# Nitecore F1 Flexible Charger Review. Field tested!



## Woods Walker (Jun 13, 2016)

Here is my review of the Nitecore F1 Flexbank Charger. A very flexible charger for outdoors use. There is a little background story to this review. Some time ago I purchased another USB powered lithium ion charger from Nitecore, the UM10. It's a fine little charger though does lack of few options I wanted for outdoors and preparedness applications. First it couldn't act as a power bank aka use the charged battery to charge something else. I knew this when buying the UM10 so wasn't disappointed but still wished for the option. Secondly though it could charge via solar it wasn't fully solar compatible. If there was a solid interruption in power the UM10 like many other chargers would trigger an error requiring it to be plugged back in. Given the potential for clouds etc this meant the UM10 would need to be watched like a hawk when charging via solar. That said Nitecore never claimed it was solar compatible so again not disappointed rather wished for the ability. I still use the UM10 for home charging lithium ion batteries and recommend it.


Moving along some weeks ago Nitecore contacted me for an opportunity to review a new single battery charger geared towards my life style which is very mobile and in the woods. One of my long time wishes is to have control over power in the back country. This new charger appeared to offer me a solution so jumped at the chance to review it. In keeping with the mobile outdoors theme of this gear item most of this review will be done using solar power from my pack away from people and plugs. 


So lets go!


Heading up the mountain. We have sun so there should be plenty of power!







A wild strawberry. It was rather good. Remember don't eat anything in the wild unless you know the identification however this one is kinda obvious. Still be careful out there.







Mountain laurels are in full bloom.

















Solar power! The F1 charger never triggered a charging error during my testing despite my attempts to induce that. The F1 appears solar compatible!












Now that we are setup here is some information about the F1 Flexible charger from the Nitecore site.


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




> The F1 Flex is Nitecore's first outdoor battery charger. Lightweight and durable, this charger is a fantastic way to always have power at your fingertips - no matter how far you travel. Ideal for backpacking, this is the perfect charger for the rugged nature-lovers out there.
> 
> 
> Features:
> ...




So how do the stats stack up under field use and evaluation? First let's take a look at the F1.


It comes with the charger and 2 wide rubber bands to secure the battery. As only one is needed guessing the extra is a backup. I use the yellow band to increase visibility.







Size comparison to a Nitecore NL189 18650.







Compared to a Nitecore UM10 Lithium ion charger. 







Both compared to a 1XCR123 Armytek C1 Pro.







Information from the device is transmitted via 3 green LED light lights.







The first thing the F1 shows is the voltage of the Lithium Ion battery. Nitecore states:




> 1. When a battery is installed inside F1’s charging slot, its power indicators will blink to indicate the battery’s
> voltages. For example, when a 4.2V battery is installed, the top indicator blinks four times, followed by
> two blinks from the indicator in the middle.
> 
> ...


 
I found the following:


1 indicator light and 3.5 volts (first 3 then second 5 blinks) = 30%
3 indicator lights and 4.2 volts (first 4 then second 2 blinks) = 100%
1 indicator light and 3.4 volts (first 3 then second 4 blinks) = 17%
3 indicator lights and 4 volts (first 4 blinks)= 95%


Seemed accurate enough for field use IMHO.




> Sleep Mode
> 
> 
> If neither an external power source nor an external device is connected, F1 will enter sleep mode in 10
> ...




That appear to be the case. 




> 1. During charging, the power indicators will indicate the power levels of the battery in the slot with blinks.
> When power levels are below 3.3V, the three indicators will blink to alarm the user. When power levels
> are below 2.8V, F1 terminates charging to protect the battery.
> 2. When F1 detects a small capacity battery (e.g. 16340, RCR123, 14500, 10440) in its slot, the three
> indicators will blink to alarm the user and F1 terminates charging after five seconds to protect the battery.




I have seen flashing for low battery warning and had the F1 terminate charging. I forgot if the warning is one or 3 lights but doesn't matter as got my warning and it gets cranky around 3.3 volts. As for number 2 that's a bit in the air. It would always flash the 3 LED lights as a warning when a smaller capacity lithium ion is inserted but not always terminate the charging. Sometimes it does terminate the charge, other times it appears to trickle charge at such a slow rate as to make using 16340 and 14500 Lithium ion batteries as power banks impractical. 







So yes it won't use them for the power bank function as stated but not always in the exact way as stated based on my field use. The F1 had no issues charging any of the Lithium ion batteries tested including 16340 and 14500. Was able to use 2600 and 3400 mAh 18650 and 2500 mAh 16650 as a power banks in addition to charging them.




> ·Battery reversed polarity protection and short circuit prevention




Yes. I tested the goober insurance and it works. I can't be trusted with out polarity protection aka putting the battery in [email protected]@ backwards so glad it has that protection.




> 2. F1 features intelligent USB charging management system. Under sufficient input power, F1 can
> simultaneously charge a battery in the slot and a connected external device (with 1000mA current). With
> lower input power, F1 can charge the battery with 500mA current, and charge the external device with
> 1000mA current.
> ...




Yes that appears to be the case based on my solar testing. Pass through charging actually works. Both the battery and devices got charged simultaneously via solar.












Micro for the external power in this case solar and standard USB for outgoing power.







I did test an Iphone 4s and protected 18650 battery using a high efficiency 14 watt Allpowers folding solar panel charger from 10:25 am to 12 PM. The phone and battery were connected via pass through with a single USB port. At 10:25 am the 18650 was 3.7 volts, phone 59%. At 12 PM the 18650 was 4.1 volts, phone 91%. 




> 1. A battery must be placed in the slot in order to charge an external device through USB.




I am not so sure about that if my interpretation of what's written is correct. Seemed to charge without a battery so long as connected to power. Maybe it was slower but again hard to say. No reason to do it anyways.







Field use applications.


With the BIG power of 18650 batteries and the devices using them it's not hard to see the attraction of using them within outdoors and preparedness applications. For example I put the charged 18650 battery into my Nitecore HC30 headlamp.







But it can also work as a power bank for my phone in the field.












It also charged my Ipad from dead to 35% which is about right for a 3400 mAh battery.












The pass through charging capability is great for times when only one plug is available which happens more often when on the fly. In the coffee shop before a night hike. I am using a public magnetic charging ring. This option is not sold for the F1 however did work just fine. Charging both the battery for the headlamp plus an Ipod 6 which is used to keep track of data like distance hiked etc etc etc. Or browsing the forums on their WiFi without sucking down the phone battery.







Pros and cons.


Pros.


1. For the most part it provides a great control over energy in the back country as I hoped.


2. Very ultra light and small.


3. With rubber band the battery is very secure.


4. Simple to use. 


5. Inexpensive but seemed well made. I don't think this will just fall apart but time will tell.


6. The pass through charging is both useful and fun.


7. Acts as both a charger and power bank.


8. Solar compatible.


9. More options in field use. I can take the battery directly from my flashlight to charge the phone. I can use the extra batteries for the flashlight or headlamp to charge my phone. I can take the battery from the charger to power the flashlight or headlamp.


Cons.


1. With the batteries I tested sometimes not all the features operated 100% per the manual. Nothing which overly harmed the field use but a few inconsistencies such as the low capacity battery charge termination and low voltage cut off which worked but not always exactly the same way. For example it could terminate the charge around 3.3 rather than 2.8 volts and charge again if plugged back in for a time or maybe not. That said the features did work. It was always able to detect low capacity batteries. It didn't really use the low capacity batteries as a power bank and did actually cut off at low voltage. It generally put in the correct amount of charge for battery capacity when used as a power bank. 


2. Didn't come with a USB cable but got so many already.


3. Without the rubber band it can easily toss the battery.


Conclusion. 


It's a winner IMHO. 


Here is a video of the evaluation and field testing.


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## TinderBox (UK) (Jun 13, 2016)

Thanks for the great review, I have an F1 on pre-order from GB :twothumbs

John.


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## ChrisGarrett (Jun 13, 2016)

Thanks WW, your threads are always informative and superbly illustrated.

I'm checking my stuff out now, for hurricane season.

Chris


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## pyro0 (Jun 13, 2016)

Thanks for the nice review. 

Which solar panel is that? I never owned one and might plan to in the future, but don't know which to get or stay away from.


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## TinderBox (UK) (Jun 14, 2016)

When buying travel solar panels unless weight is a real problem, get a 3 (15w) or 4 (20w) folding panel, The one in the review is most likely 10-15w as it`s an 2 panel folding type, when buying solar alway buy a panel 2 to 3 times more powerful than you really need as the manufactures show the maximum wattage under ideal lighting conditions that normal users do not see, have a look on Amazon they sell a lot of different sizes, I bought an Cozypony 24W Solar Panel, (it`s a 4 panel folding type it`s more like 20w)

John.



pyro0 said:


> Thanks for the nice review.
> 
> Which solar panel is that? I never owned one and might plan to in the future, but don't know which to get or stay away from.


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## Woods Walker (Jun 14, 2016)

pyro0 said:


> Thanks for the nice review.
> 
> Which solar panel is that? I never owned one and might plan to in the future, but don't know which to get or stay away from.



I actually tested it using two. An Allpowers 16 watt 4 panel and an Allpowers X-Dragon high efficiency 14 watt which is shown in the video. Owned them both for over a year and have video reviews on them if you're interested. The 14 watt is more than enough but agree with TinderBox that when it comes to solar more is always better unless like me weight is a consideration.

Thanks for looking. Also thanks to everyone else as well. I appreciate the kind words.


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## brighterthanthesun (Jun 17, 2016)

Does the F1 always charge the cell in the cradle at 1 Amp or does it automatically detect small cells and charge them at a lower current?


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## TinderBox (UK) (Jun 18, 2016)

According to the specs in the PDF, The F1 can detect smaller cells and charge them at 500ma.



> *F1 can automatically identify the type of the installed battery. Under sufficient input power, F1 will charge a
> battery of large capacity in the slot with 1000mA current, or a battery of small capacity in the slot with
> 500mA current.*



https://www.google.co.uk/url?sa=t&r...sg=AFQjCNHYt9SBmpECK6asUVbFARjmjzaiTw&cad=rja

John.



brighterthanthesun said:


> Does the F1 always charge the cell in the cradle at 1 Amp or does it automatically detect small cells and charge them at a lower current?


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## sidecross (Jun 18, 2016)

This seems to be the charger/USB battery bank I have been looking for my solar charging needs. The build quality looks quite good, and the read out to 1/10th​ of a volt is a great feature. I have ordered one for myself.

To the size of how many watts a portable solar panels for hiking is a calculation between weight and time to charge batteries. The higher the wattage and efficiency of solar panels would be less time needed to be in an ideal sun location.

An evaluation of battery power usage needed, the time needed to charge batteries, and the opportunity for available sunlight are the consideration to be made on how many spare batteries to have.


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## HorizontalHunter (Jun 18, 2016)

Thanks for the review WW. I have been looking at it and debating about picking it up. 

That is a lot of flexibility for short money. It is miles ahead of the battery charger I have been using on my day trips.

bob


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## sidecross (Jun 18, 2016)

TinderBox (UK) said:


> According to the specs in the PDF, The F1 can detect smaller cells and charge them at 500ma.
> 
> 
> 
> ...


Thank you for the link. :thumbsup:


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## sidecross (Jun 19, 2016)

I received this charger and it is quite good, but I will use only batteries up to 18650; I was hoping to use 26650 batteries, but the charger being so light and with a weak rail spring, 2650 batteries would be difficult to load in the field.

The weight of a 26650 battery is 96 grams and the weight of the charger is 29 grams.


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## davidt1 (Jul 9, 2016)

Got one yesterday. Used it to charge my flip phone and a Logitech wireless keyboard. Then charged the battery. Everything works as expected. Main selling points for me are the small size and powerbank. Now only if it charges Eneloops too.


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## nfetterly (Jul 9, 2016)

Thanks for the review. Looks pretty good for the price.


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## TinderBox (UK) (Jul 12, 2016)

I wondered how many % of charge i would get from an 3400mah cell, when charging my tablet which has an 7900mah battery, I got a 23% charge before the F1 shutdown.

John.


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## sidecross (Jul 12, 2016)

TinderBox (UK) said:


> I wondered how many % of charge i would get from an 3400mah cell, when charging my tablet which has an 7900mah battery, I got a 23% charge before the F1 shutdown.
> 
> John.


At least Nitecore designed the charger so to prevent a 7900mAh tablet battery to charge the battery in their charger.


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## TinderBox (UK) (Jul 12, 2016)

It's amazing that you can charge an 7900mah battery with only an 1amp charge rate, though the battery is actually two cells in parallel as far as I know.

John 



sidecross said:


> At least Nitecore designed the charger so to prevent a 7900mAh tablet battery to charge the battery in their charger.


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## SeanAU (Jul 15, 2016)

Sorry if this isn't the right place, but I asked Nitecore on their facebook page if they were looking at making a 2-cell version of this charger (an F2?) and they said yes we will see it shortly.


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## davidt1 (Jul 15, 2016)

If Nitecore can add nimh charging capability, I would be very happy. I would buy two and call it a day.


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## TinderBox (UK) (Jul 16, 2016)

I would like to see NiMh support as well, but i think the power bank feature would not work with an single 1.2v cell once boosted to 5v you would get very little energy out of it when compared to an 3.7v li-ion cell.

John.



davidt1 said:


> If Nitecore can add nimh charging capability, I would be very happy. I would buy two and call it a day.


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## davidt1 (Jul 16, 2016)

TinderBox (UK) said:


> I would like to see NiMh support as well, but i think the power bank feature would not work with an single 1.2v cell once boosted to 5v you would get very little energy out of it when compared to an 3.7v li-ion cell.
> 
> John.



Of course one would not expect any powerbank function from NiMh. That's what li-ion is for.


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## Overclocker (Jul 16, 2016)

davidt1 said:


> Of course one would not expect any powerbank function from NiMh. That's what li-ion is for.


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## Andrey (Jul 18, 2016)

Make sure to check the F1 review by HKJ.


HKJ said:


> *Test/Review of Charger NiteCore F1*


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## davidt1 (Jul 19, 2016)

Tried charging a 14500 battery on an older laptop with only USB 2. The F1 worked. Charged the battery to 4.19.


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## jsackspot (Feb 27, 2017)

I'm just sad I'm now starting to learn about the 18650 "platform".

If I'd known then what I know now, I'd never have bought CR123 (16650) -based lights. What other goodies do people use as well (looking at the HC30, or H600)?

Also, what is magnetic charging ring; is that something more advanced countries have as a public service? 

Thanks all!


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## Arizona_Mike (Apr 15, 2017)

What kind of current are you getting from the F1? I think I recall seeing you are an Apple guy and I'm wondering if your iPhone is throttling to 500mA not recognising the power source.

I evaluated the THRUNITE U1 which will charge but not use NiMH in addition and can fit up to 26mm cells. It is high visibility orange and has a Velcro case to hold the battery in place. Unfortunately it is rated at only 1A capacity but identifies itself as a 1.5A+ USB power source by having the data pins connected. My Samsung Galaxy S7 tries to draw too much current and the voltage crashes and it cycles rapidly on and off above about 1.15A. I'm returning the two I bought to Amazon.

I may take a look at the F1.

Mike


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