REVIEW: ThorFire KL02 Single mode 17340 LiFePO4/16340/CR123 area light.

This is my quick review of the ThorFire KL02 light. Here it is with an Eagle Eye A6, a Manker AAA and my Carmex for size.

This is a single mode (for now… mwahahaha) area light that takes either a CR123 or a 16340 battery. I have some 16340’s on order, both LiFePO4 and 3.7V LiIon, but for now this light is running well on an “expired” (12-2013 good by date) CR123. It is pulling around 40ma on this old battery that was reading 2.99V prior to the testing.

The light activates by screwing the base all the way down, simple and reliable. There are no springs in this light, instead ThorFire has gone the foam doughnut route (mmmmmm, foam doughnut), and the tail has a center post surrounded by the foam.

This works very well on other lights like the DQG’s and keeps the battery from rattling in this when it is off. There is nothing to this light electrically, it appears to have the board press fit into the light from the front, with an LED emitter and a single resistor as the only circuitry. If there is anybody that can help with deducing this electrically, let us know, but it looks like a simple resistor circuit to me. Looks nice for modding as well…

The anodizing looks good, the knurling is enough, but not sharp and the threads and o-ring grooves are smoothly cut. Well manufactured for sure. Next to my DQG Tiny III 18650…

The front dome is thick, over a 1/4 inch thick in the middle, the plastic is frosted and the threads are deep and well cut.

There is an o-ring on the front as well, so this light should be pretty good with even a dunking in the water, a quick check in the shower for a couple of minutes seemed to do no harm… A simple and robust design. The supplied clip is adequate, but there are four holes for lanyards on the tail and they would be big enough for plenty of options. I wonder if a Convoy S2 clip, shortened, would fit?

More modes may be in order for some, but for a glovebox, purse or camping light like this, simple is better in my opinion. I believe it is rated for brighter output on the 16340 battery, but the run-time will be less, and then you have to have a charger, know LiIon battery dangers/chemistries, join BLF, get a few C8’s and other lights, take apart old laptop batteries for “pulls” and well, you know….you are here reading this…. Fun, aint it?

Seriously, if you want a light for someone to just have, throw a CR123 in this and forget about it. My quick math of ” 1500mah “: for a CR123 divided by conservative 45ma that the light draws is showing about 33 hours of use prior to a new battery needed… that is a pretty good number, but correct me if I am wrong…

This is a great light at a good price, I would not pay more than about $10 for this light personally, but is is a good bargain none the less for someone that wants a small area light. These are available on Amazon right now, and I have inquired if BangGood is going to carry them as they have told me ThorFire is their brand (apparently GearBest was poaching their images/sales).

Thanks for reading this mini review, I will post more when I get the other batteries.

Nice review, thank you for posting !!
This light is tiny. I didn’t think it would be shorter than Manker.
When you get your 16340’s, would love some reading on those as well.

Question how do you think this light would do as a neck light ??

I will post the 16340 results, I have both 3.7V LiIon and 3.0V LiFePO4 batteries on the way.

I think this would do as a neck light, but it is 23mm diameter, so it will not hide easily like the DQG fairy, and may hurt if you lay down on it. I would want a wider, flat lanyard, like the ones office workers wear for their ID badges to make it long term comfortable, but it would be wearable.

Thanks for the review. Always good to learn more about unusual flashlights.

reminded me of this one: Maratac TLL Strobe Light | Flashlights | Pocket Flashlights | Drop

I like these style lights, and long runtimes.

thanks for the review!

Thanks Rolz, that is why I like this forum so much, so much to see and learn…

I will do some longer term testing on the endurance of a CR123, but the theoretical is pretty good. I like that Maratac as well, but this one is easier to carry, and affordable for me. I think the frosted dome type of light is interesting and useful, with a hat brim clip, this would be a great headlamp… I used my DQG Tiny III with a silicone diffuser for just that purpose setting up a camp last week, worked great clipped ABOVE the brim…

Thank you for the reply and the review. I think this light could prove to be very useful.

Ill have to check when I get home but I want to say in ran well less than 20 hours on a keeppower 16340… And it was very dim during the last few hours. I did a video runtime test, before it crapped out.

I would expect 6-8 hours of useable light on a 16340, theoretically. I will run not comprehensive tests over the next weekend and update here…. I need to find my QTC pills I bought off member 18650 a month or so ago, this this may be the light for them…

I like dedicated lights such as this! Do they make one in other battery setups as well?

Not that I have seen, just the 16340/CR123. This is my first light for this battery size in 15 or so years, the last was an incandescent Streamlight Scorpion. I think for what it is, this is the best battery for this type of light as far as capacity and size. For someone not into flashlights a CR123 is a put it in and forget about it option, too easy…

So I did my first mods to this light. I was messing around and found out with a little tweaking, my Hugsby P31 (single AA light) clip would fit the KL02 body. A couple of bends later, it looks like it could be a useful clip.

Good luck to get this one off, it seems to be very strongly clamped to the body, I had difficulty lining it up with the top of the aluminum.

The next mod was to drop a piece of QTC into the tail cap.

PRESTO… Multi-Mode light unlocked, sort of… I can get a stable low of about 1/3 the total output of the normal “on” output.



Hard to get it to show, but somewhere between 1/4 and 1/3 the output of the normal on, I need to improve my camera skills….

Anything lower than about 1/3 can be finicky and flicker or change modes… This quantum stuff is always in a flux it appears… Actually it seems the threads and battery/foam pressure all add up to be too large of a tolerance to hold evenly. This stuff is the python of the electrical world, the more you squeeze it, the less resistance you get…

Above 1/3 brightness, a little careful twisting will get you whatever level you want, until you bump the light… I am happy that I can get a lower level that is fairly steady, but have no way to measure draw on this…

Enough fun for today, thanks to Mhanlen’s giveaway, I will be getting his broken one in a few days to see what I can do. I am thinking it will be my 500th post giveaway once I get it fixed/modded…

EH, the QTC is a bust. Took the light camping this weekend and the QTC was too finicky to hold a level, its outta there…. The clip was very handy, clipped to the brim of a ball cap, it functioned as a headlamp quite admirably. A deeper clip, like on an OLight would have made it better, had some light in the eyes during use as the light diffuser was past the end of the brim… Nothing an extra business card from the wallet wouldn’t fix. Put up the tent in a mild downpour with it on, so the O-rings work…

It works great as an area light and a walking to the bathroom area light, etc. This is a great little light… Now if FastTech would get those batteries to me…

I am thinking that simply replacing the resistor would allow you to change levels, go with more resistance to lower the light if I recall my electrical knowledge correctly… There is enough room in there to do this I believe… I will try it later this week perhaps.

These are Trustfire 700mah (rated at 600mah by Fasttech, and a non affiliated link for your pleasure… ) and they are brighter than the CR123’s. I will complete some run test times on them, but am concerned about pulling them too low as this is a simple resistor circuit.

I have one on the way from Banggood. Appreciate all your testing! Thanks. Interested in your runtimes.

I got in some 17340 LiFePO4 batteries from FastTech (HERE not an affiliated link). I charged them on a Nitecore D4 I just got and loaded one up. They fit first of all, and there is not enough room for an 18350 it would seem, but a 17340 is skinny enough. The LiFePO4 is the 3.2V “lithium ion” battery type (not 3.7V like the “normal” LiIon). I went with these as it seems they are a bit better for lower discharges not hurting the chemistry like it does a standard 3.7V LiIon. As this is an unregulated resistor circuit and will suck the battery down until it dies (~2V or so…) I figured this LiFePO4 type chemistry would be better for a light like this. The caveat, you have to have a charger that can SPECIFICALLY charge LiFePO4 batteries (Such as my Nitecore D4).

I ran the previous 16340 unprotected batteries for over an hour, but the light was warmer than I was comfortable with to continue. It was not burning hot, but for an area light that may be hanging somewhere in a tent or what not, too hot not to react if your head touched it. While a jumping reaction is funny in the sitcoms, knocking yourself and your tent partner out with the coconut sound of your melons colliding is not… Worst case scenario, yes, but still not why you want this little light.

The run time on the LiIon 3.7V was more than likely as long as Mhalen showed in his video on this light. I did not have a protected 16340 and so did not want to run it to lights out…

The run time test on the LiFePO4 3.2V is still on going as I write. The light got warm, but not really that far above room temperature, perhaps 90-95F. Great light output for the first three hours, greater than the 3V CR123 disposable battery. It will not have the run time of the disposable though. It is only rated at 350mah compared to the 1500mah of the CR123 disposable.

I used a singe 3V CR123 disposable, that was over a year past its “use by” date, for the four day weekend on July 4th. I was camping and used the light the entire weekend for miscellaneous tasks, and as a “candle” for a few hours each night. Dimmer by the end of the weekend, but still plenty of light.

While I will finish this run time experiment tomorrow for the LiFePO4, to me the winner for use in this light is already clear: The disposable 3V Lithium Primary CR123 battery. You have no worries with the disposable battery, they will last OVER ten years in a glove box or other place and still give you light. No chargers (special ones in the case of the LiFePO4) needed. Even retail you will be buying perhaps $5 worth of batteries every couple of years of intermittent use in a purse, glovebox or backpack.

If you plan to use this light frequently, and you have a LiFePO4 charger, get some 17340’s and enjoy the light. 16340 protected are too long (per Mhalen) and the 16340 un protected get pretty warm and you could damage the battery from over discharging it.

My opinion on a nice little light, thanks for reading!

I have a couple of CR123A primary cells, used, rated at 1400 mAh. They tested at about 2.9 V At what voltage are these no good at?

How long are u saying that the KL02 will run on one of these cells???


The light was pulling less than 45ma on my cell, but 1400mah/45ma draw= 31 hours run time, in theory. I have over 12 hours on my CR123 and it is still chugging along fine. Not as bright, but still plenty of light.

As for the voltage, no idea, more than likely ~2.5 or so, but throw them in and run them till they drop!

EDIT: The 17340 LiFePO4 lasted about three or so hours at a decent level. I turned it off over night and back on again today. The light is dim after about three more hours, enough for a total dark situation, but I would say it is time to throw the LiFePO4 on the charger now. A quick check on the D4 shows 2.51V, so that is about it. Just over six hours on a LiFePO4, not bad.

This will conclude my review of the Thorfire KL02

SIMPLE, one mode, one battery, no springs or switches to wear out. Good attachment points on the tail.

One mode…. No clip… No real upgrades to do (yet)…

Hard to beat this for a glovebox, purse, backpack or other stow-it-and-forget-it light. Especially equipped with a standard CR123. The light will give over 12 hours on a single CR123, and possibly much more, so it is a good light for emergencies, etc. The dome is nice for an area light, and works fine for other more specific tasks like reading, but has no throw to speak of. Get a couple if you need a light to throw a battery in and forget about…

Thanks for reading!

much appreciated for doing the math on that.

The resistor reads 1R1, which should be 1.1 Ohms. This cannot be, can it?

I bought one and plan to replace the LED by two or three of rngwn’s LEDs in parallel (already took care for groups of similar FW). But LEDs, a CR123 and one 1.1 Ohm resistor will instantly fry the LED, no? I would have understood if it were 1K1. Is it?