Review: LetterFire LF-838, another fatty with a handle (+ simple resistor mod)

LED Flashlights – General Info 18650 Flashlights
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LetterFire LF-838

Reviewer's Overall Rating: ★★★☆☆

Reviewer's Mod Host Rating: ★★★½☆

Quick Summary:

Battery: 4x18650
Switch: Electronic sideswitch
Modes:

High, medium, low + hidden strobe
LED Type: Cree XM-L2
Lens: Normal glass
Tailstands: Yes
Price Paid:

This light was provided by Gearbest.com

Price: 44,25$
From: Gearbest
Date Ordered:

Ordered 4th april 2014

Received 24th april 2014

Pros

  • Mine came with XM-L2 emitters (description said XM-L)

  • 3 normal modes and hidden strobe

  • Centered emitters and good reflectors

  • Lots of flashlight for the money

  • Decent range (for a quad light with low current)

Cons:

  • Loose head. I had to turn/tighten it around 35 degree in order for it to be tightened, which makes the light look weird.

  • No lockout (batteries will always be drained when they are inside the light)

  • Weak output considering the size of the light (3,3A divided on 4 emitters)

  • Scratches and imperfections

  • Not waterproof

  • No charger circuit inside the flashlight (I would just avoid the charger)

  • Heat sinking could have been better (partially hollow pill, good enough for stock output though)



Introduction

I was approached by Gearbest to do a review on a light. I decided to go for it and chose the LetterFire LF-838 since I had not seen much info about these lights, and was curious about it. Hopefully others are too. It looked similar to Ultrafire S4 and some other lights, but Gearbest sold this light cheaper than I had seen others sell it these lights for. Less than 45$. Could it be a budget bargain? Its certainly one of the cheapest lights of its formfactor and size. Sadly Gearbest failed to my only request, so I had to pay about 33$ in VAT/Taxes for my "free review sample". No so free after all. But lets see what I got..

Unboxing:

Notice the loose charger..

Design/build quality: ★★★

Scratches on the head (from the charger?)

Its unique, and different, but I kinda like it. Its well balanced.The handle is a bit sharp on the edge, but not bad.

What I don't like is the loose head. It needs to be tightened. When its tightened it, it just looks wrong..

Some rubber to cover the charging hole on the bottom.

The button. (and some scratches on the head)

Some scratches on the handle too. (Only visible in the right light)

Mediocre tailcap threads. No lockout. Notice that piece of aluminium..

..lots of leftovers from the machine work..

Tailcap. This goes round and round when tightening it.

Contact path from circuit board to tailcap seems good when its tightened down. Its a large area.

Nicely centered XM-L2s. Nice surprise, because I though this came with XM-L emitters, like description and sales picture showed.

Glass is not AR coated like description on Gearbest webpage says (,and probably not toughened either).

One large MCPCB.

Lots of space between mcpcb and all the way down to the driver circuit. Pill is hollow, but the emitters are partially over thick aluminium. Thermal paste is used. Each emitter is given less than 1 amp, so heatsinking is adequate for the stock light. I would not have worry about increasing output in the light a bit either, but you cant make it into a proper hot-rod without some work to the head..

No O-ring in between the head and body.

Sense resistors. Its easy to bump up the current in this light.

Its also easy to ruin the electronic switch button wire if you decide to try and mod the driver without taking the driver out or being caution with the switch wire are a retard. Yeah yeah, I know. Should have taken the driver out first instead of trying to solder down there. But the retaining ring was not super easy to unscrew. I drilled two holes in it. That made it easy to unscrew and screw tightly back in.

Here is the switch:

You are not supposed to take it off the light.

UI

The light always starts on high. And you have to cycle through the tree modes in order to get to off.

High - 3,3 Amp

Medium - 1,7 Amp

Low - 0,4 amp

Its also got hidden strobe if you hold the button for about 1,5 sec in any of the three modes. Strobe is full output. When you exit strobe you exit to high-mode.

3,3 Amp dived on 4 x M-L2s is still more than 1000 lumen OTF. Enough to make any non-flashoholic seem very impressed with the light. Also, with 4x18650 and a low mode with 0,4A (when batteries are full), you will get very long runtime. Runtime is not anything special though. Its just average considering what it is.

Ill give ★★★½☆ for runtime based on amp draw. I did not perform any runtime tests.

As a flashoholic, I would say peak output is weak considering that its a decent sized quad XM-L2 light..

Mod/ increasing output:

I copper braided tailcap springs and changed to 18 awg emitter wire.

I did not care much for the drivers low output, so I tested with a bridge (literally) over one of the resistors and hoped the driver would handle it. With 4 NCR18650PF @ 4,12v emitter current was bumped up to about 9,4A on high. Medium was also 9,4A (same as high, so ruined) and low was 3,3A (way too high for a low) No good then.. No damage to driver either.

I removed the bridge and added one R100 on top of each of the two resistors (not pictured). This got me about 6,4A on high (sinking), 3,3A on medium (same as high was before), and 0,79A on low (double of stock).

The light now have pretty decent output, but low is not that low anymore.


Size comparison with other lights:

Here it is gathered with some other fatties with a handle. And a classic king for reference. (don't mind my temporary button on the LF-838. 0:) )

Lights below:

-LF-838,

-Solarstorm SP-03

- 5x XM-L2 Yupard (its actually a no name light, these go under many names)

- Another no-name cheapo XP-G thrower light

- Nage 3x XM-L2

- SRK 3x XM-L2

As you can see, compared to the Yupard and Nage, its a step up in size. And a SRK is a bit small in comparison.

Light output, tint and beamshots: ★★★☆☆ (stock)

Tint is just an typical CW tint around 6500K. Its not bad, for a CW, so cant complain.

Manufacturer rate the output to 4500 lumen.. 4500 LUMEN! Bwahahahha. At 0,825amp to each emitter? NO. About a 1000+ lumen, yes.

After the simple resistor mod it does have pretty good output though.

Here are some mouseover comparisons vs some floody rivals.

LF-838 at about 6A vs a the 5 XM-L2 Yupard (pictured above) at about 10A.

LF-838@6A vs 3x XM-L2 Nage at about 9A

LF-838 @ about 6A vs SRK at about 9A (SRK have 80+ CRI and is warmer)

All in all. Despite the "conservative" current at 6A (which could probably have been pushed a bit higher), its quite easy to see that the LF-838 have fairly good throw, but also not as wide spill as some of its more floody alternatives. Spill is more similar to a single emitter light, like a C8.

Value: ★★★½☆

This is a 44$ light. Mine came with 4x XM-L2 emitters. Its also a step up from a Quad SRK in reflector size and overall size. Its got several flaws, but at the same time, its a lot of light for the money too.


Detailed summary (numbers by me)

Power Source Options:

  • 4x18650 batteries in parallel (means you can use less batteries)

Switch type:

  • Electronic sideswitch

Modes, PWM, drain

  • Modes: High, medium, low + hidden strobe

  • Emitter Amps stock: 3,3 – 1,7 – 0,4

  • Current drain in standby: 0,0117A (measured after mod I believe)

  • PWM: 31.62 kHZ

  • PWM whine: No, not audible

Memory:

  • No memory, always starts on high

Dimensions:

  • Overall Length: 165mm

  • Height from top of handle to bottom of the light: 98mm

  • Head Diameter:81mm (widest part)

  • Body Diameter: about 54 mm

  • Tailcap Diameter: 54,9mm

  • Reflectors Inner Diameter: 26 mm

  • Reflectors Outer Diameter:27,7 mm

  • Reflectors Depth: 22,7mm

  • Reflectors emitter hole Diameter:8,9 mm

  • Lens Diameter: 4x 27,8mm

  • Lens Thickness: 4x1,5mm

  • Emitter star diameter: Special size

  • Driver diameter: About 44,3 (slightly smaller than typical SRK driver)

Misc:

  • Waterproof: No

  • Anodizing: Probably HA-II «light grey» + bare aluminium

  • Bezel material: Aluminium

Weights :

  • Overall: 564g without battery

  • Ready to use: 757g

Conclusion: ★★★☆☆

Getting a quad light of this size with 4x XM-L2s and a driver that have 3 decent spaced modes and hidden strobe is kinda impressive considering the price. It also looks more expensive than it is IMO (unless you are close and studying the scratches). Its also refreshing to see something a bit different than the usual black or grey standard looking lights. But, I can not overlook the several flaws of this light. I give it a decent and solid 3 out of 5 stars.

Reviewer's Mod Host Rating: ★★★½☆

Its an easy light to work on, good space inside, and easy to open. Although you might want to drill two holes in the locating ring in order to make it easy to unscrew and tighten. Its easy to double the emitter current in this light. And it seems to handle it nicely. You then get good output and a light that can handle 5-6A much better than a SRK sized light due to its physically larger size.

Making it into a hot rod requires more work with the driver (rebuild or replacement) plus work in the the head. And you might want to look into improving the head angle too, for better looks. And maybe the the lockout if it bothers you.

All, in all. A fairly nice mod host.

Ill keep mine lightly modded for now, and then Ill see if it take it further some time in the future.

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Interesting review…sad it came so neutered and with so many problems

I wonder if the Djozz drill out the center of the XM-L and rivet in a copper slug would help with heat

not hot on the Driver diameter: About 44,3 (slightly smaller than typical SRK driver)

the lobes on that dogbone looking star…are they standard 20mm star sizes as in would a single copper disk then solder on 20mm sinkpad/noctigons on the corners be a viable star mod

I like the though on the charge idea…but definitely NOT on the fact there is no intelligent CC/CV Li Ion charging pattern…with that I would bet 5vdc charger…without something there to control the charge pattern is a good way to blow some Li Ions up…NOT GOOD (can you give us a better shot of the driver…the IC’s in the background [all blurry] might could be some sort of charging bruhaha…I almost would bet against it though)

Excellent review! Very detailed

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Thank you for the review RaceR86.

It is a strange looking light in my eyes though. Even with the head still aligned.

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LetterFire should mean this?

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Thanks for the review RaceR86. There was no oring between the head and body but it looks like there is provision for one? Also is there any kind of anything to seal the bezel to the head? It looks like they have got the driver right in respect to three modes with hidden flashy's to be let down with poor output. I'd say we are getting closer to the ideal driver. If it has mode memory that is.

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thanks for the review RaceR. With all the pro's and contra's considered it is a real pain that you had to pay so much for taxes that could have been easily avoided by Gearbest .

Personally i can't get over my impression that it is really ugly .

@WarHawk: it was not me who did the copper rivet thing to led-boards (I am too lazy for that, I just use Sinkpads everywhere), it was Comfy.

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LetterFire eh?
It intrigues me because I’m a mailman. The price is right, but since I already have an EYE40, I don’t know whether I need another Quad.
I think I’d throw four Qlites configured to master/slave in there.
Too bad the emitters are all on a single MCPCB. There is a wide ledge they’re resting on though. That should absorb a good bit of heat. You may be able to install a tail switch for lockout.

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This looks like a good mod host to me. Aluminum discs could be added in the center to give even more thermal mass and to better heatsink the emitters (shame, looks like the thermal pad juuust barely rests on the thick aluminum shelf).

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Thank you.

About your questions. I would just make a aluminium pill on the lathe, or make a copper pill out of copper plates.. Ive done it several times before. Not too hard, and then I could replace with Noctigon.

Star size: The large diameter ring on your picture is about 40mm. The smaller ring is a about 24mm.

I did not take any decent pictures of the driver when it was out. But his shows most. The darker area around the sense resistor can easily be seen in the picture in my review.

Positive and negative on the charger input (plug) goes directly to positive and negative on the driver circuit.

Yupp, looks like there is provison for an O-ring. With a correct sized O-ring the head might have been properly aligned when tightened. No seal around the bezel to head. Only O-rings around lenses, not between head and bezel.

HOW DARE YOU CALL MY NEW LIGHT UGLY DOZZ!! ;)

Yeah, I would prefer to not pay the 33$. But only paying 33$ for this light, I cant complain. I just didn't bother putting full effort into the review. Most other lights in this class have flaws too.

The Yupard have considerably worse heatsinking stock since only a small edge of the floating mcpcb sits on top of an edge. Its also got more light loss due to bad head design.

The Nage seems quite good in terms of build, but the head on mine was glued. The driver on that light is not my cup of tea either.. Too much modes with silly stuff IMO.

Basically, these larger multiemitter lights in the 30-45$ range often have several flaws. Im kinda used to it...

Hey Ouchy. What do you get when you combine a Letterfire light with ultrafire batteres??

....

Mailbox fire! :D

haha.. Ok... maybe not so funny..

:p

Yupp. Nothing that cant be fixed..

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Well…one could always cut the + pin to the board, solder in one of those teeny USB Li Ion charge boards (with proper leads)…but as many has said…how can you guarantee the cells in the battery will stay connected while charging and charge them evenly.

Are you planning on modding it?

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Personally I would not even bother with charging batteries inside a light. I have proper chargers. Taking the cells out of the light, and putting them in to a decent charger is faster. And way safer.

Chances are Ill mod it properly some time in the future... Not now though. I have more interesting projects before that, and now that Im done writing reviews and doing various other mods I wanted to do. Time to start focusing on my scratch build.

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Just noticed that the light is in stock now. Gearbest claim its on 60% discount for the next 5 days. Which means the price is 44,25$. The same regular price when I got it. Not sure if you can use coupon code on top of that.

Not a fan of Gearbest to be honest, but the price isnt bad if you like the light.

Personally id probably go for the 4-XM-L Nage (terminator clone) instead. Not sure how good the pill design is though.

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The way that head is cut it looks like it’s designed to butt up against the O-ring that is not there. I’ll bet if you put a proper fitting O-ring on the housing the head will then line up properly and eliminate the over rotation.

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Yupp! I think so too.