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

The classic mistake with the Q8 (reported more than one time) is sticking in one of the 4 batteries reversed, and there is nothing that the circuitry can do about batteries directly shorting against each other this way. With some bad smells, one or more of the bottom springs will collapse and likely break electrical contact and save you from battery destruction, but you will have solder new springs after that.

permanent LED trimmer added and changed to my 2x2 LKED board with WW LEDs

The plan was to have 4 or 5 enabled and the remaining left un-soldered for modders.

Please put me on the list for one light! Thank you to the team for all the amazing hard work on this one-of-a-kind lantern :smiley:

Sample has arrived! First impressions are good. :+1: First thing i did notice is the head section, ( globe/shade and head) is somewhat larger than the prototype builds, though the measurements were sent based on the V2 (the one on the right in the below photo) the sample factory build is a little larger. I am ok with that, though its larger size makes it a little less compact as the prototypes, it still is smaller than most more expensive LED lanterns on the market.

- As Lexel & Toykeeper found the sample has all the 7135 chips enabled, and no doubt it is much brighter with more output than the V1 & V2 builds. (will have less run time on maximum modes, but i will test it using either 3000mah or 3500mah matching cells in comparison to the prototypes all on maximum modes, and test amp draws.

- I really like the satin anodizing finish, it makes the Sample LT1 look really good and high quality. I can see a few alterations needed from my first views. One being a slight change to the head to allow a paracord to be attached in addition/or in place of the bail handle. I do like the metal bail handle too, and there are ways of attaching a paracord in addition. (will explain in the upcoming video review.)
Some other changes that will be needed is change the green switch glow LEDs to a very warm white (or preferable 2000K flame yellow) The thread anodizing needs to be a bit thicker, as unthreading it for a mechanical lock out on my sample don’t work unless its threaded almost off completely. As Lexel & Toykeeper mentioned some refinements in the firmware adjustments will be good too. the globe lens seems to be a heavier frosting than the prototypes, so that may block a bit of the light transfer output, (I will test it in the light sphere with the lens & with out to compare the loss-percentage to the prototypes with & without. I do really like the custom coin-type center bolt head, it looks very professional & clean, much better than using a generic screw bolt for the head.

overall i am very impressed on the sample, and the alterations & changes are more of just some refinements than anything major. it looks very quality built, much better than any other retail lantern i have tested & seen before.

- now on to beginning the long tests over the next week or so. :sunglasses:

Excellent news!

I’m glad your sample arrived safely and I’m sure you’ll enjoy all of the testing you’ve got planned.

I like the idea of warm switch LEDs.

Team LT1 should be very proud. Keep up the good work, everyone! :+1:

It is nice to see them next to each other :slight_smile:

I agree that the shorter shade on the V2 looks better. Sofirn may be still in a design stage that the shade can be shortened a bit? You can always ask, and a shorter lantern is an advantage.

About the switch-leds: I have done a quite comprehensive search for all kinds of micro-SMD leds (0403, 0603, 0805) for use in lighted switches and I can report that a good warm white is not on the open market, although Sofirn as it is based in China may find sources that I can not access. The warmest are 2700K and are a low CRI ugly tint. There is one led from Nichia that is 2700K 80CRI and nice tint (Nichia NSSLT02A, I have a few of those) but that one is fragile, with a thick silicone cover that is easy to knock off, you do not want it near a moving switch and cap. Also a phosfor-converted amber would be nice but I have never found those in the small leds category either, the smallest is the PC-amber Nichia E17A, a bit too luxurious for a switch led.
Instead you may want to settle for red or orange, with red being a more efficient led (may not be so relevant in this application with 4 big batteries, runtime is forever anyway).

I wonder if Yuji could be convinced to make a tiny high CRI very warm white emitter for us. With over 1400 on the list, and two emitters per switch, we’re already close to 3000pcs. That seems like a respectable order size to me, but it depends on whether they already have tooling and equipment to make such small emitters and whether they are even interested. If they can make 5mm leaded package LEDs, they should be able to make tiny SMDs too, right?

I’m speculating, but I don’t think Yuji makes LED packages themselves. My impression is their specialty is the phosphor, and they contract with other LED manufacturers to have products made with their phosphors. That would be favorable to being able to make “small” batches of specialty LED’s. However, “small” in the semi-conductor industry is probably tens or hundreds of thousands of pieces.

I did my own quick look for options. It’s probably redundant with searches djozz has already made, but just in case, hopefully this link pulls up the properly filtered results. Are any of these potentially suitable?

Digikey search for white 0605, 0705, 0803, 0805 packages

I too like the shorter shade of V2 in order to keep it more compact. But either way is fine.

In relation to the 4-5 or 7 AMCs, would it be possible to have an option of ordering with the 7? I’d personally prefer the ability to go a bit brighter, while still having access to lower outputs for better runtime. What about an option of 8 AMCs? Makes it symmetrical for 2 chips per LED (or possibly 1 per LED during tint mixing). Just a thought. If not, where is a good place to get bare chips? I’m not very good at soldering, but would probably try it in order to get more output. Also, would a standard soldering gun work, or is something special needed?

Thanks for your work on this team. I’m pretty excited for it.

At the moment the test-sample LT1 has all 7-chips (7 for each tint channel) enabled. I will be testing the run times & amps soon. As for adding chips, 7135s are readily available, and can “stack” them if your experienced with soldering and small electronic components. (but in this case pushing the current past 7 or 8 chips will increase heat, and in a lantern where continuous running is used it could be a problem with overheating the head.

Thanks for the response DBSAR. And I just looked up Texas_Ace’s test of the LH351Ds and wow, they can throw out some good light. At 7 chips, it looks to be putting out around 1,200 lumens at the LEDs, so with globe losses, it should still be plenty bright. I wouldn’t need to go higher. I was just hoping for ~1,000 lumens as the brightest mode, and it looks like it can do that already…awesome. :slight_smile:

Dont’ forget we are aiming for 4 chips per channel.

That means 8x7135 total.

No! 4 total
The plan is to build all lanterns with all 7 equipped
How many are active by default has to be chosen

I don’t know if TK plan to have a sort of 4000K all AMCs turbo planned or not

Please put me down for one more (total 2)

Thank you.

What is the height difference between the V2 and the sample ? Doesn’t seem way more than about 1 cm.

No, I wasn’t planning to have a 4000K turbo mode. It can’t sustain that much heat.

For anyone who missed the details earlier, the lantern has 14 of the 7135 chips, with 7 attached to each set of LEDs. So it can make about 2.45A of warm white and 2.45A of cool white. For the middle tints, it tries to maintain a steady power level while changing the amount of power which goes to each channel. But exactly in the middle, it could also have a 4.9A turbo mode.

In the current prototype, middle tints actually decrease in power because the mixing formula doesn’t account for the non-linear PWM response curve. But I plan to fix that in firmware so it’ll maintain pretty close to a steady power level regardless of tint.

I think the plan is to set the default power limit to 1.4A or 1.75A. This increases the runtime without making it visibly much dimmer, and it also makes the light safer thermally. But those who want more power could simply touch a soldering iron to a couple spots on the battery side of the driver, and it would enable more of the 7135 chips. Creating a solder bridge like this is really quick and easy to do.

That sounds awesome and super easy TK. And thanks for the re-explanation of what’s going on with that. I apparently missed that earlier. :+1:

Maybe this will be the precursor to a BLF light bulb with tint ramping

Looks great, put me down for 1.

I’m only worried about the diffusing material. Looks too white instead of a frosted clear material (Like sticking DC fix to a clear lens). White semi translucid diffusers can degrade over time and turn the tint yellowish/greenish.