Micro Lantern build

Lynx_Arc

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Not 20/120 lumens, but 20/120mA. Per the Optisolis datasheet, the output is approximately 8 lumens and 42 lumens. However, the high setting appears much brighter than a light rated at 45 lumens. By contrast, my original battery drainers are in the 8+ lumen range (depending on LED), but will light a room sufficient to navigate. That is using a "dead" cell which continues to put out a declining light until it drops below the 0.6V range. The lanterns will not go as low on high, but do a really good job of draining cells on the low setting.


The lanterns were purpose built for someone living off grid, using only solar to charge cells. They have AA NiMH and Li-Ion cells. The emphasis is on extended runtime with a respectable brightness. As with anything, there has to be a compromise. I visually selected the high and low settings after testing a lot of current sense resistors in circuit. In testing, I gauged whether I could read or do other tasks efficiently. The 200mA setting was only marginally brighter than the 120mA setting. But, it made the LEDs heat up in short order, as the heatsinking ability of the copper surface area is limited.

That is what I get from reading too fast, lol. 8 and 40+ lumens are still respectable outputs 8 for area lighting and 40 should be enough to work and read by as we used to do more with 15-30 incan lumens. I've personally found around 10 lumens a good enough amount of light for a room I recently purchased some cheap 3AA LED tap lights from WM that use a chip LED warm white color and are rated at 10 lumens and with diffused light they well light up a room in the dark. 40 lumens is pretty darn bright for a small lantern. 200ma is getting pretty high current for depleted cells for sure. I'm not as much interested in something like this to drain batteries but rather a way to use any battery at hand for light the lithium ion support is what makes this like a Popeil's pocket lanterman :p
 

xxo

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45 lumens is a good amount of light for a lantern. I have been using lanterns a lot lately since I have been working on 3D printed lantern kits (for Maglites mostly, so far). Even through a 3D printed diffuser, my 55 lumen Nite-Ized Fulton mX991 puts out enough light to eat a meal by, read a book by or play a board game by during a power outage. Even my ML25 on it's 29 lumen low mode does a good job for these things once your eyes adjust to the dark a bit.

I think many lanterns on the market are too bright, making them hard on the eyes through all of the glare caused by too many lumens being run through poorly designed diffusers and burning up too much power from their batteries.
 

RamBull

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Why not just get the BLF LT1? It might be a good backup or primary lantern.

I know they’re trying to make a mini version which will also probably be just as amazing.

Nevertheless, good luck with you micro lantern build. Seems like hell of project to commit time but if it brings you happiness, more power to you. =]
 

archimedes

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I am sure I'm missing something but why not get .....

Why not just get ....

I'm guessing if OP wanted those types of suggestions, this thread would have been posted in the "Recommend me a light" subforum ?

CPF also celebrates builders and modders, and the "Homemade and Modified" subforum is where our discussion is focused more on these challenges and successes.

There may well be any number of commercial lanterns available, but out of courtesy to OP, his own work-in-progress build thread is probably not the best place for that.
 

marcdilnutt

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I'm guessing if OP wanted those types of suggestions, this thread would have been posted in the "Recommend me a light" subforum ?

CPF also celebrates builders and modders, and the "Homemade and Modified" subforum is where our discussion is focused more on these challenges and successes.

There may well be any number of commercial lanterns available, but out of courtesy to OP, his own work-in-progress build thread is probably not the best place for that.
Well said

Sent from my [null] using Tapatalk
 

MLD03c

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Hello, I am pretty new to this world, but really like what you are doing here. What are you using to allow for the wide range of voltage here? Is it some sort of super small regulator? If I need to be pointed elsewhere I totally understand. Trying to build my own lantern, but would like to power off of 4 aa or aaa cells (6 volts) and am trying to find the best way to do that. THANK YOU,

Lee
 

808vudoo

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Hi D, such beautiful and thoughtful work as always. Would love to purchase one when they are ready for public sale.

Big Aloha, D
 

Bimmerboy

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I'll put in my interest for one as well. I'd actually like one without a diffuser, and 4000K Optisolis would be perfect for me.
 

datiLED

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Hello, I am pretty new to this world, but really like what you are doing here. What are you using to allow for the wide range of voltage here? Is it some sort of super small regulator? If I need to be pointed elsewhere I totally understand. Trying to build my own lantern, but would like to power off of 4 aa or aaa cells (6 volts) and am trying to find the best way to do that. THANK YOU,

Lee
Hi Lee,

This can only handle up to 5V per the datasheet, but should ideally be kept to 4.2V, the maximum for a Li-Ion cell.

If you are looking for a circuit for a 6V input, use the filter at Mouser or other electronic site and plug in your desired parameters. I start with IC packages that I can solder by hand or hot air. I then input my desired input voltage, output voltage and current. It gives you a list of parts that match. I then look at the datasheets to see if the application circuits are something that I can build. Once that is decided, I order parts, design a PCB and begin prototyping. I usually etch a few PCBs at home with PnP Blue and ferric chloride. If things go well, I have OSH Park make me some PCBs.

For 6V, you would probably be looking for a low dropout regulator. Use the parameters that I mentioned above, and you should be on a good path. FWIW, the circuit that I am using is directly from the IC datasheet. I just added a switch to select between two different current sense resistors.
 

radellaf

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PCB layouts for switchers (and hot air soldering) aren't always my favorite thing to do, so if/when these go on sale I'd definitely be up for one or two, depending what they'll be selling for. As much as any utility, I'd enjoy a light where I can look at the not-in-a-case battery it is running off.


I've been using 4pcb to fab boards at my job, and their free layout software. I know I'll have to switch to eagle or kicad one of these days, but it has got the job done. I try to put as many little 1206 LEDs on the boards as I can. Looks pretty and can help with debugging things.
 

Dave_H

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Interesting. Ability to run cell down to 0.6v means there is pretty much nothing left although I have gone down further; not a big deal at that point.

Cell run-down for me includes solar garden lights using boost circuit which can get down to 0.8v-0.9v or a bit lower. I sometimes take 3-4 of these and run down further in series in a small AA LED lantern, at low intensity of course; fine for night-light.

I've been pondering schemes to run down 9v batteries which come out of smoke detectors but usually still 7-8v, lots still left. That would use a buck circuit for single LED for high efficiency. Alternatively it could be just a couple of white LEDs in series with resistor, or linear current regulator with low dropout.

I am not off-grid but sometimes pretend to be, when running down my supply of free (occasionally leaking) alkalines.

I agree that Li-ion cell charging can be done but adds complexity and cost. If external charging works, stick to it.

Dave
 

Dave_H

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I did some digging around for specific vendors/parts for either step-up or step- down cases. Part used here looks like a low-voltage switching step-up regulator typically used in backlighting, am I correct? There are a number of these taking in typically 2.5v to 5.5v (some higher) and can drive up to 5-6 white LEDs in series. Ones which can operate below 1v are less common except some solar garden lighting which usually only run with 1-2 1.25v cells.

There are a number of Chinese vendors for these chips but also lots of more recognizable names such TI, Microchip, ON Semi, Monolithic Power Systems, Diodes Inc. etc.

For reduced brightness/current, looks like this boost setup could drive two LEDs instead of three. If cell voltage is low it might even drive one LED. Because the output is constant-current one of LEDs could even be shorted out with no damage.

If I were prototyping it would depend on device being available in a leaded package e.g. SOT as opposed to leadless which is becoming common. Some people are equipped/comfortable with solder paste, ovens or hot-air guns etc. for the latter; depends on the end goal I guess, whether it will become "productized".

Dave
 

808vudoo

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Aloha D,

the micro lanterns arrived to the islands and they are absolutely fantastic. I was able to use them with various cells, in different states of charge, and they put out a nice amount of quality light…and those magnet set-ups got some good grip too.

Thoughtful and excellent builds as always…another happy camper in paradise!

Big Alohas and much thanks brother, D
 
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