*BLF LT1 Lantern Project) (updated Nov,17,2020)

I see an opportunity for an intrepid party to create an easy flashing adapter jig for the later driver boards with the non-standard pad layout.

It’s something that I imagine a 3D printer would be well suited for.

There’s a big ole hole formed by the contact ring that would neatly accommodate a disc or short cylinder with contact pins, directly connected to the flashing apparatus. The two mounting screws/holes make for easy indexing/reference points.

Or, with short jumpers to a standard connector, serve as an adapter plate of sorts. Emisar’s reflashing kit looks like it uses a standard header connection to the pin end, so unplug that from the ribbon cable, plug in the LT1 adapter plate, and voila, Bob’s your uncle.

The screw holes could also make an alternative “bridge”-like design feasible, without having to use additional material to solely for locating purposes within the hole with a disc.

Depending on when the firmware is loaded in the production process, I wouldn’t be surprised if the factory might already employ something like this…

Flashing flashlight firmware is a niche within a niche, so it’s not an idea that will form the basis of a business empire, but it would be a neat community project.

Anyone up for it?

To be honest, it is very easy to get to the chip on the LT1, you just need to unscrew 2 screws and the driver pops out, there is no glue and no need to desolder anything.

It literally takes less than a minute.

Once you have access to the chip you can just use a standard SOIC clip to flash it.

Length of tripod screw? 1/4 in.–20 x ?

I upgraded the firmware on my LT1.

Long story short, the firmware installed successfully but my light isn’t functioning properly at the moment because the switch is broken.


I just took measurements of my LT1 from the very first batch.

I’m not sure if these dimensions have remained consistent.

bottom tripod hole: 5.64mm or approx 0.22”

side tripod hole: 7.83mm or approx 0.30”

Cant find anywhere does LT1 has low voltage protection? I am asking because somehow my LT1 stopped working and when I checked batteries they were totally empty I dont remember exact voltage but it was close to 0V. I have newest driver from Sofirn with powerbank function.

Yes, it has low voltage protection, so most of us use unprotected batteries.

Question: I just received my BLFLT1 with the A2 driver board and green LED’s. I’m trying to use the power bank function without any success. It will not charge my original LT1 or my SP36 BLF. When connected to my S21 Ultra it charges at 300 mA which is not enough to keep the screen on and hold its own let alone charge the phone. My USB DMM reports 4.75 volts at .294 amps when attempting to charge my phone. I tried every USB C to USB C cable I own and see the same. Several are higher end Anker cables. Any info appreciated.

it does have low-voltage protection.

Oof, blue would imho indeed be a serious mismatch for the intended use. It is a lantern and this makes it more important to use a colour that is suitable for a nightlight, camping, etc. Much more important than with normal flashlights. Blue wakes you up and personally I don’t want that in the same room where we sleep. With amber it can just stand on a bedstand or next to your pillow in a tent, basically in your face and you won’t be bothered by it.

And since this is the original LT1 thread, I just wanted to give a big thank you to DBSAR (and Sofirn) for creating this thing! The LT1 is absolutely THE BEST latern I’ve ever owned and my son and I use it every night as a bedtime story light. Good moments :slight_smile:

Great to hear another happy LT1 owner :smiley:

Add me to the happy LT1 owner list. Love it and use it all of the time. The links earlier in the thread for the shade and base are appreciated as well. The accessories make the lantern more versatile.

While it was myself who got the project started, I have an awesome team and contributors who spent time, and worked to make it a reality, including, ToyKeeper, SIGShooter, Barry0892, DEL, The Miller, Phlogiston, Lexel, sbslider, BlueSwordM, bmengineer, Lux-Perpetua and amishbill. these all deserve the equal credit on this project, ( and future projects we work on.

February,08,2022

( also updated in the main OP Topic post.)

An update on the LT1, and other projects including the LT1M (mini)

  • The pandemic has slowed things down quite a bit, including my big move, lifes-change, etc. But i am still dedicated to new progress on this BLF project with Sofirn for future models, advancements, etc.

While it may have been myself who got the project started a few years back, I do not deserve all the credit in this what so ever… I could not have done this alone at all… And with an awesome team and contributors who spent time and worked to make it a reality, including, ToyKeeper, SIGShooter, Barry0892, DEL, The Miller, Phlogiston, Lexel, sbslider, BlueSwordM, bmengineer, Lux-Perpetua and amishbill.

These all deserve the equal credit on this project, (and future projects we work on.) i wis those who enjoyed this venture and a happy customer of the Sofirn BLF LT1, give them all a great thanks of appreciation. You all are amazing, and valued in this project so much! Along with the family of the BLF community, SB working so much to make this community great, I again thank you all from my heart. – Dennis / DBSARlight

I used this lantern a bit last summer, then left it somewhere on a table.
Today I try to turn it on and won’t turn on. So I take out the batteries and see that 3 of them are discharged downto 2.3V and one is at 3.7V.
I’m not sure if this is normal or not, but I thought I should post about it.
It seems that it self-discharges quite a lot when not in use, and not evenly.

Are you using button tops, or flat tops with solder blob?

Flat top batteries.

button tops will fix your issue, flat tops don’t make a good enough connection

That is very unusual, as all four of the cells are held in parallel, thus they can only discharge or charge all at the same rate. There must be some issue with the cells not contacting the top ring, (as flat-top cells would cause that and not recommended.) even then the cells should never self-discharge at that rate unevenly unless the cells are defective.

A friend had a similar situation but he had 1 battery below 2v with the other 3 above 3.8v. He also hadn’t used it in over a year and like Kat’s it wouldn’t turn on.

It’s interesting that his light as well as Kat’s wouldn’t turn on with at least 1 battery > 3.7v given that the LT only needs 1 battery to run. Unless as you say that they weren’t making contact with the ring for some reason.

If I get a chance I’ll look at his light and batteries. Could be that he’s using flat-tops where contact with the ring can be hit-or-miss depending on the brand.

He was using old laptop batteries which could account for the 1 cell reading so low. As I understand it drain from the switch is minimal and shouldn’t draw much from even a single battery over the course of a year.