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

[cm64]

@sueli428

@DBSAR

Correct. The LT1 runs the cells in Parallel, and keeps the cells all at the same voltage. I have had the same old, beat-up laptop pulls in the V1 Prototype now for 3 years, and not charged that lantern since last October. All the cells are at the same 3.71 volts now that i tested. The Production LT1 does not have thermal regulation, as it does not need it. the LEDs are at the head, while the driver and cells separated from them by the globe/shade. Also the output/amp draw of the LT1 is regulated and much lower than a hot-rod flashlight like the Q8, and even with all chips enabled, running at maximum output it stays below 70 degrees Celsius on the head/heat sink, while the driver & battery tube body remains below 35 degrees average. The LT1 being a lantern, it is designed & tested to run continuously, non-stop, at full-throttle, for hours on end & stay at a safe temperature, and stay at a linear light output for many hours, unlike a high-output flashlight with turbo mode that steps down after a few seconds or minutes, or even a flashlight running on high mode that steps down after minutes due to its thermal control, the LT1 is designed to stay at its maximum output for a long period of time (hours) before stepping down when the batteries voltage reaches discharged level.

That is sweet! Just got my new charger and EVVA 3500mah protected button tops.

Really want one of those yellow bowl shade / diffusers. It will mostly be used like a lamp in my application. I made one of those silicone folding dog bowl ones, but I would prefer the fixed shade. I have a few bowls to experiment with. More diffusing than the silicone one though.

Now I need to make a base / stand. I have a design idea. I think aluminum with 4 legs. Going to screw in the base threaded hole. It will raise the lantern off the ground an inch or two for uneven surfaces. The legs will attach up higher than the bottom of the lantern for stability, so the bottom of the lantern will sit down in the mount and be much harder to tip over. I don’t mind if that makes the lantern a few inches taller, as I think that will light even better.

I had an idea of adjustable legs that can fold up the side of the lantern. But the hinge and legs would make the overall size larger when folded up for storing or carrying.

Found this on ebay …
https://www.ebay.com/itm/Mini-Gorillapod-Monopod-Flexible-Leg-Mini-Cute-octopus-Tripod-for-Camera-HolderN/192925563896

one of many mini flexible leg tripods on ebay. Looks like it will do what you want.

[Gj1 (Gj)]

I’ve been playing with my first LT1 for about a week, can’t find anything to complain about. Congrats to DBSAR for driving the project forward for years to a very successful conclusion, and all of the other participating members and to Sofirn for their great execution of the design. Those Sanyo ZL2 cells I mentioned earlier fit in my lantern without issue.

There is currently a flash sale going on at Liion Wholesale, of special interest for the LT1 is the LG MJ1 unprotected button top 10A 3500mAH cell for only $3.49 ea. U.S. and Canada only.

[mr_magoo]

Much gratitude goes out to everyone involved in making this lantern happen- I love it! Thanks DBSAR for designing such a nice lantern and pushing so hard to make it happen, and much respect to sofirn for working with blf so closely and making such a nice, well built end product.

I have been using my lanterns every single day whether it is in part of my as-yet-unfinished house, or out in my barn with the momma goats that are kidding right now in negative 4°f cold, serving as their night light from dusk till dawn and for when I’m in there assisting with births.

I have been looking for a lantern like this for a long time, and the fact is there was nothing I considered good enough to buy so I just used flashlights.

There will eventually be 10 purchased by me- for myself, and friends/ family.

The only thing it doesn’t do that I wish it did is to serve as a usb power bank.

[DBSAR]

[particleez]

-

[Helios_azimuth]

@Coscar

@Skylight

When will Sofirn finally give out colored versions of the BLF LT1?

…Sofrin told me that dark green would be available in the next batch (no ETA) and new codes would be issued when that occurs.

That is great news. This is a fantastic and useful lantern and dark green is my first choice. Only ordered one black waiting for it.

[Kame_Sennin]

@sueli428

So the difference in voltage between new 18650 cells I am installing in the LT1 should be no more than 1V or 0.1V ? )

0.1V

@sueli428

But using the ohm setting on the fluke 179, I get 19.71 M Ohms and the other is 19.73 M Ohms which seems really high. I thought it was only supposed to be in the 2 or 3 range. Maybe M Ohms needs to be converted to Ohms by moving the decimal point one to the left?

Internal resistance from batteries can NOT be measured with an multimeter ohm meter, no decimal point shift trick neither anything else , it just doesn't work at all.

Sorry no time to elaborate now ;)

[bulbed]

Its few days now, got hands on LT1.I definitely feel its best value for my money.
Thank you @DBSAR and other awesome folks who helped to put this fine product.

Does the LT1 produce color temperature of daylight?If I recall reading here,bridging only increase the lumens. This is what it PCB looks like currently and I have plans to bridge.

I have a GorillaPod (original flexible tripod) and its a perfect fit to the base plate screw hole,if anyone is wondering .I think the LT1 and tripod,would be perfect companion to my next camping trip.

[Coscar]

@Helios azimuth

@Coscar

@Skylight

When will Sofirn finally give out colored versions of the BLF LT1?

…Sofrin told me that dark green would be available in the next batch (no ETA) and new codes would be issued when that occurs.

That is great news. This is a fantastic and useful lantern and dark green is my first choice. Only ordered one black waiting for it.

fwiw… that was a couple months ago in a PM. Hopefully that is still the case. :disguised_face:

[particleez]

@Kame Sennin

@sueli428

So the difference in voltage between new 18650 cells I am installing in the LT1 should be no more than 1V or 0.1V ? )

0.1V

@sueli428

But using the ohm setting on the fluke 179, I get 19.71 M Ohms and the other is 19.73 M Ohms which seems really high. I thought it was only supposed to be in the 2 or 3 range. Maybe M Ohms needs to be converted to Ohms by moving the decimal point one to the left?

Internal resistance from batteries can NOT be measured with an multimeter ohm meter, no decimal point shift trick neither anything else , it just doesn’t work at all.

Sorry no time to elaborate now

Ok thanks.

The xtar VP4 plus dragon charger I got claims to be able to test internal resistance with the probes. Are you saying that can’t test that either?

So what test would show if a new battery is good or not? Continuity?
Would a continuity test work with a protected cell?

Took this question to rechargeable battery thread.

[sbslider]

@ sueli, I don’t know your charger, but on mine the display had voltage, then you change the display and it will have capacity, then change the display and it will have the cell resistance. You can’t use a meter to test a cell except for voltage (NOT CONTINUITY). No continuity test for a protected cell, or a not protected cell.

[DBSAR]

@bulbed

Its few days now, got hands on LT1.I definitely feel its best value for my money.
Thank you @DBSAR and other awesome folks who helped to put this fine product.

Does the LT1 produce color temperature of daylight?If I recall reading here,bridging only increase the lumens. This is what it PCB looks like currently and I have plans to bridge.

I have a GorillaPod (original flexible tripod) and its a perfect fit to the base plate screw hole,if anyone is wondering .I think the LT1 and tripod,would be perfect companion to my next camping trip.

Daylight has a range of color temperature, (with the sun emitting the near perfect 100 CRI at the equator at high-noon) the color temperature of daylight can vary a lot depending on the location you live, time of day, time of year, and weather conditions. High noon can be as high as 5700K, while sunset can be as low as 3800K. The LT1 can produce anywhere between 2700K up to 5000K with high CRI LEDs it uses. (depending on the tint setting you prefer.

[particleez]

@sbslider

@ sueli, I don’t know your charger, but on mine the display had voltage, then you change the display and it will have capacity, then change the display and it will have the cell resistance. You can’t use a meter to test a cell except for voltage (NOT CONTINUITY). No continuity test for a protected cell, or a not protected cell.

Okay, thanks.

My charger says it can test voltage and resistance. So it displays voltage first, then resistance. The resistance voltage test doesn’t seem to be consistent, or really work on these batteries.

I was just trying to test if the batteries I got were good or not before throwing them in the charger and running them.

[bakeshow]

Has anyone else run into this issue? I noticed some of my batteries were rattling in my second LT1 and it looks like the springs are super compressed.

[adirondackdestroyer]

I just checked mine, and they are all the exact same length. The cells are almost all completely level on top.
Looks like some of these have some quality control issues. I’d ask for a replacement bottom spring to be sent to you.

[Cpeng]

@bakeshow

It looks like the springs were burned when cells of different charge were put in the light. Lithium ion cells have low internal resistance so the current can be stratospheric when you short two cells of different voltage/state-of-charge together. All cells need to be at the same voltage, one way to do that is charge them all in the same charger before installing them. Once they are in the light they will all be kept balanced, that includes when you use the light’s charging circuit. I wouldn’t every separate them because because then you will have to make sure they are all balanced before reinstalling them.

[bakeshow]

@Cpeng

@bakeshow

It looks like the springs were burned when cells of different charge were put in the light. Lithium ion cells have low internal resistance so the current can be stratospheric when you short two cells of different voltage/state-of-charge together. All cells need to be at the same voltage, one way to do that is charge them all in the same charger before installing them. Once they are in the light they will all be kept balanced, that includes when you use the light’s charging circuit. I wouldn’t every separate them because because then you will have to make sure they are all balanced before reinstalling them.

That makes sense, but I used a matched set of cells all at 4.19V. Wonder if this could’ve happened in testing at the factory. Either way, I’ve reached out to Sofirn to see if they will send me a replacement or if I should initiate a return via Amazon.

[DBSAR]

@bakeshow

Has anyone else run into this issue? I noticed some of my batteries were rattling in my second LT1 and it looks like the springs are super compressed.

That is indeed very unusual. I remember another member posting of a similar issue with springs that looked like they got heated & collapsed (as if two batteries were installed upside down to short against the other two cells, possibly in testing)

[BVH]

@bakeshow

Has anyone else run into this issue? I noticed some of my batteries were rattling in my second LT1 and it looks like the springs are super compressed.

Maybe not related, but why do your 4 cells have what looks like spot weld remains on their positive ends?

[wolfstyle]

They are probably laptop pulls.