Review: Nitecore NU20 CRI (incl. Beamshots and X-rays)

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stephenk's picture
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Location: Australia
Review: Nitecore NU20 CRI (incl. Beamshots and X-rays)


This headlamp was kindly sent to me for review by Banggood.
Product page –
28% off Nitecore NU20 CRI code: 12da27
No other payment was received for this review. A free headlamp does not stop me from being critical if required during reviews.


The quality and functionality of headlamps on the market has improved considerably in the last few years. The Nitecore NU range, is a fairly new range of headlamps that have USB rechargeable li-ion batteries. USB charging is increasingly popular with the consumer market, as they don’t need to fuss around with cylindrical li-ion or NiMH batteries and chargers. The NU20 and NU20 CRI models are currently in the middle of Nitecore’s NU range.

High colour rendering index (CRI) emitters are very popular with flashlight experts (flashaholics), but have made limited in-roads into the consumer market, where the “lumens war” still drives sales. High CRI emitters allow for better colour rending of objects, in particular anything containing the colour red, compared to the “ghostly white” look of objects illuminated with commonly found with cool white emitters. One of the more popular high-CRI emitters is the 90+CRI Nichia 219B, and Nitecore have incorporated this into the NU20 CRI and NU30 CRI variant models, instead of the 70+CRI Cree XP-G2 emitter in the NU20 and NU30.

Below are the manufacturers claimed specifications.

Emitter Type: Nichia 219B
Material: Durable PC materials
Mode: Turbo,High,Mid,Ultralow +SOS Beacon
Lumens: 270LM,170LM,30LM,1LM
Runtime: 30min,6h,7h45min,100h
Battery Configurations: Built-in Li-ion battery
Switch Type: clicky
Switch Location: body of the headlamp
Peak Beam Intensity: 1200cd
Impact Resistant: 1.5meters
Range: 69meters
Waterproof: IPX-7 waterproof 1meter
Color: black,green,white,yellow,blue,red
Weight: 47g (with battery and bracket)
Size: 2.18”×1.29”×0.82”(with bracket)

- Highly portable headlamp
- Multiple colour temperature options available
- NU20 CRI: Fitted with a Nichia 219B LED, CRI≥90
- Built-in Li-ion battery provides runtime up to 100 hours
- Onboard USB charging circuit
- Single switch user interface design offers easy one-handed operation
- Built-in power indicator
- 4 brightness level and 2 special modes available
- Unique switch guard to prevent accidental activation
- Textured reflector ·52°adjustable illumination angle
- Made from durable PC materials
- Lightweight and compact dimensions
- Impact resistant to 1.5 metre


The NU20 arrived in a branded clear plastic and cardboard box. The box contained the Nitecore NU20 CRI USB Rechargeable LED Headlamp, Headband, USB cord, and a well written English Manual. Along with most USB flashlights, no plug was supplied, as most people have plenty of USB plug/chargers around the house.

Design and Ergonomics

The Nitecore NU20 CRI is surprisingly compact headlamp, with a plastic body, that tilts within a plastic shell. The emitter is located off-centre (on the left side of the body), with a USB port below, and button above. This layout is due to the 600mAh li-polymer battery taking up most of the right and middle of the body internally. The shell has allows the body to be tilted forward up to 52 degrees in 5 steps. For running I used the 3rd step down. There is a cover over the switch to prevent accidental activation, which also means that the light has to be tilted forward at least one notch to activate. Unlike the NU30, the body did not accidentally tilt further when pressing buttons. The body can be completely removed from the shell if required for lighting purposes other than a headlamp.

For night running, I found the NU20 CRI to be comfortable, and very lightweight. Due to plastic construction there was thankfully no wobble which can occur on tube shaped headlamps in rubber holders. The tilt angle stayed in position during the run. There is just a single (round the head) headband, which I personally prefer over the two band type (round and over the head).

Below is a comparison in size between the Nitecore NU30, NU20 CRI, and Thrunite TH20.

Below are some x-rays of the NU20 CRI’s internals.

User Interface (UI)

There is a single “power” button on the top of the light.

Single clicks of the power button will cycle the light through Low>Medium>High>Standby mode. After 3 seconds, the light will turn off if this button is clicked again. A long hold from on will take the light straight to turbo, which steps down after just 30 seconds. There is no single click access to turbo from off.

A very long (3 sec) hold of the “power” button from off, will cycle through SOS>Beacon modes. After 3 seconds, the light will turn off if this button is clicked again. The beacon mode has a short flash approximately every 3 seconds.

A long (1 sec) hold of the R button will display battery capacity remaining – >50% = 3 flashes, 10-50% = 2 flashes, <10% = 1 flash.

I found the UI easy to remember, though it helps that I previously tested the NU30!

The light can be operated when charging via USB, which is a big plus, and also means that the light can be run or charged from a power bank. When charging, the button displays red. When fully charged, it displays green. Charging from empty to full took less than 105 minutes using the supplied Nitecore USB cable and a 1A/5V iPhone 6 USB wall plug.

Beam Profile and CRI

The Nitecore NU20 CRI has a orange peel reflector, instead of the smooth reflector in the NU20 model. This allows for a slightly wider beam angle, floodier beam, and a less defined hotspot. I much prefer the beam profile in the NU20 CRI model than in the non-CRI model for running. The below photos show the beam profile of the NU20

Below is a beamshot comparison between Nitecore NU20 CRI (Left) and Nitecore NU30 (Right)

The specifications do not mention the CCT. In my sample was a 5000k emitter. This has a pleasant rosy tint. The high CRI beam (90+ CRI) is great for colour rendition. Objects with colours at the warmer end of the spectrum (red, orange, and yellow) are rendered much better than with the usual 70+ CRI cool white beams found on most lights. Aside from being more pleasant to look at, it is also critically useful for tasks such as checking that food is cooked on a camp fire, or for first aid purposes. When running the high CRI makes it easier to identify things I shouldn’t be stepping on, such as pesky cane toads, snakes, and spiders. The below photos show the difference between the Nitecore NU20 (left) and Nitecore NU30 (right) illuminating coloured blocks and my wifes hand. The third photo shows the NU20 CRI’s 5000k tint in comparison to the 4000k Nichia 219B Astrolux A01 (left) and 5700k (ish) Nitecore NU30 (right).

Output and Runtimes

As with the Nitecore NU30, I found the output to be higher than the manufacturers specifications. From low to turbo, I measured (via ceiling bounce tests) the outputs (@25s) to be 3, 30, 180, and 300 lumens.

Turbo mode drops from 300 lumens to 140 lumens between 30 and 60 seconds. Both turbo and high modes decline in a linear manner until around 120 minutes, at which point the output levels off at around 15 lumens. The light then runs at 15 lumens until around the 10 hour mark. I like the fact the NU20 CRI will not suddenly leave you in the dark unlike some headlamps. I would prefer a mode in the 50 to 100 lumens range, is this I find more optimal for urban night running (enough light, but not too much light).

In medium mode, the light runs at 30 lumens until around the 8 hour mark.

Low mode runtime was not tested, as it would have significantly delayed this review. The low mode makes for a useful night light, though at 3 lumens it is brighter than the specifications. No PWM was detected in any modes.


This has quickly become my favourite night running light, just edging the smaller but less powerful Fenix HL10. It is lightweight, comfortable, has a nice floody beam, and high colour rendering index (CRI). Due to the low/moonlight mode, and high CRI, it can be used as a light night, and is useful for camping, first aid, or other uses where telling the difference between colours is important.

Unless you need optimal throw, I would recommend the Nichia 219B emitter CRI versions of Nitecore NU20 and NU30 headlamps over the normal XP-G2 emitter versions. However, both CRI and non-CRI versions of Nitecore’s NU range are excellent headlamp options.

Outdoor beam shot – 6secs, f/5.6, ISO400, +0.5EV exposure in post processing.

Edited by: sb56637 on 09/02/2017 - 12:28
stephenk's picture
Last seen: 22 hours 42 min ago
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Location: Australia

Video added at last (at bottom of review)!

Henk4U2's picture
Last seen: 32 min 35 sec ago
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Location: The heart of the Netherlands (GMT+1)

Thank you for a nice review.

With X-rays: the final frontier.
To boldly go where no man has gone before.
Waiting for some ultra-sound and an MRI-scan.
Just kidding. Classical case of review-envy.

I always think long and hard before I say something really stupid.

Lexel's picture
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Location: Germany

Outdoor beam shot – 6secs, f/5.6, ISO400, +0.5EV exposure in post processing.

you mean 1/6s?

Xray loks like a plastic reflector?

stephenk's picture
Last seen: 22 hours 42 min ago
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Posts: 1303
Location: Australia

6 seconds, not 1/6 seconds. I’m very good at keeping still.

Noctiluco's picture
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Location: Spain

WOW, X-Ray pictures, Thumbs Up Thanks for the review

Last seen: 7 hours 7 min ago
Joined: 02/03/2012 - 15:52
Posts: 601

Very helpful review, thank you!