Sofirn BLF LT1 (updated)

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Sofirn BLF LT1 A2 (Anduril 2) specifications (NEW)

Brand/model	Sofirn BLF LT1 Anduril2
Category	Camping lantern
LED	Samsung LH351D
Lumens	800 lm
Beam intensity	N/A
Battery config.	1-4*18650
Onboard charging	USB-C
Material	Aluminum
Modes	Many (Anduril2)
Blinkies	Many (Anduril2)
Reflector	Diffused
Waterproof	IPX7
Review date	March 2022

Sofirn BLF LT1 specifications (OLD model)

Brand/model	Sofirn BLF LT1 v5
Category	camping lantern
LED	Samsung LH351D
Lumens	600 lm
Beam intensity	N/A
Battery config.	1-4*18650
Material	Aluminum
Modes	Multi(Anduril)
Blinkies	Multi(Anduril)
Reflector	Diffused
Waterproof	IPX7
Review date	April 2021

NEW: Sofirn has created several iterations of the BLF LT1 lantern. Not too long ago, I reviewed the Rev 5.0 (or “V5” as I may refer to it) version. They’re now back with another version which seems to be dubbed the “Anduril2” or simply “A2” version for short. The advertised changes are:

• Move to Anduril 2 (instead of Anduril 1 previously)
• Addition of power bank functionality

OLD: If you’ve spent any time around flashlight forums, you should be no stranger to Sofirn. They’ve been around for several years and have released many nice lights at very affordable prices. In addition to being known for their wallet-friendly flashlights, Sofirn is renowned for their community projects they’ve produced alongside members of the BLF community. These projects have ranged from the diminutive C01 and C01S to the large and powerful Q8 and SP36 soda-can style lights.

One such project started back in 2016 (yes, 5 years ago): BLF member DBSAR started playing around with the idea of taking a BLF Q8, cutting the top off, attaching a circular diffuser, and then relocating the MCPCB with LEDs down-firing at the top of the light to create a lantern. The idea caught on like wildfire, with the group-buy continuing to grow before finally being capped at 3000 units. Other well-respected BLF members such ToyKeeper (firmware), Lexel (driver design), and many others joined with Barry of Sofirn to bring the BLF LT1 to life. The first production units shipped in October of 2019, and several slightly updated versions were later released.

The driver has recently been upgraded to “Version 5” which includes USB-C to USB-C (USB PD) charging. There are also new anodizing colors. I happen to have the pleasure of reviewing a green sample.

Package quality.

The BLF LT1 arrived in a rather plain, but sturdy brown cardboard box. The LT1 was protected by a bubble wrap sleeve. In all, the box contained:

• Sofirn BLF LT1 (green)
• 4x Sofirn 3000 mAh 18650 button-top batteries
• Charging cable (USB-A to USB-C)
• Orange bumper ring
• Spare o-rings
• Spare USB port cover
• Spare button cover
• Manual (very extensive and thorough!)

NEW: The physical aspects of the Sofirn BLF LT1 remain the same: the body is machined identically.  There are still several anodizing options (black, orange, green, and desert tan).  All of the changes directly relate to the driver, both the electronics design as well as the firmware.
One noteworthy change is to aux LEDs.  Whereas the V5 and prior had an orange aux indicator LED, the new version has a green LED.  I don’t mind that too much, but green LEDs are much brighter than their orange counterparts at the same resistance.  By default, the aux LED is on high – I’d say it’s almost bright enough to read a book by.  Sofirn really should have increased the resistance.  That, or let me know that they were changing to green and I would have made the aux LED be in low mode by default.  I feel that low is plenty bright, but not too bright – also much lower standby current, 87 uA vs 1.5 mA

Being built around a soda-can style light with 4 batteries, the LT1 has a definite heft to it. It does feel very sturdy and well constructed. The bottom is perfectly flat, which is good considering this is designed to tail stand.

There is a metal bail handle at the top that can be used to hang the LT1 or be used to attach paracord, if desired. There are also two tripod mounting points, one on the very bottom of the light, and one on the side between the switch and the USB port. As far as switches go, there’s just the single side e-switch (which is back-lit). The USB cover is well sealed and reveals a USB-C port.

The body / battery tube of the BLF LT1 is nearly covered in knurling. It’s not very aggressive, but it provides sufficient grip.  There is an additional pattern cut into the body that provides additional traction. The manual states the anodizing is HA III. The green anodizing on my sample looks very nice. I’m not very picky about colors, but it’s great to have other options than the typical black. Desert Tan and Orange are other options, currently. These make for a great emergency flashlight or a camping lantern.

The unique BLF LT1 logo is laser-etched immediately below the switch. The bottom of the light also has the usual regulatory etchings (CE and ROHS) in addition to “Built by Sofirn, Designed by DBSAR” to recognize Dennis, who put so much work into making the LT1 a reality.

Overall, everything feels well put together and refined. The threads are smooth and square-cut. The batteries fit nicely in the tube and make good contact with the double springs at the bottom and the solid brass ring on the driver side.

According to Sofirn’s website, they provide a 2-year repair/replace warranty on their lights, not including accessories such as pocket clips or charging cables. Batteries are currently under a 1-year warranty.

The BLF LT1 has 8 LEDs, all of them are Samsung LH351D 90-CRI to provide great color rendering and great output (lumens). Half of the LEDs are a warm 2700K CCT, while the other 4 LEDs are 5000K. One of the many things that set the LT1 apart from other lanterns is having both of these CCTs available and allowing you to mix the two sets of LEDs to choose a CCT anywhere between 2700K and 5000K. This is enabled through a special configuration of Anduril that includes tint ramping.

The 8 LEDs are soldered to a single large MCPCB which is affixed to the lantern’s cap. The down-firing light is sent into a frosted, tapered diffuser tube that provides very even light distribution.

• Length: 176 mm / 6.9 inches
• Head diameter:  68 mm / 2.7 inches
• Body diameter:  50 mm / 2.0 inches

Weight: 

• With cells:  642 grams / 22.6 ounces
• Without cells:  458 grams / 16.2 ounces

Flashlight Size comparison

Green Lights, from left to right: Astrolux EC01, BLF LT1, Sofirn C01

Large Lights, from left to right: Astrolux FT03 Copper, BLF LT1, Convoy M21C-U

Lanterns, from left to right: junky hardware-store 3xAA lantern, BLF LT1

New vs Old LT1 (not many physical differences)

NEW: One of the biggest differences is the move from the original version of Anduril to Anduril 2, with its Simple UI as the default. This is a great change as Anduril 2’s Simple UI is pretty straight-foward to operate and is nearly impossible to accidentally get into any sort of config mode. That said, for the firmware enthusiasts out there, all of the fun, in-depth options still exist, and then some. A 10H action moves you into the Advance UI.

For folks that like flashing firmware updates (we’re a strange bunch, I know!), the LT1 made that quite easy as it accepted the unofficial BLF standard pogo pin flashing adapter. Sadly, with the board revision, Sofirn has removed those flashing pads. All is not lost, however, as the driver can easily be loosened with 2 screws and removed enough to be able flash it with a SOIC clip adapter without desoldering any wires or any other sort of rigmarole.

OLD LT1:

This is a different Anduril image than used with other flashlights. The LT1 arrives in Stepped mode with 5 levels. Because the output is fairly moderate, the top level is actually the maximum (100%) output. That is to say, there is no actual “Turbo” mode.

Below is text copied from another Anduril based flashlight.

From OFF:

• Single-click: ON
• Double click: High (Top of ramp, to get to Turbo, you need to do another double click)

Enter Special/Fun modes from OFF:

• 2 clicks + hold: Strobe modes
• 4 clicks: Lock Out mode
• 5 clicks: Momentary on
• 6 clicks: Muggle mode

From ON:

• Single-click: Off
• Double click: High (level 5 of 5)
• 3 clicks: change ramping mode.. Instead of a smooth increase, it has 6 little steps between Lowest and Max.
• 4 clicks: change to ramping configuration mode
• Press and hold: brightness ramps up.. release and press and hold again to ramp down.

INTERESTING, SPECIAL AND FUN MODES:

Please read the manual carefully to know how to access or customize these modes. Also see the firmware picture, above.

• Blinky Utility mode:
• Battery check
• Sunset Mode
• Beacon mode
• Temperature check

Strobe / Mood modes:

When in the strobes mode, double-click to rotate between them – all modes except party strobe are brightness, changed the same way as a normal ramp. In party strobe mode, ramping up and down will increase and decrease the frequency of the strobe, for incredible effects.

• Candle
• Bike flasher
• Party strobe
• Tactical Strobe
• Lightning mode
• Lockout mode (can’t use the light)
  • Lockout mode is available by clicking four times from off – while in lockout mode, click-and-hold will light up at bottom of the ramp, and a double-click-and-hold will light up somewhat brighter. This is to give you a way to quickly use the light if necessary, but if it activates in your pocket, it will only be at very low modes, and only for as long as the button is pressed. No more holes in pants!
• Momentary mode (signaling/ morse coding)
• Muggle mode: (safer for children)
• Configuration mode
• Ramp config mode

PWM

• PWM: like most Anduril lights, PWM is present but fast enough to not be noticeable.

Additional info: one thing worth noting about this driver is that the end-user can adjust the number AMC7135 current regulator chips that the driver uses. Each CCT (2700K and 5000K) channel has its own bank of 7 regulators. By default, 5 regulators are enabled for each channel (so 1.75 amps). If desired, you could remove the solder bridge (or 0 Ohm resistor) to disable regulators 4 and/or 5 on each channel, or you can bridge the 6 and/or 7 pads to enable more regulators for a max current of 2.45 amps. The factory setting of 5 regulators for 1.75 amps is a good balance.

NEW: One of the headline features of the updated LT1 is the addition of power bank functionality. Considering the LT1 is packing quite a bit of power (it can house 4x 18650 batteries), it can be handy to charge your phone or other electronic devices in a pinch. Sofirn advertises that the LT1 can charge devices with 5V @ 3A (15 watts). I used my USB tester to run a protocol check and the only reportedly supported protocol is the standard BC1.2 DCP 5V at 1.5A. To confirm this, I fully charged the LT1 and mostly discharged my Pixel 6. I connected them through my USB tester (Fnirsi FNB38) and saw it charge at 1.45 amps.

The BLF LT1 came as a kit with 4 Sofirn-branded button-top 3000 mAh 18650 batteries. Button top batteries are required.  Sofirn states that the maximum length of batteries is 70 mm. Since the batteries are run in parallel, in a pinch you can run the LT1 on anywhere between 1 and 4 batteries – don’t have to have all 4.

When charging, the indicator LED in the switch glows red. Upon completion, it changes to green. Dear manufacturers: please stop using red+green charging indicators.

One of the things that were upgraded recently on the BLF LT1 is the ability to now use USB-C to USB-C charging. More specifically, USB-PD (Power Delivery) chargers now work. Which I find great, as I’m migrating towards USB-PD for many of my devices (phones, laptops, etc).

Sofirn recommends a 5V/2A USB charger. Higher voltages up to 15 volts may be used as the charging system now uses a buck charger. I ran two charging tests: one at 5 volts and one at 9 volts using an 18W (5V/3A and 9V/2A) charger. When charging at 5 volts, it pulled 1.52 amps for 7.67 watts. When charging at 9 volts, it pulled 0.85 amps for 7.67 watts also. The charge time for both tests were 8 hours and 18 minutes. Ending voltage for the batteries was 4.19V.

NEW: upgraded to Anduril 2

Old: Anduril 1

For current measurements, an ANENG AN8008 multimeter was used.  Lux was measured by a UNI-T UT383 BT at 1 meter.  Runtime output was measured in a homemade lumen tube using a TSL2591 sensor.

NEW: The last change that I noticed affects the brightness of the lantern.  The LT1 design has 2 banks of current regulators, one for the 5000K LEDs and one for the 2700K LEDs.  Each bank consisted of 7 of the 7135 chips.  The original design had 5 of them in each bank connected by default (so max 1.75 amps per channel) with another 2 chips in each bank that could be enabled one-by-one via solder bridges on the driver for a potential of 2.45 amps per channel.  Or you could remove 2 factory-set bridges to decrease the output to 1.05 amps max per channel.  This flexible design has been thrown out the window.  Now, all 7 of the 7135 chips in each bank are enabled from the factory with no way of decreasing the number of enabled chips.  So if you really want to have lower low modes on your LT1, you’ll either need to buy an older LT1, desolder some of the 7135 chips, or perhaps create some fancy firmware that attempts to lower the brightness through PWM without making the PWM too slow.  I’m not a big fan of this particular change.

Updated Lumen measurements (for each mode)

Updated: As noted with the V5 testing, the lumen measurements are rough estimates as the lantern doesn’t exactly fit in my lumen tube.

New LT1 Anduril 2:

Mode	Amps at start	Specs	turn on	30 sec	10 minutes
Level 1 of 5	21 mA	–	8	8	–
Level 2 of 5	216 mA	–	78	77	–
Level 3 of 5	638 mA	–	253	245	240
Level 4 of 5	1.3 A	–	472	463	454
Level 5 of 5	2.4 A	800 lm	883	861	840

Updated Parasitic drain:

• 1.5 mA with default of aux LED on high
• 87 µA after setting aux LED to low

Updated Runtime graph

All of the runtimes are very flat and well regulated.  They’re brighter (and shorter running) than the modes of the V5 due to the increased current of having all 7 of the 7135 chips enabled.

OLD:

Amp measurement  + Lumens 

• Level 1: 15.4 mA / 5 lumens
• Level 2: 159 mA / 50 lumens
• Level 3: 489 mA / 156 lumens
• Level 4: 1.0 A / 319 lumens
• Level 5: 1.8 A / 571 lumens

Parasitic drain:

• Aux LED off: 38 uA
• Aux LED on Low: 97 uA
• Aux LED on High: 1.7 mA

Runtime graph (OLD)

The runtime graph of the LT1 looks a bit boring – and that’s a great thing! We see well-regulated output that didn’t change much at all until the batteries started running down and Low Voltage Protection began kicking in at 398 minutes (6 hours and 38 minutes). At 436 minutes (7 hours and 16 minutes), the LT1 was extremely dim and I stopped the test. The battery voltage was around 2.9 volts.

Lumen measurements (for each mode)

Getting good lumen measurements with the BLF LT1 was a bit tricky. Normally I would use my calibrated lumen tube with it’s good TSL2591 sensor to get readings. But with how the LT1 disburses light all around it (and none out the top), it doesn’t work well in a lumen tube. So… I went with an old BLF standby: the integrating bathroom. I needed something big enough to allow the light from the LT1 to fully spread out. Doing so, I came up with readings that seem to be in line with what other people have observed:

• Highest mode (5×7135) with 2700K: 420 lumens (at 0 & 30 sec)
• Highest mode (5×7135) with 5000K: 571 lumens (at 0 & 30 sec)
• Highest mode (5×7135) with 5000K: 562 lumens (at 10 minutes)

Throw numbers: 

It feels wrong to talk about the LT1 and “throw”. It’s made to not throw. That said, here are some measurements that were made from 1 meter away:

• 2700K: 54 cd = 15 meters / 16 yards
• 5000K: 73 cd = 17 meters / 19 yards

• LT1: camp site, warm white (2700K)
• LT1: camp site, neutral white (5000K)

Disclaimer: This flashlight was sent to me for review at no cost by Sofirn. I have not been paid to review, nor have I been holding back on problems or defects.