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

Has this been answered yet? It looks like the programming pad layout is similar but I’m not sure how that works.

They are not the same.

Contacted Sofirn via PM, got a code within hours and order placed!

Thanks Sofirn for being so responsive and helpful with my questions. :slight_smile:

So finally I got some lull so I was able to make the mod to the LT1 so that it charges from USB-C to USB-C.

It is doable but it isn’t easy

Cable works in both orientations. I have tested with only one AC adapter but it the one that obeys the USB spec so it should work with any that does so too.

I have charged from 3.9V to completion and there doesn’t appear to be any issues, couple of minutes before the green light the cells were about 4.172V

I have taken one picture but frankly this isn’t the best of my work. And the pictures don’t show much

If anyone is interested I can put more detailed description of what I did and what to do.

Very interested in seeing more. Mine hasn’t arrived yet, but I plan to do it when it does.

I received an initial single use code for a lantern only, but due to the problems with ordering, by the time that it was available again via Amazon, the code had expired. I responded to Sofirn and let them know and was told:

“Thank you for enjoy the lantern and your patience. The next batch will be avaliable around 15-20 days later. And we will pre-order it around 5-7 days. And then we will send another code to you to order more. Thanks again.”

I’m not in a rush at all, my concern is that they’re under the assumption that I already ordered one in the initial batch, which I wasn’t able to despite having ~ 8 reserved in the first 500, and I didn’t receive a code for Lantern + batteries. I’m not mad or even annoyed, and I fully understand the logistical nightmare a project like this entails and am perfectly happy to wait as long as needed.

My only concerns are that people like me receive all the lanterns they signed up for, and it appears that some, like myself weren’t able to order but Sofirn is under the impression they have and still others never received codes in the first place.

Again, a big thank you to all involved in this project, I’m extremely excited.

Barry, thank you for the response. I tried ordering, but the amazon link was no good due to all the problems that were occurring with the first batch. I tried ordering, but wasn’t able, and by the time the amazon link was live (I admittedly didn’t check daily), the code had expired. I’m fine with ordering one at a time, but I’d like to get at least a single unit in this next batch. I appreciate all the work that everyone has put into this and am very patient and in no rush.

As a preface, this requires decent equipment, decent skill, attention to detail and ultimately might result in your lantern being damaged beyond repair from either inappropriate use of the equipment or incorrect execution.
Even though I performed the mod successfully I give you no warranties. If you blow a hole in your PCB or one of the ICs you did it yourself.

So to mod your LT1 to charge from C to C cable you will need a following:

  • Mod wire. Thinner the better. Best would a magnet or enameled wire of 40 awg or above. Like this I have used a scrapped parts of a litz wire. If you are looking for some on the cheap then if you take apart any relay, small electric motors the chances are that you will find an enameled magnet wire that will work.
  • 0402 or 0603 resistors like this we need 5.1kOhms +/-20% so technically any value between 4.1k and 6.1k would work. Not sure where you could source those on the easy. If buying from anywhere buy at least 10. They are super small so if you even think about sneezing around them they will disappear. They should be cheap enough, probably pay more for shipping as compared to the hardware.
  • A soldering iron. Preferably something direct heating and has decent tip on it. Standard chisel won’t work. I worked with one like this this
  • Tweezers that are angled something similar like this . Any other tweezer will do as long as you can grab a 0402 comfortably but the curved ones will make your life easier. Preferably another pair of tweezers
  • other soldering equipment solder, flux, wick, wire cutters, IPA, possibly brush etc
  • RTV preferably clear but a red one will do.

Once everything is gathered you can start.
You need to lay the driver flat and secure it. The wires should be long enough to allow you to pull it out, and secure so that it doesn’t move (you can use double sided tape to whatever it will be laying on). Kinda like this (borrowed from djozz from here) Any movement during soldering will be your enemy.
Note here. When I did mine I didn’t remove any of the wires going to the main leds but you can. If you do so then you will have much better access to what you want to do it. However I didn’t feel like doing so since there is a lot of wires and most of them are black.
Here is the data sheet for the USB C connector used in the LT1. What are you are looking to do is connect CC, pins A5 and B5 to A1, A12, B1, B12 through the resistor. Here is pointed out what is what on the actual picture USB-C .
Find a decent spot for the resistor, I initially put them more or less like this .
With the resistor position set, cut you enamel wire so that you don’t have deal with the whole bunch of it.
Strip the ends of the wire using your soldering iron. What I do with enamel wire I put bunch of solder on the tip of the soldering iron and then stick how much I want to strip and leave it there for couple of seconds.
Take the resistor and tin the ends of them. Similarly put a bit of solder on the tip and then touch to the end of the resistor so a bit sticks.

Now comes the hard part. Apply as much flux as you are comfortable with to the connector pin. Put as much solder as you can on the pins that you will be using. If you get some pins bridged it’s not the end of the world. Use the wick to clean it up.

Once you have the pins tinned, it is pretty much solder everything in place. What I aimed to do is the following. What you can do with the magnet wire is that once it is solder in place you can “snap it off” by keeping it taught (but not pulling strongly otherwise you might lift a pad) and move it back and forth until it comes off. Since the resistors are not attached to the board you will have to support them using another pair of tweezers or something pointy.

After about 45min of swearing and wishing that your hands were smaller and listen to your parents and didn’t sit so close to the TV you will end up with something like this . Even though it is ugly it is type of situation that if it is stupid then it works.
Clean with IPA and brush gently.
Visually inspect to make sure that there are no visual shorts etc.
If everything looks good then proceed to testing.
What I did is, I plugged in the usb-c charger to the wall, gave it couple of Mississippi, unplugged from the wall, then plugged in into the LT1 without batteries. Since the USB-C provide significant power they generally have enough energy stored in the input and output caps so that they can hold up the its internal and LT1 circuitry for few seconds. By doing this you limit the incident energy that is available so if there is anything wrong, there might be a puff of smoke but you shouldn’t destroy the connector or the board.
If everything is alright then you will get a flash, that the LT1 has power, and the green LED that the batteries are fully charged.
Once you have everything tested and confirmed that it works, apply the RTV to the area to ensure that the mod doesn’t get damaged physically. What I did is gave a squirt of the RTV and gently pressed into the board, tried not to smear it around.

Hope that helps you guys. If you have any questions then let me know, will do my best to answer them.

$12 bucks on Amazon, no soldering required, use cable that comes with lantern. Problem solved

If it works for you that is great.

All of the things that I travel with use usb-c.

So now if I want to take the the LT1 then that and a cable is another thing that I can’t forget.

Also I would much rather spend $12 on beer than another charger.

Enjoy the beer!

mlodyulek thank you very much!

Why are you dismissing his work? He was generous enough to share what he did to get usb-c to usb-c charging working.

mlodyulek - very insightful, thanks.

Great job mlodyulek!

Thanks for the detailed guide with pics! There are plenty of us who like to fix things ourselves even if just for the challenge.

Someone needs to buy the 10,000 resistors for $12 and throw two at a time in envelopes and mail for a 50 cent stamp to DYIers in the USA for a few bucks per pack!

thats a large % of posts nowadays… taking the piss out of someone.
I’m glad he posted it, I got a buddy who does that stuff in his sleep… now to find resistors and mod - because BLF is about Budgets and modding !

Don’t give me ideas. I just got a 100 pack of standard resistors, and will have 100 each of two different size (bigger for easier manipulation) SMD resistors.

Sounds like just enough for the 100 lanterns you’re buying :slight_smile:

THANK YOU, Barry and Lan Lee! This sort of communication is precisely what potential buyers would want to hear. So long as everyone knows what’s going on and that they have someone to ask when they have questions, then Sofirn is doing a great job.

Will the resistor mod prevent charging using a 12v input?