BLF LT1 Mini Review – At Long Last

Contents

The Boring Stuff

This light has been in development for over two years, but has seen many delays due to the pandemic. It’s finally here! Sofirn (the manufacturer) sent me this light in exchange for an honest review. Here is the official product page where you can use code M5GFBN6T to get 20% off. I don’t earn any points or commission or anything off that, it’s just a code Sofirn gave me to share with you. Below are the official specs.

What comes in the box?

The box is typical from Sofirn. It’s plain, thinner cardboard with a small foam pad on the bottom and a bubblewrap sleeve to protect the light. The following items are included in the box:

  • The light itself
  • Battery (inside the light)
  • USB A-to-C charging cable
  • Lanyard
  • Two spare O-Rings

Notably, a user manual was missing from my sample and someone else on BLF had the same issue. Sofirn assures me that will be corrected in the future. Fortunately, LT1 Mini runs Anduril 2 so any UI-related questions can be answered by the official Anduril 2 Manual from Toykeeper.

Design & Construction

Just like the original LT1, the design resembles a normal flashlight with a diffuser stuck onto the bezel. It doesn’t have the typical compact camping lantern look like LT1S does, but it’s very narrow so it will fit places that other lanterns cannot, like an EDC bag or an ultralight backpack. Unlike most flashlights with a diffuser on top, this diffuser is rigid and has an aluminum cap and bail on top. The tailcap flares out just a bit to provide more stability.

Build quality is good, as I’ve come to expect from Sofirn. They’re particularly good at making smooth threads and this is no exception. They’re anodized, well lubricated, and reversible. The tube has a battery direction indicator on it so I don’t recommend reversing it to avoid confusion. There’s a beefy spring in the tailcap held in a cavity by its own tension. I can’t find any complaints with the build quality.

Size & Measurements

Sofirn LT1S | Sofirn/BLF LT1 Mini | Sofirn/BLF LT1

Fireflies E07x Pro | Convoy S12 | Sofirn/BLF LT1 Mini | Convoy C8+ | Noctigon KR1

MeasurementMeasured (mm)
Maximum Head Diameter45.0
Length154
Switch Diameter11.0
Switch Proudness2.1
MCPCB Size29
Body Tube Diameter (internal) 21.9
Body Tube Diameter (maximum)26.0
Body Tube Diameter (mode)26.0
Body Tube Length72.3
Tailcap Diameter31.0
Tailcap Length17.3
Driver Diameter24
USB Port Width12.1
USB Port Depth2.9
Included Battery Length70.6
Included Battery Diameter21.5

Weight without battery: 108g
Weight with included battery: 180g
Weight with Molicel P26A 18650 battery: 154g

About the size & weight: it’s very small and very light. I almost thought they forgot to send a battery when I picked it up. It’s a little over half the weight of LT1S despite using the same battery. LT1 Mini is markedly smaller than LT1S as well. LT1S needs a bag or something for transport, but you can toss LT1 Mini in a jacket pocket or even a roomy pants pocket. It’s light enough you could even hang it from a neck lanyard (or shirt button) and be perfectly comfortable.

User Interface

LT1 Mini was designed by a bunch of flashlight nerds on Budget Light Forum (hence “BLF”), so naturally it includes the nerdiest firmware: Anduril 2. It’s a highly-configurable and feature-rich UI that’s not for the faint of heart, but it’s a joy to use if you know it well. I’m not remotely prepared to do a whole UI breakdown, so I’ll just direct you to the official Anduril 2 Manual which has a UI table at the bottom. With that said, here are a few of my favorite features. Most of these are highly configurable or optional, so if you don’t like one, you can probably disable or change it!

  • Momentary Turbo
  • Adjustable Stepped Modes
  • Manual Mode Memory option
  • Shortcuts to & from Moonlight, Turbo, and High
  • Battery voltage readout
  • The best LVP behavior in the industry

It’s worth noting that mine came with firmware version 2021-08-29-0621, so it’s missing some of the latest features like instant-switching and 200% turbo. Mine is a pre-production sample so it has a weird flashing pad layout, but the full production LT1 Minis will use an Attiny1616 MCU with the requisite 3-pin flashing pad layout for (relatively) easy firmware updates.

It’s also worth noting that the voltage check was reading 0.2V high out of the box, which is weird. Fortunately, Anduril 2 features voltage calibration so I was able to adjust it.

Modes, Brightness, Throw, & Tint

Disclaimer: I cannot measure lumens for a lantern so all lumen measurements are estimates based on the assumption that Turbo meets the advertised brightness. A candela measurement was taken at 1 meter with an Opple Light Master III on the highest brightness, and other candela figures were calculated relative to that. CCT & DUV data was taken for each mode directly next to the diffuser with the Opple Light Master and Waveform DUV Calculator. Runtime tests were performed with the Ceilingbounce app on my smartphone. All of these tests were performed with a fully charged included battery unless otherwise specified. None of this is professional equipment, so take all of these measurements with a grain of salt.

Level Lumens (@ Turn-On, Estimated)Candela (@ Turn-On)Throw (meters)CCTDUV
Turbo (150)305291125900.0008
High (120)18518825900.0009
Medium (80)828626000.0009
Low (40)212325900.0011
Moonlight (1)1Too low to measureToo low to measureToo low to measureToo low to measure
Warmest Setting
Level Lumens (@ Turn-On, Estimated)Candela (@ Turn-On)Throw (meters)CCTDUV
Turbo (150)31033114590-0.0020
High (120)1912094590-0.0019
Medium (80)85964580-0.0017
Low (40)21234550-0.0018
Moonlight (1)1Too low to measureToo low to measureToo low to measureToo low to measure
Coolest Setting

Why those modes? Anduril 2 has 150 levels, so doing measurements and tests for each mode is virtually impossible. I’ve got this light set up how I like it with 5 levels. Bottom of ramp is level 1 and top of ramp is level 120. I’ve set up the stepped ramp with 4 steps so, with turbo added, I get the 5 modes I like.

Mode Spacing / Ramp Speed: Mode spacing is good. There are no oddly small or large jumps. Ramp speed is good too, being a consistent speed at all brightness levels. This doesn’t ship with the absolute latest version of Anduril 2 so you cannot slow down the ramp speed.

How does it compare to the official specs? I am unable to measure Lumens out of a lantern, but when I removed the lantern diffuser and measured, I got 420 lumens maximum. After losses from the diffuser, the official spec of 310 lumens seems perfectly reasonable to me.

Bonus Spectrometer Readings: I had the opportunity to borrow a Sekonic spectrometer briefly, so here are readings from LT1 Mini on Turbo.

Runtime & Regulation

Performance: The runtimes look great. There’s no thermal throttling which is nice. Turbo lasts for 4 hours before low voltage stepdowns. High lasts for a little over 6 hours. Medium lasts for a little over 15 hours. There’s plenty more runtime after low voltage stepdowns on all modes too in case you need emergency lighting to find another battery or something.

Regulation: Is pretty great. Battery voltage does not affect brightness until the very end when the battery nearly empty. No separate regulation tests are necessary because there is no thermal regulation to skew the results, so we can use the runtime graphs as regulation tests.

Thermal regulation: There is no thermal regulation present, but it’s not needed because all modes are thermally sustainable. The light never gets warm enough to warrant thermal regulation.

LVP: Is present and works extremely well. Anduril steps down brightness in big, obvious steps when the cell gets low to warn users of low battery and to extend battery life. Then, eventually, when the battery is basically empty it will shut completely off.

Driver & Regulation

LT1S appears to have a glued-in driver, which is a shame, but par for the course from Sofirn. Mine is a pre-production sample so it has a weird flashing pad layout, but the full production version uses an ATTiny1616 MCU with a 3-pin flashing pad layout that’s quickly becomming common across several Sofirn & wurkkos models.

I reached out to Sofirn and asked about the driver’s construction, and they said it uses 7135 chips just like the original LT1. Based on the output, my guess is there are two 7135 chips per channel.

PWM: No PWM is visible to my eyes on my review sample. It’s audible on Medium and High modes if I listen for it. It’s visible to my phone camera with the exposure set really low. I also got a full production sample after posting this review and it does not have any audible PWM on any level. I don’t know if they made changes to the driver or if there’s just some variance between samples.

Parasitic Drain: 400μa with switch LED’s on high. 170μa with the switch LED’s on low. 120μa with switch LED’s off. None of those measurements are concerningly high, and even with the switch LED’s on high it would take well over a year to drain the included battery.

Emitter & Beam

Just like the original LT1, LT1 Mini uses Samsung LH351D LED’s in two different color temperatures: 2700K & 5000K. These are a good LED choice as they’re both high CRI and high efficiency. I do wish they went a little warmer for candle mode, and a little cooler on the high end just for fun. The LED’s sit on an MCPCB on an integrated shelf in the head just like any normal flashlight, so reflows should be easy. I imagine Nichia 519A’s will be a popular reflow option since they have even better color rendering, and dedomed 2700K’s get very warm for candle mode.

The diffuser takes a fair amount of force to unscrew the first time, but after that it can be done by hand. Inside there’s a orange-peel reflective dome to help spread the light outward. I noticed the “HOT” warning symbol was on top of the diffuser like it is on the full size LT1, but LT1 Mini has the emitters in the head so that’s what gets warm (but not hot), not the top of the diffuser. The light can be used as a tint-ramping mule without the diffuser. It would be great if Sofirn were to release a clear bezel one could buy separately to protect the LED’s when using LT1 Mini as a mule flashlight. Perhaps it could be sold as a bundle with a magnetic tailcap & flashing afapter!

LT1 Mini Warmest | LT1 Warmest
LT1 Mini Warmest | LT1S Warmest
LT1 Mini Coolest | LT1 Coolest
LT1 Mini Coolest | LT1S Coolest

Switch

The switch is backlit, tactile, audible, and located on the side of the light. It’s exactly the same switch used on the full size LT1, right down to the T on the boot. That T harkens back to the BLF Q8 project, where a manufacturer called “Thorfire” (later Sofirn) agreed to make the light. LT1 was a spin off of that project so they continued to use the same switch boot. There’s a retaining ring around the boot so it should be removable with some snap ring pliers.

The switch is backlit in a couple different colors. There is orange backlighting that’s controlled by Anduril so you can change it to one of four modes: off, low, high, or blinking. It’s bright enough, but not as bright as the original orange LT1 button. There are also much brighter blue backlighting that indicates charging status.

Carry & Ergonomics

LT1S is a little weird ergonomically. There’s no obvious way to hold it like there is with a traditional flashlight or larger lantern with a handle. You can hold the body tube, but that feels a little weird. You can’t hold it by your side like that or it won’t illuminate what’s in front of you. You can’t hold it out in front of you like that or it’ll cause glare because half of it is shining back at your face. Holding it by the bail works well, but I can only get one finger through the bail so it doesn’t feel as secure as a proper handle. It’s way lighter than LT1 though, which is great because LT1 is uncomfortable to carry by the bail due to weight.

There’s a lanyard included in the box that attaches to the tailcap, but that’s it. No pocket clip or holster or anything. LT1 Mini fits nicely in a Convoy C8+ holster, and if you do want a pocket clip, I imagine LT1 Mini’s head would fit on most of Sofirn/Wurkkos’s 21700 bodies (TS21, SP35, HD20). You can also hang LT1 Mini from a shirt button if you’re so inclined.

This really should have come with a magnetic tailcap. I tested the Wurkkos HD20 Tailcap but it won’t fit. I purchased one of these magnets and it works great. All that’s needed for installation is to stretch the spring a bit with some pliers, then slide the magnet inside the spring. It’s strong enough to hold LT1 Mini reliably on vertical surfaces.

A strong, factory magnetic tailcap has been missing from all three LT1 versions so far, and I sincerely hope Sofirn will start to offer them in the future. It would have been trivial to change the tailcap design slightly and use a triangle-base spring to hold a magnet in place like Skilhunt H04 RC’s tailcap. I asked Sofirn if they have any plans on making a magnetic tailcap for LT1 Mini in the future, but they said no.

Batteries & Charging

LT1S includes a 5000mah, unprotected, flat top 21700 cell. It will not fit protected 21700’s, but some unprotected button tops might work. Any variety of 18650 will work too (protected or unprotected, flat top or button top). This light draws relatively little current so you needn’t worry about the discharge rating of your battery.

LT1 Mini Battery | LT1S Battery

I noticed this included battery differs from the one included with LT1S. You can see that I tested & labeled both with their specs. The capacities are drastically different (by 1000mah!) and the positive contacts are different as well, despite these having the exact same wrap. I don’t know that every LT1 Mini or LT1S will come with these exact cells, but I was initially under the impression that they were identical so I thought it was worth mentioning.

Charging is facilitated by a USB-C port on the head. It’s covered by one of Sofirn’s excellent rubber flaps, the same one used on LT1, LT1S, Q8 Pro, etc. It’s very secure and it’s probably the best designed port cover I’ve seen. I have zero concerns about its water resistance.

Charging worked just fine from A-to-C and C-to-C cables. Charging took 3 hours. It works when charging, but only with a battery connected, and there’s an audible whine. It also works as a powerbank too, which is cool. It stopped charging another device at 3.33V.

When charging (itself or another device), the switch LED’s will glow bright blue. Flashling blue switch LED’s indicate charging or powerbank function. Constant blue means it’s fully charged. I prefer the red-means-charging and green-means-full indicators on my full size LT1 Rev 5. The single-color charging indicator can be ambiguous if you merely glance at it.

Competition

Here are some lights in the same class and how they compare.

Sofirn BLF LT1: four 18650’s instead of one 21700, much larger, much heavier, brighter, runs much longer, tripod mounts

Sofirn LT1S: Shorter, fatter, brighter, much more stable, directional function, red function, great charging indicators, same battery

Emisar D4V2 with a Greenmikey Diffuser: Available with several driver options (including Boost and Dual-Channel), huge variety of emitter options, aux LED’s, magnetic tailcap, 18650 instead of 21700 battery, works as a flashlight too, optional short 18350 tube

Thrunite TS1: smaller, lighter, cheaper, doesn’t get as bright, less battery capacity, battery itself works as a powerbank with charging indicators, magnetic tailcap, magnetic caribiner, multi-tip USB cable included, USB-C rechargeable 18650

This section is not comprehensive. If I didn’t include a particular light here, it doesn’t mean it’s bad or doesn’t deserve to be here. I simply cannot list every possible competitor.

Conclusion

LT1 Mini is a fabulous addition to the LT1 line and offers compelling portability not found in either of the two larger models. It’s ideal for tossing in an ultralight camping backpack, EDC bag, or even a jacket or pants pocket.

Thanks to the users of BLF for designing this light and to Sofirn for sending me this sample for review!

5 thoughts on “BLF LT1 Mini Review – At Long Last

  1. Great review! Any tips on how to change the 2700k to 5000k?
    I also got a different driver then the light in this review, strange.

    1. To change between 2700K and 5000K, you click the button 3x from on and hold the last click. It will smoothly adjust the color temperature and you can release the button when you reach your desired color temperature.

      If you got a different driver that’s very intriguing. Do you have any photos you could share? Perhaps upload them to Imgur and then reply with a link to them?

    2. Wow! Thank you for the great photos! The 3-pin flashing pad layout on the driver leads me to believe it may be using a different controller, specifically an ATTiny 1616. That may make firmware updates easier for some people, but I’m curious what firmware version they’re using now. May I include your driver photo in my review? Can you do a version check and let me know what yours says?

      1. You can use the photo’s in your review not a problem. How can I do the version check? I have loads of flashlights but I’m a noob with electronics 🙂

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