# Nitecore NU20 Headlamp CRI review.



## Woods Walker (Mar 25, 2017)

Nitecore NU20 Headlamp CRI review.


For full disclosure these samples were sent to me from Nitecore for review.







http://flashlight.nitecore.com/product/nu20


Information from Nitecore.




> Features ·Highly portable headlamp:
> 
> 
> ·Multiple color temperature options available
> ...




Also Nitecore has the following runtimes listed for the CRI version and constant current no PWM.


1 lumen 100 hours.
30 lumen 7:45 hours.
170 lumens 6 hours.
270 turbo 30 minutes based on calculations. 


So how do these claims hold up to actual field testing? The headlamp was designed for running but also used it for camping. First lets take a look at the headlamp. These are in CRI. It is so small and UL.







The reflector offered a good mix of throw and flood for running the trails and streets in my area.







The Nichia 219B LED looks centered with no obvious defects in the reflector or blemishes behind the window. For those who like the Nichia 219B the tint does not disappoint or at least I wasn't disappointed in the way it showed the true colors of bacon but that's coming up.







The back when attached to the headband. Hope I did it right.







Speaking of headbands this one is wide and comfortable. It's also big enough to fit my block head with more than enough extra room for adjustment. This is one of my biggest concerns for a headlamp. A good headband can make or brake it in terms of field effectiveness. However comfort can be subjective. For me this is a home run. So comfortable I feel asleep wearing it during one outing. 







The harness has a physical lockout feature which proved 100% effective in my testing. Lock out is an important feature for me as often toss lights into a pack when on the fly. 







The beam angle adjustment is done via two hinges and two friction points if I am using the right words to describe them. It took me two hands to adjust the beam angle when on the move as there isn't much headlamp mass to counteract the force needed for the adjustment. It doesn't slip during running.












The headlamp's Micro USB port cover.







and port.












With the physical characteristics out of the way time see if the claims hold up in field use. The first thing is charging. As the battery can't be replaced wanted to do some of the testing in field conditions. Nitecore claims it will charge in two hours. Here is what I found when charging if the light is off. The stated charge time was confirmed.







The switch turns red when charging.







Yes it will charge from a powerbank. In these cases the Nitecore F1.


Charging and running.







Just charging.







The light will operate when plugged in. Seems to operate at a max of medium if out of power running off a powerbank however does it charge and run at the same time? The answer is yes but appears to do it if running on low. I think it might be charging on medium as well but if so it would be at such a slow rate as to be not practical. On low it seemed to charge just fine.

Running on low and simultaneously charging test. Might seem like a strange test for a running headlamp but if pressed into other service it's a good feature. On a side note the USB cord hangs down the user's face if employed as headlamp when running off a powerbank but makes for a good handheld light or hands free if you don't mind the cable. This is more of an exceptional extra use type thing IMHO.

When plugged into a power bank running on low the UI button illuminates red however it's actually charging at a reasonable rate unlike my testing showed for medium.







Once charged it turns green just like having it plugged into a standard USB power source with the headlamp off.







After done the green light will turn off then fade. Many powerbanks terminate the charge once the device's battery is full so the light will stay on. 







Bottom line. You can use it on low and it will run and charge at the same time. On medium not really.

So is there PMW? I did the shake and cellphone camera test using two devises. Also am sensitive to PWM so often see it when others can't.

On low there is no sign of PWM.






On medium there is something but not sure if it is actually PWM. Looks very similar to something I seen on my SC5w and didn't think it was actually PWM. Also could not detect it with the shake test. So can't say for sure but the cameras are picking up something. Just not convinced in my experience it is actually PWM. Maybe those more familiar with this technical aspect could key in.







The runtimes. 

The price for the CRI is reduced efficiency so this headlamp has lower overall output but for the same time duration. I didn't bother to test if the 1 lumen would last for 100 hours. Sorry my short attention span just won't allow for that but did test the medium 30 lumen/7:45h and 170/6h. The 270 for 30 minutes is based on their calculations so didn't verify that.

Medium mode.







Still looked about regulated however began to drop soon after this photo. I ended the test with the light still functional but clearly in need of charging so there was some life left in it.







High mode. I ended the test with the light still functional but clearly in need of charging. 







I didn't take a photo of the beam output as it looked a bit below the medium. So what happened? Per my hack math 600 mAh at 3.7 nominal volts is 2.22 watt hours. I don't know the draw of the headlamp but do not believe a Nichia 219B or Cree XP-G3 S3 can run their respected listed high output modes regulated for the entire time. So it steps down but does actually produce light at the 6 hour mark. It's probably within the rules for industry standards but just be aware it will not run the high regulated for the full 6 hours per my observations. Overall I am happy with the runtimes given the very small size of the headlamp and it's intended purpose.

Solar charging:

Did some solar testing of the Nitecore NU20. Seemed solar compatible using a 14 watt panel. I was unable to induce a charging error though your mileage might vary. This is one pro to USB powered devices. Charging from powerbanks and solar.







Solar Controller is missing an (o). I never noticed that before.







I didn't time it but charged good.






Water resistance testing.

The NU20 is IPX7 and 1.5m drop rated so decided to test both in actual field use conditions. First I would run 8 miles in the cold rain then drop the headlamp lamp multiple times in the roadside puddles. Jogged on both black top and dirt roads. Due to conditions only took the cellphone as it has a protective case.

















One of 3 or so puddles tested for both drop and water intrusion.







Then left it out over night on the porch in the cold rain.












So what does running 8 miles in ice rain and slush feel like? It profoundly sucked. I liked nothing about it beyond the fact the NU20 survived the drops and water. I wasn't surprised the drops didn't harm it given the very low mass but was surprised no water got in. Sure it is IXP7 rated but still I am happy.

Up next was 5 miles through the hills trail running with mircospikes. Temps in the teens. Way better than 8 miles through the ice rain just above freezing but the terrain was harder. As this is a running headlamp most of the field testing was done on the fly but also took it camping Still it is a running headlamp so kinda had to run.







The low 1 lumen mode.












Plenty to walk around in and root through the pack back but wouldn't run on slippery ground with 1 lumen.







Medium.







High.







High projected a bit further.







Turbo.












Nichia 219B field application. Is it worth the reduced output?

Medium. Trail marker colors look true.







Medium. PSK high visibility paracord looked good.







The following is compelling proof of CRI's value. Look at how the bacon appears natural in the medium mode.







Fearing this might be just the camera I used another camera and verified what my eyes and the other camera were saying.






But how does cooked bacon appear under the illumination of a Nichia 219B?





Looks good with second camera as well.






Pros and cons.

Pros.

1. Two LED options.
2. Fast charge times.
3. Long regulated medium mode.
4. Very small and UL.
5. Comfortable.
6. Built in battery.
7. Nice beam for running and even camp work.
8. Very bright and nice low.
9. Will run when plugged into a powerbank. Will charge and run on low mode.
10 Headlamp angle doesn't slip when running. It stays put.


Cons.

1. Built in power source might be problematic as can't immediately change the battery.
2. The UL design means it is made out of plastic. Is what it is.
3. Is there PWM on that medium mode? Not sure. Don't think it is true PWM but something is going on.
4. The red flashing lights do work to indicate power to some degree but given their limitations can't be exact.
5. USB port position makes it difficult to wear and run off a powerbank at the same time.
6. Often takes two hands to adjust headlamp.
7. Yes it is a running headlamp but would love if they made a UL camping version with a 10 lumen mode. This isn't really a con rather a wish.

Conclusion. 

I like it.

Here is a video.


----------



## kalel332 (Mar 25, 2017)

The problem with Nitecore is that their customers service sucks


----------



## stephenk (Mar 26, 2017)

Thanks for review. I'm currently in the middle of a review of the NU30, and Nitecore seem to have done a good job with the NU range.


----------



## FlashlightR (Mar 26, 2017)

Great review, thanks!


----------



## Hooked on Fenix (Mar 26, 2017)

I'm curious if your light on high was regulated at all or if it lasts so long regulated then drops down to near 10% for the rest of the runtime. My NU20 lasts about 1.5 hours to 10% brightness. It's fully regulated for around `1 hour 10 minutes. I wonder if they changed the light or if thermal protection kicked in on yours.


----------



## Woods Walker (Mar 26, 2017)

Hooked on Fenix said:


> I'm curious if your light on high was regulated at all or if it lasts so long regulated then drops down to near 10% for the rest of the runtime. My NU20 lasts about 1.5 hours to 10% brightness. It's fully regulated for around `1 hour 10 minutes. I wonder if they changed the light or if thermal protection kicked in on yours.



Do you have light around the 6 hour mark on high?


----------



## KITROBASKIN (Mar 26, 2017)

Good to see real-world use. Hope you are OK if I add some more real-use comments:

Just received a NU20 CRI yesterday (from illumn), had a chance to go remote but slept at our cabin. Nice headlamp as reported by WW. Not sure I'll ever use the SOS mode, but the slow beacon may be useful (from off, hold to get SOS then click off then click once to get beacon)

It seems sometimes the switching gets confused or I am not clicking right; nothing conclusive.

The color temperature is more warm than the three TIP CRI's in our possession and I think most Nichia users would be very pleased. The caption under WW's third picture in his review is missing the word 'not' as in, not be disappointed about the tint, I think.

No surprise that the NU20 throws a little more with a tighter (but still pretty broad) hotspot than a TIP CRI; should be fine for most tasks, with improved reach for night runners. 

The user interface is easy enough to get used to. The blinking battery status seems to be most conveniently accessed by holding the switch from off, and releasing as soon as you see the first blink. If you hold longer, SOS mode will start.

No problem charging directly from a Goal Zero 15 watt solar panel, even with filtered sun. (Successfully topped off a TIP CRI in filtered sunlight as well)

Works great used for ceiling bounce. The housing can be laid flat on a table, but switch access is blocked. Using it with just one notch opened is good. The notches feel sturdy.

Curious that 5 TIP's that have gone through my hands all arrived with an estimated 50% charge. The NU20 came nonfunctional until charged which took a little over two hours. I am hoping the battery was not stressed...

The comment about Nitecore customer service in post #2 is not a factor if one purchases from illumn or nitecorestore, my experience, having made no-fuss returns to both of them.

Though I prefer the cleaner white coming out of the TIP CRI, and the overall experience/design objective of the TIP (love the user interface), the NU20 has a lot going for it. Seems the decent headband is big enough for a hard hat. Accidental activations with this headlamp should not be an issue, if stowed with the switch in the covered position.

No evident sign of PWM in any mode.


----------



## Woods Walker (Mar 26, 2017)

I am going to test charge both the TIP and NU20 with an Allpowers 14 watt high efficiency panel. Good to hear no charging errors with intermittent light for you. I didn't check the level of charge for the NU20 as plugged them in till green from the get go.


----------



## KITROBASKIN (Mar 26, 2017)

Thanks again for the review, and just wanted to clarify: I charged under consistent filtered sunshine but did not test with intermittent sunlight. The TIP sailed through that but forgot to check the NU20. I used an Xtar USB voltage detector for the end of the NU20 charge, just to check up on it- All Good.

Also planning to use a smaller portable solar panel (~5 watts) in the near future.


----------



## Woods Walker (Mar 27, 2017)

One project I wanted to do is solar powered backpacking. Can someone really start out empty and keep their electronics charged (phone, lights etc) on the fly in real field conditions. Decided lithium ion was a better way to go than AA NiMH (F1 vs Guide 10 Plus). So one consideration is a headlamp and light with built in power supply and USB chargeable. But on the flip side the F1 can directly charge a 18650 and cellphone at the same time so the battery could go into the headlamp. Not sure the direction I want to take it but will probably shoot for some days and lots of miles out. Will have to see how the TIP and NU20 charge with broken light aka on and off as this would be a common issue when pushing through the woods before my final consideration.


----------



## Woods Walker (Mar 27, 2017)

On a side note corrected the typo. The tint does NOT disappoint. In fact it's rather good. No matter how many times I read this stuff over there is always something...... LOL!


----------



## KITROBASKIN (Apr 7, 2017)

Looking forward to that solar powered backpacking project. Of course, anyone deciding to try this out would choose to balance out components with (flashlight and phone) needs and available sunlight for the duration of their adventure, taking into account how much weight they are willing to carry. Seems like no wrong answers, maybe just a question of efficiency.

Seems like the Nitecore NU20 would be a good candidate for around-the-campsite and navigation but a compact thrower of some kind would be in my kit (amount of throw capability dependent on the terrain; forested or more open)


----------



## LED_Power_Forums (Apr 15, 2017)

Woods Walker said:


> On medium there is something but not sure if it is actually PWM. Looks very similar to something I seen on my SC5w and didn't think it was actually PWM. Also could not detect it with the shake test. So can't say for sure but the cameras are picking up something. Just not convinced in my experience it is actually PWM. Maybe those more familiar with this technical aspect could key in.



This, I guess it might be similar to what selfbuilt had encountered with his Fenix LD12. You can take a peek at his explanation(sort of) here:

http://www.candlepowerforums.com/vb...5)-Mini-Review-RUNTIMES-OUTPUT-MEASURES-VIDEO



selfbuilt said:


> I will explain what is going on in more detail below, but the take-home message is that the LD12 is most definitely NOT using PWM for its low modes - but it does have a reoccurring signal present in the Med-Turbo modes in the frequency range that can be perceptible as "flicker" for sensitive individuals.
> 
> Scroll down to post #2 for a detailed discussion of what PWM is (and isn't), and what to look for in oscilloscope traces. But to summarize, PWM is never present on Max, has a constant frequency and amplitude across lower levels, has a square wave pattern, and is only variable for pulse width. In contrast, my LD12's reoccuring signal is the opposite of the PWM - it is a signal of variable frequency and amplitude, has a sine wave pattern with nearly perfect periodicity (i.e., shows constant width), and is present on the Max level but not Lo. Here's a close-up of the LD22 Hi mode:


----------



## Hooked on Fenix (Apr 16, 2017)

Sounds like it uses a form a rectified alternating current as opposed to pulse width modulation as a way of dimming (The negative part of the sine wave is blocked by a rectifier diode in an alternating current circuit. This keeps the l.e.d. from getting fried). That's just my guess, but if they are using that as a way of dimming, I'd imagine they may be able to adjust more than just the frequency (such as the voltage) to make the circuit more efficient. Again, I'm just speculating.


----------



## rickypanecatyl (Apr 17, 2017)

A bit off topic, but what are you using that looks like a yellow rubberband in the picture showing your powerbank?


----------



## Woods Walker (Apr 17, 2017)

rickypanecatyl said:


> A bit off topic, but what are you using that looks like a yellow rubberband in the picture showing your powerbank?


Nitecore F1 flexible charger/power bank running a 3500 mAh naked 18650.


----------



## Woods Walker (Apr 17, 2017)

Adding it also running a Nitecore 3400 protected 18650.


----------



## Woods Walker (Jul 6, 2017)

Solar charging info updated add.


----------



## NPL (Jan 31, 2018)

Using the headlamp for more extended time, I noticed that on high mode, the output drops significantly and close to medium mode even after 1 minute. Although the tint, weight and price are great, be aware of this because Medium mode seems to be the highest mode that is regulated. I don't see the point of having a turbo because the High mode is already essentially, just that. I am disappointed by this and if I had known, would have bought something else.... This was noticed indoors. I don't know if it will behave differently outdoors in colder temps. I doubt the light has thermal regulation. I suspect it is simply a poor quality driver being used.


----------



## KITROBASKIN (Jan 31, 2018)

Had to get another NU20 because of premature battery death. Thinking the turbo mode is essentially a WOW mode for show and quick glimpses. Was thinking my wife would like this as a headlamp but it did not work out. It is now bedside where occasionally it provides ambient light.


----------



## Woods Walker (Jan 31, 2018)

I don't think the Turbo was meant to be used for more than a short time. It has no real heat sink so that's just a reality of what it is. I still use mine and the battery is holding up. It gets mostly used for an occasional short street jog or as a backup light that is very UL.


----------



## NPL (Jan 31, 2018)

Woods Walker said:


> I don't think the Turbo was meant to be used for more than a short time. It has no real heat sink so that's just a reality of what it is. I still use mine and the battery is holding up. It gets mostly used for an occasional short street jog or as a backup light that is very UL.


Which is fine and how most interpret how Turbo works. My pet peeve is that high behaves similar to turbo and steps down significantly. Anybody else notice this?


----------



## Woods Walker (Jan 31, 2018)

NPL said:


> Which is fine and how most interpret how Turbo works. My pet peeve is that high behaves similar to turbo and steps down significantly. Anybody else notice this?



I covered that in the review:

*High mode at 5:46h*

"I didn't take a photo of the beam output as it looked a bit below the medium. So what happened? Per my hack math 600 mAh at 3.7 nominal volts is 2.22 watt hours. I don't know the draw of the headlamp but do not believe a Nichia 219B or Cree XP-G3 S3 can run their respected listed high output modes regulated for the entire time. So it steps down but does actually produce light at the 6 hour mark. It's probably within the rules for industry standards but just be aware it will not run the high regulated for the full 6 hours per my observations. Overall I am happy with the runtimes given the very small size of the headlamp and it's intended purpose."


----------



## Woods Walker (Jan 31, 2018)

On a side note I am not a fan of the industry standards for stating output/runtimes. ANSI or whatever. It allows for too much confusion for consumers IMHO and over inflating of expectations by manufactures.


----------



## NPL (Jan 31, 2018)

Your review was great, didn't mean to undermine it in any way. Just thought this would be the right thread to add my direct feedback. Still a great little light.


----------



## Woods Walker (Jan 31, 2018)

NPL said:


> Your review was great, didn't mean to undermine it in any way. Just thought this would be the right thread to add my direct feedback. Still a great little light.



I didn't take it as that way brother.  You are correct in that the stated run times for the upper modes are misleading and this is as good of place as any to talk about it.


----------



## defloyd77 (Mar 13, 2018)

Just got an NU20 CRI a few days ago, I'm really loving this thing. Totally agree with the need for a 10ish lumen mode though and since this is supposedly a running light primarlily, it should have a slow flash instead of SOS. Personally, I'd ditch the short running 270 output, make 170 turbo, 40 high, 10 medium and 1 low. Much more practical in my opinion. As long as it remains reliable though, I'm totally happy with it.


----------

