Klarus G10 USB Rechargeable Flashlight Review

It was some time ago that I reviewed the Klarus G20, a full-featured flashlight with a simple interface and a gloriously bright beam. Well, even though it’s been awhile, the “G series” is still alive and prospering! Enter its smaller and only slightly less intense relative… the Klarus G10!

The G10 Package

The G10 comes with everything you’ll need to get the flashlight up and running.

Accessories include a 3600mAh 18650 battery, a USB charging cable, an attached pocket clip, a lanyard, a belt holster, spare o-rings, and the user manual.  🙂


The Cree XHP35 HD E4 LED

  • Weight, w/battery; 4.56 oz
  • Length; 4.7″
  • LED; Cree XHP35 HD E4
  • Working Voltage; 2.5 – 8.4
  • Beam Distance; 250 meters
  • Body Material; T-6061 aluminum alloy; TypeIII hard anodized
  • Lens; Scratch resistant toughened glass — AR coated


  • Two independent power switches
  • Mode Memory
  • Four lighting modes & two emergency modes
  • Lock-Out Mode
  • Intelligent Temp Protection System
  • Battery Capacity Indicator
  • USB rechargeable
  • Impact Resistant to 1 meter
  • Waterproof to 2 meters (underwater); IPX-8

Batteries, Modes and Output

Inside the tail cap

The tail cap switch

In charging mode

USB port






The Klarus G10 is compatible with several battery types.

ONE: 3.7v 18650 (included); TWO: 3v CR123; TWO 3.7v 16340; TWO 3.7v 18350

There are FOUR regular modes: Low; 10 lumens. Medium; 100 lumens. High; 400 lumens. Turbo; 1800 lumens

There are TWO emergency (flashing) modes: Strobe; 1800 lumens. SOS; 100 lumens.

Runtime ranges from 1 hour on turbo, to 170 hours on low.

Battery Voltage Indicator

Each time the G20 is turned on, the little indicator in the center of the side-switch lights up. Green means the battery is 70-100% full. Orange; 30-70%, and Red, if less than 30%. If it’s 10% or less, the indicator will be flashing in red.

Klarus G10 with 18650 battery

G10 and battery

Lock-Out Mode

To prevent accidental activation in a pocket or such, hold BOTH switches at the same time for a few seconds. The light will respond by flashing three times. It’s now locked. To unlock, click either switch THREE TIMES FAST… and you’ll be signaled that it’s unlocked.

USB Charging

In case you’ve forgotten, the Klarus G10 has an internal charging circuit. Connect the micro USB cable to the port located on the opposite side of the side-switch, and the other end to a USB power source. The battery is now charging…and you’ll know it, because the little indicator will be red. Once it changes to green, you may disconnect the plug. A charging source current of at least 1A is recommended. Lower currents will extend the time it takes to charge the battery.

Basic Operation

First of all, to insert the battery, loosen the HEAD portion. The tail cap is NOT removable!

There are two switches on the Klarus G10; side and tail. Each perform basically the same way, but each are unique to different functions.

Instant light in the lowest mode can be achieved anytime the light is OFF by clicking the tail switch. Press and HOLD the same button to turn it off. Once ON in low, you can advance the mode by clicking either switch. Press and HOLD either switch to turn it off. The sequence is lowest to highest. From whichever switch you use to turn it on with, you can continue with the OTHER switch, without lowering the mode.

For strobe, double-click. This works whether it’s OFF or ON. For SOS…double-click again. A single click from SOS, returns to the previous mode. Both flashing modes are also accessible from the tail switch, however it seems to require an exceptionally fast set of clicks to activate them. Sometimes, it just turns on low instead. I would recommend to always use the side switch for that action.

The Klarus G10 Beam

Klarus G10 on medium

On medium

On high

Klarus G10 on turbo

On turbo


Klarus G10 on high


On low

High mode

Klarus G10 on turbo


Klarus G10 on high

High mode

Klarus G10 on turbo

Turbo mode

Low mode


Klarus G10 on high mode

High mode






















The Final Analysis

I like the Klarus G10 quite a bit.

Someone that DOES need mentioning though, is the fact that at low and medium output levels, PWM (pulse width modulation) has been detected. In case this is an unfamiliar term, it’s the strange looking effect you get, when illuminating a rapidly moving object directly in front of the flashlight. To some people, this can be a game-changer. To others, it can be just occasionally annoying. It can also be noticed when taking pictures or videos of the beam.

Among the positives, is the flexible switching system, and the VERY nice beam pattern. Being USB rechargeable is another plus, as is the presence of the battery voltage indicator.

Purchase Link

So now, if you like the Klarus G10, and would love an opportunity to own it, please click here 🙂


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  1. Klarus specs state the maximum runtime using the included 18650 battery is 170 hours vice the 17 hours your review states. What method did you use to conduct your runtime testing?

    I am highly interested in this light. My Klarus G20 and G30 (both passed on to friends) were stellar performers. My G20L is the same. Klarus usually delivers outstanding value for money in the world of high performance flashlights.

    • Thanks Jim, and I apologize…. that was just a typo! It reads 170 now, which is correct.

      I’m glad the other Klarus lights worked well for you. They DO make a nice product 🙂

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