fenix lr40r art photo

Fenix LR40R Rechargeable Flashlight Review

Fenix LR40R Rechargeable Flashlight Review

The Fenix LR40R is a rechargeable 12,000-lumen flashlight offering spot and flood, USB-C charging, and powerbank features.  Absolutely impressive!  So many features, testing took much longer than usual…  Read on!

Official Specs and Features

Here’s a link to the Fenix LR40R Rechargeable 12000 Lumen Flashlight product page.


There’s just one version of the Fenix LR40R.  There is at least one other very similar model, though.  The LR50R is very similar, also claims 12,000 lumens, but has just four emitters and deeper reflectors for each.


The price of the Fenix LR40R rechargeable 12000-lumen flashlight is $269.95.

Fenix LR40R Rechargeable Flashlight Short Review

My mind was a little blown with all the features this light packs.  A throw emitter.  Eighteen spot emitters.  Very good USB-C charging.  Not just USB-A powerbank capability, but also power delivery powerbank ability (up to 12V!).  This light offers so much!  And does it all very well, too.

Long Review

The Big Table

Fenix LR40R Rechargeable 12000 Lumen Flashlight
Emitter: Both
Price in USD at publication time: $269.95
Cell: 4×18650 (Included battery pack)
Turbo Runtime Graph
LVP? Switch indicator, switched to low output
Switch Type: Dual E-Switch
Quiescent Current (mA): ?
On-Board Charging? Yes
Charge Port Type: USB-C
Charge Graph
Power off Charge Port Lowest two Spot modes
Claimed Lumens (lm) 12000
Measured Lumens (at 30s) 9414 (78.5% of claim)^
Candela per Lumen 26.7
Claimed Throw (m) 773
Candela (Calculated) in cd (at 30s) 4220lux @ 6.049m = 154411cd
Throw (Calculated) (m) 785.9 (101.7% of claim)^
All my Fenix reviews!


Fenix LR40R Rechargeable 12000 Lumen Flashlight
Emitter: Cree XP-G3 (Flood)
Price in USD at publication time: $269.95
Cell: 4×18650 (Included battery pack)
Turbo Runtime Graph High II Runtime Graph
LVP? Switch indicator, switched to low output
Switch Type: Dual E-Switch
Quiescent Current (mA): ?
On-Board Charging? Yes
Charge Port Type: USB-C
Charge Graph
Power off Charge Port Lowest two Spot modes
Claimed Lumens (lm) 11000
Measured Lumens (at 30s) 8449 (76.8% of claim)^
Candela per Lumen 3.3
Claimed Throw (m) 410
Candela (Calculated) in cd (at 30s) 1190lux @ 5.168m = 31783cd
Throw (Calculated) (m) 356.6 (87% of claim)^
All my Fenix reviews!


Fenix LR40R Rechargeable 12000 Lumen Flashlight
Emitter: Cree XP-L HI (Spot)
Price in USD at publication time: $269.95
Cell: 4×18650 (Included battery pack)
High Runtime Graph
LVP? Switch indicator, switched to low output
Switch Type: Dual E-Switch
Quiescent Current (mA): ?
On-Board Charging? Yes
Charge Port Type: USB-C
Charge Graph
Power off Charge Port Lowest two Spot modes
Claimed Lumens (lm) 1000
Measured Lumens (at 30s) 1052 (105.2% of claim)^
Candela per Lumen 115.8
Claimed Throw (m) 640
Candela (Calculated) in cd (at 30s) 3160lux @ 6.044m = 115435cd
Throw (Calculated) (m) 679.5 (106.2% of claim)^
All my Fenix reviews!

^ 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

fenix lr40r what's included

  • Fenix LR40R Rechargeable 12000 Lumen Flashlight
  • Fenix ARB-L37-12000 Rechargeable Li-ion Battery Pack
  • Charge cable (USB to USB-C)
  • Lanyard
  • Nylon carry pouch (formed, not soft)
  • Spare o-ring
  • Manual etc

Package and Manual

fenix lr40r manual

Build Quality and Disassembly

fenix lr40r feature photo

Off the top, let me say that the build quality of the LR40R is great.   It’s sturdy (heavy, as it should be).  Everything that should be smooth is smooth.  Everything that should be accessible is.  The switch sits up just the right amount.  The charge port cover sits just right.  There’s just so much “right” here.

For a can light, the LR40R offers some unusual features, too.  So many features.  More on that later.

From the top down, have a look.  First, the bezel has reliefs – it’s not a “flush” bezel.

fenix lr40r bezel

The cooling fins extend all the way from the head down to the switch area.  Some of them are moderately deep, too, offering great cooling capability.

fenix lr40r cooling fins

The switch area is on the head, exactly opposite to the charge port.  More on this later, but note that the flood and spot have separate switches.  This light operates like two flashlights!

fenix lr40r e-switch

The battery tube is mostly featureless.

fenix lr40r body

Here you can see the tailcap, which isn’t removable.

fenix lr40r tailcap

fenix lr40r tailcap

fenix lr40r tailcap lanyard holes

fenix lr40r tailcap

More detail on the cooling fins.  Those around the head, where most of the heat will be generated by the flood emitters, are deep.

fenix lr40r cooling fins

fenix lr40r cooling fins

Cooling fins around the switch and charge port (approximate depth of the spot emitter) aren’t quite as deep.

fenix lr40r indicator

Both switches sit a little proud.

fenix lr40r switch profile

Fortunately, the charge port has a very accessible press-in cover.  Sometimes I have to fight with these things, but this one is a pleasure to use.

fenix lr40r charge port closed

It’s proud too.

fenix lr40r charge port profile

Under this cover are the USB-C charging port, and the USB-A powerbank port.

fenix lr40r charge port and powerbank port open

In the center is the spot emitter, a Cree XP-L HI.  The ring of 18 emitters around the edge is Cree XP-G3.

As stated above, the bezel has some features, which means when placed head down, light will escape.

fenix lr40r headstanding

Fenix provides a battery with this purchase.  More on this later.  This is 4×18650 cells.

fenix lr40r battery pack

The only part I was able to disassemble on this light was simply removing the head from the body.  Threads here are very smooth, and not very long.  They’re anodized, square-cut, and easy to start.  The bezel or the tailcap don’t remove (at least easily, or without other tools.)

fenix lr40r head off body

Looking into the cell tube, you see a nice feature.  That center peg will prevent incorrect installation of the battery.

fenix lr40r into cell tube

At the base of the cell tube, you can also see four springs.  It is possible to use your own 18650 cells in this light, with an asterisk (more later).  Fenix recommends their 18650 cells (4 ARB-L18 18650 rechargeable batteries), if you aren’t using the provided battery.

fenix lr40r into cell tube springs and head contacts

The head doesn’t have any springs.  But note that there is an “extra” contact point here (right in the center).

fenix lr40r head contacts

fenix lr40r with battery

The battery only works in one way (both electrically and physically), but it isn’t keyed.  As long as positive is up, it’ll fit.

fenix lr40r battery install

fenix lr40r battery installed

fenix lr40r battery installed

Above the switch is a four LED indicator.  I’m still calling this a “switch indicator” since it’s built right in with those two switches.

fenix lr40r indicator switch

fenix lr40r emitters

fenix lr40r tailstanding

Size and Comps

Officially 154mm x 80mm x 51mm.  And without the battery, the light weighs 500g.

If the flashlight will headstand, I’ll show it here (usually the third photo).  If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).

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

And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

fenix lr40r beside torchlab boss 35

Retention and Carry

Likely the main way you’ll want to carry the LR40R is with the included nylon pouch.

fenix lr40r in nylon pouch

This is an unusual pouch, in that it has a form fitted hard section for the body, and a velcro band that secures the head.

Of course, this means installation is only in the orientation shown.  The light can be removed from the pouch without loosening the velcro band.  Or at least removal depends upon how tight you’ve made this strap.  It can be either way really.

Also included is a standard lanyard, which connects only through these loops on the tailcap.

fenix lr40r tailcap loops

fenix lr40r lanyard installed

This setup does mean that tailstanding will be a little uneven.  I’d rather it be two holes so that the lanyard can go out the side of the tailcap, and still allow even tailstanding.  This is a very minor issue.  (I don’t use lanyards anyway!)

fenix lr40r lanyard installed

Power and Runtime

As stated above, the Fenix LR40R is powered by an included battery.

fenix lr40r included battery

This battery is an ARB-L37-12000, which is a 12000mAh battery pack, consisting of four 18650 cells.  Fenix states as compatible 4 ARB-L18 18650 rechargeable batteries.  Those are button tops, and if you bring your own 18650 cells to the game, you’ll need button tops too.

This included battery is quite different….  Technically it’s just a group of four individual cells (which doesn’t make it a “battery”) – the cells are in parallel.

But you see that center pin there?  That connects in some way electrically so that the light recognizes that “this is my battery” and that allows turbo to work.  Otherwise (otherwise being “anything that isn’t this battery pack”), you only have four modes of flood (and still get all four modes of spot).  Since the light ships with this battery, this isn’t the biggest problem.  But if you ever wish to swap in your own cells, be advised that you’ll lose Turbo.

fenix lr40r included battery

Installation is easy, and directional – as I said above, the battery will only go into this tube in one direction.  It’s physically blocked the other way.

fenix lr40r included battery being installed

fenix lr40r included battery installed

fenix lr40r included battery installed

There’s a battery indicator, too.  Clicking either switch will cause these LEDs above the switch to indicate how much charge is present, as follows:

Four blue: 100%-80%
Three blue: 80%-60%
Two blue: 60%-40%
One blue: 40%-20%
One flashing blue: 20%-0%

This feature only works with the included battery.

fenix lr40r battery indicator

Here are some runtimes.  I could have gone a number of ways with testing here, but I went with what seemed most logical to me.  The highest mode of Spot.  The highest mode(s) of flood (which overall offers much more total output).  And since the LR40R can be seen as two separate flashlights, and the total output and throw are also rated with “both lights” on their highest setting, I also tested this way.  Just one test like that though – highest spot along with highest flood.  After that, it becomes a bunch of “why not this why not that” because any mode of flood can be matched with any mode of spot.

Interestingly, when the battery voltage gets lower (around 3V), the light switches to the spot emitter, at around 60 lumens.  At this state, it’ll last for quite some time.

Another note here before we get started with the runtimes.  As mentioned above, the bezel has some relief – which I love.  That means it sits on a surface that light escapes and you’ll know it’s on if headstanding.  This does also mean that during runtimes, it’s not possible (with my setup) to capture absolutely all of the output.  You can note that as one reason some of the outputs below fall a little short of their claim.  I don’t fault the light for this, but my setup.

First, the Max Max runtime.  That is Turbo of the Flood 18 XP-G3’s, and High of the XP-L HI.  Output is rated at 12,000 lumens, and we do see nearly 10,000 lumens briefly.  Then the stepdown begins, to around 5500 lumens.  This is what the manual states, too.

fenix lr40r runtime graph max output

Now the runtimes with just the flood emitters (18).  I tested three levels – the highest three.  On the “Medium” output, I did not cool the light, so you might be interested to see how the heat builds up in that case.

fenix lr40r runtime graph flood turbo

fenix lr40r runtime graph flood high I

And “Medium” is really Medium – I seem to have spaced on running High I (which should be around 3000 lumens).  But this gives you a chance to see an uncooled run, at least.

fenix lr40r runtime graph flood high II

Here’s the runtime with the Spot emitter.

fenix lr40r runtime graph spot

That’s certainly not all the modes (and obviously not all the combinations of flood + spot), but I think it gives a good idea of what the light will do.

Also regarding low voltage protection – while the light steps down to Eco of the Spot emitter, the indicating switch is also blinking a single blue light (very quickly).  So there’s a warning, too.

Charging and Powerbank

Charging on the Fenix LR40R is by way of a USB-C port.  The port cover is quite secure, and also easy to open when needed.

Here’s the charge port.  Also note above the charge port is a USB-A port.  The USB-A port is the powerbank port.  Unfortunately, there is no USB-C output (which is the one feature I was surprised wasn’t implemented here.)

fenix lr40r charge port open

A charging cable is provided – it’s USB to USB-C.

I tested charging with the provided setup – USB to USB-C.  Here are a couple of tests with that:

fenix lr40r charge graph 5V usb

I also tested with a USB-C to USB-C cable.  That works fine too, but I don’t have logging capability with that setup.  I will say that based on my tracking of this setup, the charge profile with C to C looks the same as with the graphs above.  Same (approximate) current, for example.  Despite the powerbank feature being able to output up to 12V, the C to C charging was at only 5V.  The manual does state

USB Type-C port is used, and QC3.0, QC2.0 fast protocol or 5V adapter are supported, fast charging adaptor will be auto identified.

So I think I’m just not triggering QC3.0 et al properly… I’ll continue trying this and would love input on this from you all.

Speaking of the powerbank features, here are a couple of graphs displaying discharging the battery.  The powerbank can discharge a massive amount of current at 5V.  And also even at 12V, high current is possible.

That’s right, at 5V, the LR40R can output almost four amps, and the voltage doesn’t really even sag a meaningful amount.  At the end of that test (once the ~4A stopped), I turned the output back on to lower output, then did that again.  Finally, after 1A output, the cells were around 3.06V.  All in all, this is a very good result.

But since the USB-A port supports power delivery, I tested at 12V as well (it’ll do 9V, but I didn’t test that).  Again, the current output is fairly incredible, at around 1.25A.  At 12V, 1.25A is around 15W (which is approximately the same as it was doing on 5V output).  So it seems reasonable to infer that output is limited to around 15W-16W, whatever the voltage being used.

Modes and Currents


Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 11000 45m 8449 ^
High II 6000 2h 4552 9.30
High I 3000 2h50m 2259 3.81
Med 1000 7h15m 758 1.15
Low 350 22h44m 247 0.38

^ I am unable to test the current draw on turbo with my setup.  Turbo only seems to work with the proprietary Fenix battery, and the driver seems to sense this.  More on that in the Power section.


Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
High 1000 7h 1029 2.78
Med 350 22h30m 758 0.73
Low 150 44h31m 178 0.28
Eco 50 92h18m 68 0.11

Pulse Width Modulation

No pulse width modulation is seen on any mode.



For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  Also, here’s the light with the worst PWM I could find.  I’m adding multiple timescales, so it’ll be easier to compare to the test light.  Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, with is 50 microseconds (50us).  10ms5ms2ms1ms0.5ms0.2ms.  In a display faster than 0.2ms or so, the on/off cycle is more than one screen, so it’d just (very incorrectly) look like a flat line.  I wrote more about this Ultrafire WF-602C flashlight and explained a little about PWM too.

User Interface and Operation

As I’ve stated many times above, this light has two switches.  They’re e-switches, side by side on the head end of the LR40R.  They operate essentially completely independently, making this more like two lights in one.

fenix lr40r e-switch

The switches are just a little proud of the body (maybe 1mm).  They’re completely independent – when pressing one, the other one doesn’t move at all (as sometimes happens on dual e-switches that are this close together.  The button cover feels like (and almost certainly is) metal.  All in all, the user interface here is just great.

As can be seen by the lasered image on each switch, one is for flood and one is for spot.  In the image above, the left switch is the flood switch, and the right switch is the spot switch.  Just above these two switches is the four LED indicator.

Here’s a UI table!

State Action Result
Off Hold Either On (previously used mode for that switch)
Off Click Either Battery indicator (expounded upon above)
On – Flood Hold Flood Switch (0.5s) Off
On – Spot Hold Spot Switch (0.5s) Off
On – Both Hold Spot Switch (1.2s) Off – Both
On Click Switch corresponding to whatever’s on Mode advance (Low to High direction)
Any Hold Flood Switch (1.2s) Strobe (Flood only)
Strobe Click Flood Switch Strobe advance (Strobe>SOS)
Off Hold both (1.2s) Lockout
Lockout Click Either Spot emitter blinks twice to indicate lockout
Lockout Hold both (1.2s) Unlock to Spot
SOS Click Spot Switch Last used Spot

LED and Beam

There are a couple of sets of emitters on the LR40R.

First the spot, which is a Cree XP-L HI.  I happen to love that emitter, but this one is cool white.  I think 6500K is pretty common, and I’d guess that’s what this one is, too.


fenix lr40r spot emitter

This emitter is paired with a deep and wide very smooth reflector, which gives a nice tight hotspot.

fenix lr40r spot reflector

Next is the flood emitter set, which is 18 Cree XP-G3 emitters.  These are everything that XP-G3’s usually are.  But they output a ton of light.


fenix lr40r flood emitters

They have a very shallow reflector (each) and make an absolute wall of light.

fenix lr40r

fenix lr40r emitters

There are a few things I could wish about this light.  First of all, warmer emitters would be fantastic.  Even a Cree XHP35 HI for the main emitter – I think that would be an improvement.  Flat White?  Would probably make this light crazy.  Secondly, the Cree XP-G3 flood emitters…. I understand why to use those (output overall), but some emitters that have less tint shift and a better profile overall would please me much more.  It’d take this from being a light with great throw and high output to being a light with great pleasant throw and extremely high output and great temperature…. a real enthusiast light.

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




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

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.




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


What I like

  • So many features.
  • Seriously so many features.
  • The features that are included are all very well implemented.
  • No PWM
  • USB-C Charging
  • Great build quality
  • Powerbank feature really versatile
  • Very good charge port cover

What I don’t like

  • Cool white emitters
  • Somewhat confusing UI (alternate phrasing: UI requires memorization for some modes – it’s hard to just guess to get to the special stuff)
  • Turbo only available with the specialized (but included!) Fenix branded battery pack


  • This light was provided by Fenix-Store.com for review. I was not paid to write this review.
  • This content originally appeared at zeroair.org.  Please visit there for the best experience!
  • For flashlight-related patches, stickers, and gear, head over to PhotonPhreaks.com!
  • Use my amazon.com referral link if you’re willing to help support making more reviews like this one!
Liked it? Take a second to support zeroair on Patreon!

2 thoughts on “Fenix LR40R Rechargeable Flashlight Review”

  1. Pingback: Olight Marauder 2 Blue Flashlight Review - ZeroAir Reviews

  2. Pingback: Flashlight News: Phreaky Briefing Issue 41 – PhotonPhreaks

Leave a Reply

%d bloggers like this: