Did you try using a USB-C to Apple Lightning cable when charging your iPhone? I suppose the iPhone‘s chipset expects a special code in order to start charging. When you use a type A to type C adapter in between, the chipset communication between LT1 and iPhone might become corrupted.
I don’t have one, but will see if I can borrow one to test. I did wonder about that, but also felt like if it normally charges from USB-A it isn’t expecting a whole lot. This is a topic I’m totally clueless on though.
Well, sh*t… As it turns out, a DIY modification of the indicator LED color scheme might be a bit more difficult than I anticipated:
I was hoping the reassignment of LEDs would be possible by simply swapping some of the wires connecting the driver (BLF-LT1-A2) and switch PCBs. Or at worst case, swapping the SMD LEDs themselves on the switch PCB assembly. Plus if necessary, replacing the current limiting resistors. The datasheet of the powerbank IC also supported this theory.
Boy, was I wrong, though…
Here is the reverse-engineered schematic of the switch assy and its connections to the driver PCB:
The circled numbers denote the identically numbered wires between the driver and switch PCB
As you can see, the LEDs controlled by the PB controller are connected antiparallel to each other and driven sort of “differentially”. Which makes wire swapping not feasible.
What’s even worse, the blue and amber LEDs Sofirn chose are in fact not separate components. They are part of the same 0606-size duo-LED. (The green one on the other hand, is a plain 0603 single-color led.)
The different package sizes and the fact that the blue and amber LEDs are integrated means swapping the existing LEDs around is also out of the question.
At this point, the “easiest” option left is to buy new LEDs, 2 duo and 2 single with the colors you want, and replace the current ones with them. If you’re determined enough to do that, and you intend to use a hot air soldering iron for the removal part, be careful not to melt the tact switch (wall it off with Kapton tape or aluminium foil), as the clearances are awfully tiny here… If I were to go ahead with this mod, I think I’d just use 2 normal irons (or an SMD tweezer iron) instead, just to be safe.
Here are some examples of applicable replacements for the duo led:
https://uk.farnell.com/kingbright/kptb-1615surkcgkc/led-red-green-80-50mcd-smd/dp/2426238
https://uk.farnell.com/kingbright/kptb-1615esgc/led-red-green-7-12mcd-smd/dp/2426236
https://uk.farnell.com/lumex/sml-lx0606igc-tr/led-1-5mm-x-1-2mm-red-green-smd/dp/1789153
https://uk.farnell.com/dialight/598-8410-207cf/led-red-green-65-59mcd-633-570nm/dp/3548426
https://uk.farnell.com/w/search?led-colour=red-green&packaging=cuttape&st=150066
If you live in luckier parts of the world where the really big distributors (Digikey, Mouser, etc.) do not have absolutely ridiculous shipping fees, you might find more options.
Unfortunately, I am pretty much stuck with Farnell, and in the applicable package size, I found only the handful of LEDs above in their catalog.
Fun fact: the indicator LED driver configuration utilized in the LT1 is not documented at all in the IP5310 datasheet. Its 2-LED mode is supposed to drive the LEDs in a basic single ended configuration, with no series (current limiting) resistors, since the IP5310 itself has integrated current regulators:
So either Sofirn decided to use the driver “in a creative way”, or it is an intended, but undocumented feature of the IP5310, borrowed from its bigger brothers which support differential LED drive natively.
What I still cannot wrap my head around though is why the engineer at Sofirn chose to implement the LED drive this way in the first place. The usual argument for the differential approach is to save an extra wire (no dedicated GND needed).
Bun the LT1’s switch PCB needs a GND wire anyway for the switch and the green LED, so in our case the number of wires connecting the 2 PCBs were not reduced… It is also strange they went for the blue-and-amber duo LEDs, which are rather exotic, and I imagine more difficult and expensive to source, instead of the more ubiquitous red-and-green ones combined with standalone amber LEDs. I guess we’ll never know…
Anyway, happy modding! 
Some extra details about the driver (BLF-LT1-A2) :
- Some photos
- 7 x AMC7135s per channel, all hardwired
- The programming/debug pads are directly wired to the Tiny’s pins 1: pin1, 2: pin2, etc.
- The power supply of the Tiny looks like this:
Glancing at the previous driver PCB’s, I’d say it is probably unchanged.
- A simple, but effective pFET-based reverse battery polatiry protection is implemented. Nice!
- The circuit built around the IP5310 pretty much coincides with its official reference schematic (except for the differential indicator LED drive), so it should be fine.
- As already determined, the IP5310’s dsplay engine is used in 2-LED mode. Which is a clever choice, since, as opposed to the higher LED number display modes, it does not utilize the embedded Coulomb counter / fuel-gauge algorithm for triggering the low-battery warning. It uses a simple voltage comparison with a predefined threshold (2.95V, typ.) instead. This is good news, because, the fuel-gauge is guaranteed to “get lost” when other consumers keep sipping power directly from the battery terminals (in our case the white power LEDs), since it has no way to measure that and incorporate it into its calculation.
- The IP5310 is used in the following configuration:
(Overall completely reasonable, IMO)
| Pin | Connected resistor | Corresponding config setting |
| 1 | 1k to Vcc | 2-LED display mode |
| 3 | N.C. | 4.20V Nominal charging voltage |
| 4 | N.C. | fuel gauge config - irrelevant for the LT1 |
| 5 | 10k to GND | Battery internal resistance 45mR |
| 6 | 50k8 to GND | Dummy NTC |
Production quality of the driver PCB assembly (BLF-LT1-A2) in my LT1:
Overall, not bad at all:
- the visible solder joints look nice,
- the inductor (the only heavy component) is glued down,
- the wires they used are of good quality: thick but still flexible,
- the wires are not glued down => if you accidentally break them, they can be easily desoldered,
- the hand-soldered joints (of the wires) are robust.
- There is noticeable “solder balling” on the board, though. I.e. free-standing little balls of solder stuck in the flux residue on the PCB. At least two of them should be noticeable in the photos linked in my prev. post. I counted at least 5 of them, total. Fortunately they were not large enough to be a real risk of short circuit if they break loose by heat / vibration etc. Your mileage may vary though… This is a well known and studied production defect with reflow soldering, usually caused by expired or low quality solder paste or a suboptimal reflow temperature profile.
Funny, I usually rate wires good as high strand count - flexible, while cheaper wires are low strand count - stiffer. Dunno if the cost reflects that though...
Lot of suspect lower quality wires in the lights are low strand count, but the Turnigy brand and what Hank uses/sells is high strand count, also 200C rated. Cheaper wires seem to be 150C rated.
I know the insulation layer can vary in thickness as well, which can get confusing. For our use we want usually moderate thickness - not too thick to fit the holes and for clearance, but not too thin to cut or tear easily.
I would think the LT1 driver circuit and I/O pins assignments/etc. is open source? See post #736 here. Ohh - don't see the LT1 driver though on DEL's OSHPark list.
Maybe DBSAR knows if the LT1 circuit design is available publicly? Sometimes these relationships we have with the manufacturers has some limits, other times it's just lack of asking, or communications, etc.
The LT1 circuity has not really been displayed as a full diagram, but it is laid out as “layers” in the design of the driver for the LT1 in the the team meetings & chats, DEL, Toykeeper, Lexel, Bary, Sofirn, etc. of all who were more involved into the design of the LT1’s driver & firmware as for the MCPCB design, firmware, etc. based on the LT1’s modes & plans from the original prototypes & testings. Maybe we can put together a schematic & diagram of the “brains” of the LT1. I am ok with that being made public, but it really depends on the driver & firmware developers of the team, along with Sofirn if they are ok with releasing it.
Hi does this have Anduril 2.0? I just received mine. Clicking and hold 10c doesn’t change anything.
My link Aliexpress
My USB-C to Lightning cable doesn’t work with it.
Hi,
Have you had any updates?
I was trying to get more information about this light before I bought it and I wasn’t sure what you were saying lately, other than the situation is not clear to you either.
Did Sofirn make any changes in the led power supply that make the LT1 hotter? If so that’s a bit sad.
You mentioned the button leds, are there any plans to change that in the near future?
Does anyone have the footprint of the new flashing pads so I can try to make a connector to flash the firmware?
In general, should I take advantage of the small promotions to get it on the Sofirn site or wait for a new version? And if I order on Sofirn’s website, will I get the latest version or is it random?
Thanks for the information if you have any.
Have a nice day.
I ended buying a second LT1 on Aliexpress because I liked the idea of having a USB-C compliant chip and being able to use it as a powerbank in a pinch.
Did some comparisons and made some pictures for you:
I have a USB-C Protocol and power analyzer, will test the new LT1 board later today.
Does anyone know how to differentiate which of the ground (black) cables from the new (with power bank) driver connects to the warm and which to the cold LEDs?
Since the manual PDF file on google is offline, who knows where to find it now?
https://drive.google.com/drive/folders/1HIFCFcBus5XRjKMfgkjAR7nH1R62qp_5
Here’s an Anduril 2 graphic for the LT1:
If you are looking for the original LT1 manual (and other Sofirn manuals), please check here:
I had to redeploy my files on Google Drive because the old links did not work anymore.
If you are looking for the manual of the new LT1 with Andúril 2, I need to ask you for patience. It is work in progress already. I do have a manual that Sofirn made on their own and that is currently being supplied with the new LT1 version. But there is a lot of wrong or missing information in it, it’s not worth putting it onto the sharepoint.
These versions are known:
|version|date|post URL|
|lexel 4.3|19.08.2020|https://budgetlightforum.com/t/-/38215/11664\|
|lexel 5.0|16.12.2020|https://budgetlightforum.com/t/-/38215/11042\|
|lexel 5.1|11.07.2021|https://budgetlightforum.com/t/-/38215/11580\|
|Sofirn 1.0|11.07.2021|https://budgetlightforum.com/t/-/38215/11578\|
|Sofirn A2|11.07.2021|https://budgetlightforum.com/t/-/38215/11595\|
Any more known board versions out there?
And what are the differences?
In a nutshell, is Sofirn A2 the “best” release of the LT1 thus far?
Also, if someone is OK with Anduril 1 and doesn’t intend to leverage the power bank feature, is it preferable to get the earlier version? I’m really concerned about all of these intermediary board changes. And I’m sure with the way things are, you can’t request a sub-version, only the LT1 Anduril-1 or LT2 Anduril-2.
My Sofirn 1.0 LT1 has limited power bank capabilities. It doesn’t work with Apple USB-C to Lightning while the Wurkkos HD20 works with the cable. It’s also on Anduril 1 without version check.
Good to know this. Has anyone found that Sofirn A2 avoids that problem and a USB-C to Apple Lightning will charge an Apple device (iPod, iPad, iPhone, etc.)?
Where is the cheapest to get a Sofirn lt1 these days? I don’t mind getting version 1 without the power bank.
Cheapest would be from Sofirn store. But you have to consider shipping as well:
$52 - https://www.sofirnlight.com/products/brown-lt1-lantern-anduril1-usb-rechargeable-flashlight-without-power-bank-function
$58 - 22.9€ |Sofirn BLF LT1 8 * LH351D Camping Licht Mehrere Bedienung Verfahren Super Helle Taschenlampe Variable Farbe 2700K zu 5000K|LED-Taschenlampen| - AliExpress
$70 - https://www.ebay.com/itm/384253590938
$93 - Amazon.com
Thank you. Ordered the brown one in Sofirn website.