Nitecore NU25 Headlamp Review

Nitecore NU25 Headlamp Review

This little Nitecore NU25 headlamp offers high CRI, with a built-in battery and micro-USB charging built-in, too. Read on for some testing!

Official Specs and Features

Here’s a link to the Nitecore NU25 Headlamp product page.


As far as emitters go, there’s only one version of the NU25.  But there are three body colors and two headband colors.  There’s black (seen here), yellow (which also has a black band), and white, which has a white band).


These go for $36.95 and may be purchased at

Short Review

This is a very fun little light.  I like the versatility offered with the emitter choices, and as a lightweight headlamp, it’s a good pick.  There are even some mods to make it lighter weight, too!!

Long Review

The Big Table

Nitecore NU25
Emitter: Cree XP-G2 S3
Price in USD at publication time:
Cell: Internal
Turbo Runtime High Runtime
LVP? Unsure
Switch Type: E-Switch
Quiescent Current (A):
On-Board Charging? Yes
Power off Charge Port with no Cell? Yes all modes available
Claimed Lumens (lm) 360
Measured Lumens (at 30s) 397 (110.3% of claim)^
Claimed Throw (m) 81
Candela (Calculated) in cd (at 30s) 223lux @ 2.648m = 1564cd
Throw (Calculated) (m) 79.1 (97.7% of claim)^
All my Nitecore reviews!

And just a few facts about the High CRI emitter, though most of this will be blanks…

Nitecore NU25
Emitter: High CRI
Cell: Internal
Claimed Lumens (lm)
Measured Lumens (at 30s)
Claimed Throw (m)
Throw (Calculated) (m) 6.7^
Candela (Calculated) in cd (at 30s) 9lux @ 1.119m = 11cd

^ Standard measurement disclaimer:  I am an amateur flashlight reviewer.  I don’t have $10,000 or even $1,000 worth of testing equipment.  I test output and such in PVC tubes!!  Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).

What’s Included

  • Nitecore NU25 Headlamp
  • Headband
  • Charge cable (USB to micro-USB)
  • Manual

Package and Manual

The light is packaged in a blister pack, with an easy open-cut line at the bottom.  It gives a good display of the product and included items.

Here’s a link to the pdf manual.

Build Quality and Disassembly

The NU25 has a well-built feel but is still quite light (ie often very light stuff feels cheap, but this doesn’t).

The headband attachment is very easily removable and doesn’t leave too many remnants on the light itself.  Really just the two circles on the sides, and two ratchet points on the back.  I think that probably leads this to be very 3d-mount print-friendly!

The back has a honeycomb design, likely a weight-saving consideration.  But since that area will be resting on the headband, which will be on the forehead, it’s also a good sweat exit point.

The halves of the NU25 appear to be ultrasonically welded, so I did not disassemble the light.

Size and Comps

Length 55.5mm
Head Size 55mm
Weight 28g

This headlamp is quite small.  A bonus fact about this light that I’ll cover more later is that it can be powered through all the modes from the micro-USB port.  So it’s possible and reasonable to power it with a battery pack (making the small cell size almost irrelevant.)

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

Retention and Carry

The light comes attached to this base, which is the connection point to the headband.  But don’t discount this base – the light pivots in it and for certain applications, this is a nice item.

That clip is also extremely close to being a functional belt clip, too.  I tried it and it works fine but it’s not technically secured to the belt.

But of course, primarily it’s a headlamp.  The included headband is nice.  It’s thick, and there’s a small silicone band for gripping the forehead.  This doesn’t go all the way around the headband.

Power and Runtime

This light is powered by a “2.26Wh” internal lipo battery.  I didn’t take the unit apart, so I didn’t see the cell.  The cell is not replaceable but is rechargeable.

I did two runtimes.  Turbo and High.  First is turbo – output is over 400 lumens initially but drops off pretty quickly.  In my test, the light never shut off but was well below 10% of 30s output when I stopped the test.

The High runtime looks very similar, and also never shut off.  Output starts a little lower than Turbo and drops off a little less dramatic, but still, the drop is severe.

I didn’t runtime for the High CRI emitter, because the output is too low for any sort of good graph.  And the red is very bright (and probably runs a little hot), but my sensor isn’t sensitive to red.

There isn’t any LVP.  It’s possible to check the battery level, but only when the light is off.


Recharging happens over a micro-USB port.  The port is covered by a thin strip rubber (probably really silicone) cover.  This cover stays in place well and is a little hard to get out of the opening.

A cable is included, and like most Nitecore cables, is a very nice cable.  There’s a velcro loop to keep it bound up if so desired.

These two charge graphs look different, most likely because of how far the cell was discharged during the runtime tests.  Charging is fairly good, and more or less confirms the 2.26Wh claim Nitecore makes about the cell.

Pulse Width Modulation

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.

There’s no noticeable PWM on any of the modes or white emitters.  (Again, I wasn’t able to test red, but it didn’t appear to have PWM.)

User Interface and Operation

There are two buttons on the top of the NU25.  Both e-switches, both moderately clicky with very low travel, and both indicating switches (though they seem to indicate from the same emitters, not individually).  One is labeled with a power symbol, and the other with an “R.”

Unsurprisingly the “R” switch controls the red emitter, and the other controls both white emitters.

Here’s a UI table!

State Action Result
Off Click Power Button (PB) Main Emitter On (low)
On (Main) <3s Click PB Main Advance (LMH Off)
On (Any) >3s Click PB Off
On (Any) Hold R Off
Off Hold PB Aux White
Aux White Click PB Low Main
Off Click R Red Low
Red Low <3s Click R Red Advance (Low High Caution)
On (Any) Hold PB Turbo (Main emitter)
Off (but not locked) Hold PB >3s SOS
SOS Click PB (within 3s of clicking for SOS) Beacon
Any Long Press Both Switches together Lockout (Click switch – red blink indicates lockout)
Lockout Long Press Both Switches together Unlock
Off Hold R Power indicator^

^ Power indicator
3 flashes = battery >50%
2 flashes = battery <50%
1 flash = battery <10%

LED and Beam

The main emitter is a Cree XP-G2 emitter with a lightly orange peel reflector. The other two-a red and a High CRI are unspecified. The High CRI is a larger rectangular either though, and a little unusual.

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure.

Tint vs BLF-348 ( 219b version) (affiliate link)

I compare everything to the Killzone 219b BLF-348 because it’s inexpensive and has the best tint!

Random Comparisons and Competitive Options….

Here’s a link to a relevantly filtered page on  I use that site a lot!

It’s all Nitecore items!!


What I like

  • Multiple useful emitters
  • Pretty good UI
  • Very small
  • Can be powered from battery pack

What I don’t like

  • A magnet would be nice
  • The headband working properly as a belt clip would be even nicer


  • This light was provided by Nitecore for review. I was not paid to write this review.
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3 thoughts on “Nitecore NU25 Headlamp Review”

  1. 28g weight is without the headband, the headband weighs another 25g! Lots of modders and sellers have made much lighter headband for this light from shock cord, e.g. has one which is 31g including their ultralight headband (looks like a Petzl Bindi). This light is very popular with the ultralight crowd so it seems important to mention the headband weight.

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