Klarus G20 Flashlight Review


I hosted a group buy recently (which is now closed) for this Klarus G20. That was popular so Kathy sent me one for review. I happen to like Klarus lights, so I’m glad to review this one!


There’s a coupon, which is unfortunately not quite as good as the group buy price. Still a great price, though! The coupon is only available via PM this time! Sorry! PM me if you’re interested.

Official Specs:

  • CREE Next Gen. XHP70 N4 LED; Up to 3000 Lumen output; Max runtime of 150 hours
  • Side and Tail Switch can access One-Touch Turbo, Tail Switch can access One-Touch Low mode
  • Independent Dual-Switch Control for Maximum Versatility
  • Side Switch memorizes current output mode for ease of use
  • Lock-Out mode to prevent accidental power-on and discharging battery for safety
  • Integrated Micro-USB charging port with up to 2000 mA charging current for extremely fast recharging (when used with KLARUS 2A adapter cord)
  • Intelligent Battery Capacity indication to display the remaining power level
  • ITS Temperature Control System guarantees safe operation and protects LED and internal circuitry from overheating
  • Aerospace Aluminum Alloy body; Mil-Spec HAIII anodizing for superior protection
  • Reverse-Polarity Protection prevents accidental damage from incorrect battery installation
  • Convenient Size, Easy to Carry
  • Anti-reflective (AR) coated mineral lens, hardened against scratches
  • Unique reflector design to attain both Spot and Flood beams with a perfect hotspot

G20 (SLIC): Super Bright; Long Runtime; Indestructible; Convenient

Warning: Use only 26650 Li-ion batteries in the G20 Do not use 18650/16340/CR123A batteries

  • CREE XHP70 N4 LED; 50,000 hours life
  • 4 output levels, 2 strobe patterns
  • Battery: Li-ion 26650 Battery x 1 (Use only 26650 i-ion batteries (included),Do not use 18650 /16340 / CR123A batteries)
  • Voltage Range: 2.5V – 5V
  • Dimension: Bezel 36mm (1.41″); Body 34mm (1.34″); Overall Length: 124mm(4.88″)
  • Weight: 131g (4.62oz) (without battery)
  • Material: Aerospace Aluminum Alloy 6061-T6, Mil-Spec HAIII anodizing
  • Lens: Hardened Mineral Glass; AR coated; Scratch resistant
  • Reflector: Orange Peel
  • Body Color: Black
  • Switch: Side Switch + Tail Switch
  • Protection: IPX-8 rating (up to 2 meters submersible)
Mode Output (lm) Runtime
Turbo 3000 45m
High 650 4.5h
Medium 160 19h
Low 15 150h
Strobe 3000 1.5h
SOS 160 51h


There is only this version.

Short Review:

I’m shocked at how bright the G20 is. And for how bright, how small. I was surprised how popular the group buy was, and now that I have the light, I understand it. Superb light!

Long Review:

What’s Included

  • Klarus G20
  • 5000mAh 26650 Cell
  • Holster
  • Lanyard
  • O-ring
  • USB Cable
  • Manual

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The normal host of photos, some beamshots to get you going, and a runtime to finish off.

Package and Manual

The Klarus G20 comes in a colorful display-ready package. I have a couple of Klarus lights, and this seems to be standard packaging in the red/black color combo. It’s a nice package and easy to open. Since mine came from GearBest, it does have a GearBest inventory sticker on the front. All the goods are contained in one of those little thin plastic trays.

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The manual is a single page to be unfolded, with English on one side.

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It does a good job of describing the UI and specifications of the light, and also some warranty explanations. It’s a good manual.

Build Quality, Disassembly, and Durability

I have not had a lot of Klarus lights but every one I have had, has great attention to detail and quality craftsmanship. This is no exception. The G20 has a very high quality feel, due in part to the anodizing, which has a thick, slick feel. The knurling is not grippy at all but the light is still easy to grasp. Everything about the build quality here is fantastic. I have one slight niggle with the side switch, however. There’s a good 1mm of play between pressing the button and the button activation. That said, it’s is a very predictable action. Once you hit the activation point of the switch, you know it: there is no confusion. I’d just like a tighter button here. (I liken it to a DSLR and the focus/shutter release button difference.) The click itself from the side switch is also quite loud. Same button on the tail switch, but it’s covered by a rubber boot so it’s not nearly as audible. These are not complaints on quality, they are expressions of preference.

Disassembly is mixed bag. The tail cap unscrews off easily, and the button is accessible. But it’s not a standard size button, so unlikely exchangeable. So let’s give this a “serviceable” rating. Then the tube unscrews from the head easily, but the head doesn’t easily release the driver etc. The side switch prevents that. I don’t see an easy to get the side switch off, but if you achieve that, I suspect the + switch and driver etc will slide right out (or unscrew). I also expect the bezel will unscrew if one has the right tools (or the right motivation). I gave it the ol’ [“A ‘C’ is passing”] college try, and failed to remove it. Before removing that though, I’d ask you, why would you want to remove that big ol beautiful XHP70?

The threads on the head side are very broadly square cut, but unanodized. The threads on the tail side are much finer but also unanodized.

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The micro-USB port is behind a very snug rubber boot. So snug it makes a little sound when you open it. Very nicely made.

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I was sitting here looking at this light, about to type “I might not use this as a gun light…” but then I though…. this G20 probably is honestly durable enough. Springs at both ends, a big ol’ thick one on the tail side…. This light is built like a tank. There might be too much play in the cell compartment, though.

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As far as 26650 lights go, the G20 is small. I really only have the Eagle Eye X7 to compare it to, but it’s shorter by almost a cm. It is however, 4 or 5mm larger in diameter. Still, in hand, the side switch falls exactly where it needs to for easy activation. Adding to the girth, and worth mentioning, is the aluminum sleeve that the cell resides in. The sleeve is what allows internal recharging of non-proprietary cells. So I applaud Klarus here for using this sleeve and not having some proprietary cell requirement.

I will gladly sacrifice a few mm any day in order for the onboard charging to work with any appropriate cell.

Quoted as 36mm (head) x 34mm (body) x 124mm long.


The G20 comes with a nylon holster and a lanyard. It feels robust enough to handle being thrown in a bag alone, and there is an electronic lockout, so that’s a reasonable possibility. And even though this light is quite large in diameter, it’s not so long to make short stints of pocket carry uncomfortable.

The lanyard connects via a hole on the tailcap – there is a hole on either side.

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Only one option for power, and that’s 26650. Klarus provides a 5000 mAh cell, and you’ll need to remove this pull tab before operating the light. There’s no good reason that a 18650 won’t work, but that will probably prevent onboard charging. The working voltage only covers single cell applications. But the manual expressly states not to use 18650, so please bear that in mind.

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There’s quite a bit of room in the barrel for the 26650 – even the Klarus provided cell. I’m a bit surprised by this, as I’d expect Klarus to provide a cell that fits more perfectly.

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There is a side mounted micro-USB charging port, claimed to be a “Fast Charge” port. That means it can charge at up to 2A. I don’t tend to charge anything at 2A, so I don’t care so much about that. Having said that, I can say that the 2A is probably temperature controlled. A cell may not like being charged at that rate, so it’ll respond with heat. It seems that the Klarus will slow charging to not overheat a cell. The reason I say it must not be solid 2A all the time, is that the indicating side switch says it took almost 8 hours to charge, from 3.3V, this cell. If it was stone cold empty, it’d need 5000 mAh (though, we know this is not the case, let’s just do some math). 5000 mAh @2A should take 2.5 hours. Since it took 8 (ish), we know it’s not 2A all the time. For what it’s worth, the manual does report it as “approx. 4 hours”

And based on the runtime (and claims) we can already say there is internal temperature monitoring, so maybe that the same chip is leveraged for both output and charging modulation.

Whatever the case, the charging took longer than I wanted it to, knowing the “Quick Charge” marketing. I’m pleased to have it as an option, and it does work quite well, but it seems a touch slow.

EDIT: I have since realized that my charge adapter was a 1A max adapter. So the slow charging is (likely) not due to this light. I expect the 2A claim is accurate. Sorry for this mistake!

User Interface and Operation

There are two switches on the G20. A rubber boot tailswitch, and a hard plastic domed side switch, which has an indicating LED in the center. The buttons work in nearly the same way, with at least one exception.

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State Action Result
Off Tail Click Low
Off Side Click Mode Memory*
Off Tail/Side Hold Momentary Turbo
Off Tail+Side Hold Lockout
Lockout Tail/Side Triple click Off
On Tail/Side Hold Off
On Click Advance to next higher mode (L>M>H>Turbo>L)
Any Double Click Strobe

* Strobe and SOS aren’t memorized

The first two options in that table make the UI very flexible. If you like mode memory, use the side switch (from off). If you don’t like MM, use the tailswitch (from off). The downside of this is there is no way to make Turbo stay on (though there is direct access to Momentary Turbo).

The indicating side switch is used for revealing current cell capacity. The indicator only works when a 26650 is being used. When the light is turned on, the indicator will light for a few seconds as follows:

Light Charge (%)
Green 70-100
Orange 30-70
Red <30
Red+Flicker <10

LED and Beam

There’s a big fat XHP70 nestled at the end of a short orange peel reflector. Even white wall hunting, I don’t see any cross shaped artifacts in the beam. As I said, the only other (single) 26650 light I have is an Eagle Eye X7 – these lights couldn’t be more different. The X7 is all throw (even though it has a short reflector), but the G20 is just a big wall of light. Unlike a can light, however, the reflector does direct some light, so there’s a fair bit of usable light downrange.

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Beamshots, Runtime, and Lux Measurements

I have two graphs here, of the same runtime. First a full runtime, and then a zoomed version so you can see what’s going on in the first minutes there. It’s easy to see the temperature regulation kicking in. This is not quite as clean regulation as something like a Zebralight uses, but it does seem to work quite well.

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Klarus G20
Emitter Cree XHP70
Emitter Notes N4
Cell 26650
Runtime 26650
Beamshots [0.3″, f/8, ISO 100, 5000k] 26650
Claimed Lumens (lm) 3000
Lux (Measured) 825
At (m) 3.12
Candela (Calculated) in cd 8030.88
Throw (Calculated) (m) 179.2303546
Throw (Claimed) (m) 150

Random Comparisons and Competitive Options….

The Acebeam EC50 Gen II is very similar to the G20. The Acebeam is a single switch light, and has some nice cooling fins (which make the head bigger than the G20.) The Acebeam is also fairly more expensive than the G20. The Olight R50 Seeker might weasel into this category too, but the output won’t be quite as much, and it is also a single side switch, and also more expensive.


What I like

  • Onboard charging charges any 26650
  • Build quality is superb
  • Output is great (it makes a lot of light. Seriously, a lot).
  • I like the mode memory/no mode memory option with the two buttons
  • The tint is pretty good. (I’m an XHP70 fan.)

What I don’t like

  • Slightly too thick for what it is
  • I’d like anodized threads
  • I wish the two buttons did more (It seems like they overlap in function most of the time.)


Coupon is only available via PM this time! Sorry! PM me if you’re interested.

GearBest has some other stuff going on too, have a look:

GearBest Black Friday Sale (Nov 24-28) and the LED LIGHT & Flashlight @ Black Friday Sale.

Parting Shot

In it’s natural environment?

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  • Some of the links here are affiliate links.


  • Changed wording of coupon.
  • I have since realized that my charge adapter was a 1A max adapter. So the slow charging is (likely) not due to this light. I expect the 2A claim is accurate. Sorry for this mistake!

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