it is very convenient though.


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## subwoofer (Dec 31, 2014)

Latest update:

When using a computer USB port to power the UM10/20, it appears to then keep the USB output on even when the phone has finished charging.


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## subwoofer (Dec 31, 2014)

- CORRECTION to previous post - If you have no security lock on the device, and you have an explorer window open to the device, the USB output is 'kept alive' so keeping the USB output ON. If you have a security code/pattern to access the device, this will eventually lock, and once the device is fully charged, the USB output again goes on-off-on-off.....


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## Bicycleflyer (Jan 2, 2015)

Hey subwoofer,

Have you tried the cable wind feature. On my UM-10 the little things that you are supposed to snap the cable into after winding have too small a hole. I don't use it because I am afraid of pinching the insulation, and maybe some wires on my cable. I think tonight I will drill the holes out some and maybe file the slots a little wider.

Otherwise I like the charger. Like you I think Nitecore missed an opportunity to create a power bank. I really have no use for the pass-through feature. Another thing I think they missed out on was not making this a multi chemistry charger. For travel I still prefer my Xtar Hummingbird. It is small and multi chemistry.


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## subwoofer (Jan 4, 2015)

Bicycleflyer said:


> Hey subwoofer,
> 
> Have you tried the cable wind feature. On my UM-10 the little things that you are supposed to snap the cable into after winding have too small a hole. I don't use it because I am afraid of pinching the insulation, and maybe some wires on my cable. I think tonight I will drill the holes out some and maybe file the slots a little wider.
> 
> Otherwise I like the charger. Like you I think Nitecore missed an opportunity to create a power bank. I really have no use for the pass-through feature. Another thing I think they missed out on was not making this a multi chemistry charger. For travel I still prefer my Xtar Hummingbird. It is small and multi chemistry.



I did try the cable winder clip once, and it did seem a bit tight. When these chargers arrived, the loose ends of the cables were tucked into the side of the winder. This is what I've been doing. Not very secure but no cable damage.


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## subwoofer (Jan 4, 2015)

NITECORE have asked me to include the following videos which visually summarise the functions of the UM chargers. I've added them to post 2.

Post 2


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## DaKar (May 1, 2015)

Hi all,

Thanks Subwoofer for the review, very interesting!

Let me make a couple of questions...

Recently I bought a Nitecore EC11 flashlight that come with a UM10 charger and one IMR 18350 battery.
Today I bought a Nitecore EC21 that will come with a Nitecore battery NL186 18650 2600 mAh. 

Do you think I can charge the NL186 18650 2600 mAh in the UM10 charger?

And which of the following batteries can be charged in the UM10?

Nitecore NL189 18650 3400 mAh
Nitecore NL183 18650 2300 mAh 
Nitecore IMR 18650 2000 mAh
PANASONIC NCR 18650B 3400 mAh

In case the UM10 can't load some of these batteries, which charger you recommend?

As you can see I'm a newbie in the flashlights world 

Thank you very much


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## subwoofer (May 2, 2015)

DaKar said:


> Hi all,
> 
> Thanks Subwoofer for the review, very interesting!
> 
> ...



If you check the NITECORE website:
http://www.nitecore.com/productDetail.aspx?id=130

you will see the UM10 is a Li-ion/IMR and can charge anything from 18650 to 10440, so all the cells you have listed are fine in the UM10. The bigger ones will just take longer to charge.


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## DaKar (May 2, 2015)

Thanks subwoofer for the fast reply :thumbsup:


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## nfetterly (May 2, 2015)

Wow. What a missed opportunity - no power bank. I looked at the photos and started thinking about heading to Amazon to pick one up. 

Not meaning to hijack thread, but...

For me a perfect charger would
1. accept 10440 to 26650 (different charge rates)
2. usb powered (can accept and benefit from 2A charger)
3. power bank
Xtar VP2 very close to perfect - would love 2A out.....


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## IonicBond (May 5, 2015)

subwoofer said:


> Initially results with both chargers were not reliable, however with further testing (and after quite a bit of plugging and unplugging of both USB connections), things seem to settle. I suspect the connectors were dirty/corroded and after a lot of plugging and unplugging the connections got cleaned up.



I could never get my UM10 to charge. I was so bummed because I could see the display come to life with the battery inserted, but the micro-usb port never cleaned up for me despite about 50 insertions / retractions with different cable depths etc. I should have returned it, but tossed it. I hope our experiences with the port are the rare occurrence.


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## BriteGeek (Aug 14, 2015)

Sadly, I am not very happy with my UM10. On some batteries which work quite well, and charge just fine in the D4, I intermittently get an EE error. Tried changing cords, power sources, no go. Problem is worse with the 16340s I have as they wont charge at all. Lastly, when it reaches 4.2 volts it says it is only at 93%. Guess it goes in the semi junk drawer which is a shame as I liked the concept. For now I'll just use my Zero Hour single cell charger in my backpack.

UPDATE: I received my EC11 yesterday, and it came with an IMR18350 designated by Nitecore as a NI18630A. I did not run into the problem I had trying to charge a 16340, but while it did appear to stall at 99%, which when I monitored the battery with my Fluke it showed an alternating voltage of 4.19-4.20VDC, it did finally make it to 100%. Final voltage at 100% measured 4.19VDC on the Fluke. I will be keeping it out of the junk drawer if for no other reason than to keep the EC11's battery charged. BTW: The EC11 is AWSOME!!! (not perfect, but still quite nice!)


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## WarRaven (Aug 14, 2015)

I've the UM20, it is still over the place charging different cells.
Usually just stalls out, showing 93% on display and never getting past or suddenly finishing.
👎 imo


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## WarRaven (Sep 28, 2015)

Update.
Since my last post on this charger I decided to play around with it again.
I lightly sanded contact points in both carriages, and it is now completing a charge on either side.
4.15v on every cell I've ran through it, right on.


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## subwoofer (Sep 29, 2015)

WarRaven said:


> Update.
> Since my last post on this charger I decided to play around with it again.
> I lightly sanded contact points in both carriages, and it is now completing a charge on either side.
> 4.15v on every cell I've ran through it, right on.



Great update, thanks. I had some issues with the micro usb contacts where I had to insert the cable many times to 'clean' the contacts. I wonder if NITECORE had some lacquer, release agent or something else on the contact surfaces causing issues with the reliability of the connection. Your sanding of the contacts will have cleaned them up and seems to support this idea. What you will likely find though is that every now and then you need to sand them again as corrosion may well affect the connection.


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## WarRaven (Sep 29, 2015)

subwoofer said:


> Great update, thanks. I had some issues with the micro usb contacts where I had to insert the cable many times to 'clean' the contacts. I wonder if NITECORE had some lacquer, release agent or something else on the contact surfaces causing issues with the reliability of the connection. Your sanding of the contacts will have cleaned them up and seems to support this idea. What you will likely find though is that every now and then you need to sand them again as corrosion may well affect the connection.


I'm there with you Sub!
Thank you too Sir.

It may have been shipping grease, or like you think a spot where conductivity is seriously reduced.
That part of the USB made me try that a lot first, I felt it was the key, I was just thinking of wrong part in my case. 
So it seems like a shipping grease or corrosion layer.

Works well now, both sides, one was worse then other.


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## sidecross (Sep 29, 2015)

Would the UM20 work well with a 14 watt Sunjack solar panel and would a 10,000 mAh battery bank charge a UM20? Thank you.


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