The 4th Annual BLF / O-L Contest; MtnDon's Entry, Hand Made Class

I must thank DBSAR for inspiration. It was his lantern project with the downfire LED that helped me formulate this plan. The vessel, well that was purely from my own weird thoughts.

I do find the phosphor dome illumination to be pleasant. The dome does not have that annoying pin prick effect that many commercially made lanterns have. I do prefer lights in the 4500 –5000 K range over the warmer tones. I’m different that way. So this suits me fine. The phosphors are available in some warmer temperatures but in smaller cone / elliptical shapes. This dome was easy to fit over a standard LED star. A cone shaped phosphor with a diameter of around 15 mm and smaller would make for a more difficult mount. Just another challenge though!

I am thinking about incorporating a micro LED voltmeter, but space is a bit tight inside the mug. … thinking cap is still on…. I think it would be cool to be able to monitor the battery voltage without having to access the cells. Maybe a momentary contact switch to activate for the reading? But I also don’t want to make it more difficult to access the cells. Easy changing of the cells was a prime goal of mine. And switches mean perforations and more wires……

Just use a driver with a batt check feature as one of the modes.

I love your unusual design.

By micro LED Voltmeter, are you thinking of one of these ? Perhaps you could simply set it up so that the battery voltage is always displayed when the light is on. The listing claims it uses less than 30ma, but I will measure one tonight. It seems like you could mortise the meter into the battery block without too much trouble.

I had and lost a couple of these meters, ordered a 10 pack to replace them, and promptly found the lost ones once the new ones came in. PM me your address and I’ll send you one if you would like.

Yes that is the meter type. It may be possible to mortise one into the cell block. Would be cool. With a very low draw having it only on with the light on would likely be hardly noticeable. Thanks for the offer.

Looks great, Don. Did you leave any room in the mug for some beer? :wink:

That would be different to the normal water cooled. :stuck_out_tongue:

:laughing: They make double walled mugs. The space between the two walls is supposed to be insulation. I had the crazy idea that it would be cool to use that space to hold the beverage and have the light works inside as I have done. Some kind of a “sippy cup” mouthpiece feature for drinking from would need to be implemented / invented. :person_facepalming:

I decided to do some run time tests. The first one was perhaps ill planned. Running at level 4, approximately a 25% power setting of around 350 mA, according to theory. The run began with all 4 cells at 4.1 volts. Twelve (12) hours later the voltage, after a short rest, was reading 4.03 volts. I’m thinking I should have used a single cell to spped it up, although drawing 4x the current from a single cell may not correlate exactly to the lower draw on multiple cells. I don’t know; I am guessing and extrapolating from lead acid experience.

Anyhow I stopped that test and am recharging. At that rate level 4 should last a few days. I may run this again when I don’t feel so impatient.

My second bout will be on level 5, approximately 50% power, or 700 mA. Four cells or a single? Have yet to decide.

I should also do some “tailcap” current readings to see how close the actual flow is to the theoretical programmed levels. I’ll do that after the 50% run time test.

Wow, a good lantern !Nice mod! :+1:

Just completed a run time test using a single 30Q, 3000 mAh cell and running the light on level 5, 50% power = 700 mA.

The cell had been recently charged. Voltage reading at the beginning was 4.20 volts.

After 3.25 hours the light was shut off, I went to bed. In the AM the cell read 3.71 volts.

After a total run time today of 5.5 hours the cell voltage read 3.22 volts after being given a 30 minute rest.

I ran it another 30 minutes, for a total 6 hours and shut off. The immediate voltage reading was 3.07. 15 minutes later the voltage had recovered to 3.10.

I ran it another hour, actually 58 minutes and picked it up and headed to the shop with it still on. On the way the lamp blinked three times. As I reached the workbench it began to blink. The voltage read 3.01 volts.

The Nanjg specs state that at 2.9 to 3 volts this is exactly what the driver should make the light do.

For the last hour run the brightness level appeared to be decreasing. Bumping to level 6 did still increase brightness. It did not appear to be as bright as before, but since I have no meter that is a purely subjective statement. I do have a meter on order though. :slight_smile:

Anyhow at the sixth hour the brightness can still be called servicable. If we multiply the 6 hours by 4 (cells) I believe it is safe to say that we have about 24 hours os useful service from a full set of four cells, when run on level 5. Good enough for me I’d say.

I forgot to note that on level 5, the heat sink ran about 20 degrees F higher than the ambient air temperature, whereas on level 4 it ran about 8 degrees F warmer.

Everybody (here in US and Canada) have a great Labor Day weekend. Stay safe but have fun.

That’s a pint o’ light. :+1:

Well I am embarassed. :blush: I was showing the light to my son on the weekend. Suddenly I became aware that there only appeared to be three 7135 chips in place on the driver. It can be difficult to see clearly around the upper area where the mug walls turn inward and then upward again. Sure enough, close inspection found only three 7135’s. Photos before 8/27 show 4 chips! 8/27 was about when I disassebled major components as I changed some design elements. I must have lost one 7135 as I heated the upper plate to change the driver to the new plate. Or lost it during the reassembly. Too much heat and not enough attention.

I did think the run times I had obtained were impressive! Rightly so considering the light has been running at 3/4 of what I thought it was. But all to the good; 3 x 7135 do seem to be quite adequate for the lights purpose.

:slight_smile:

Doh! :person_facepalming: At least it wasn’t the mcu that fell off.

I would have noticed that a bit earlier though. :person_facepalming: :smiley:

So this morning I went and measured with meter… I should have done that before and I would have realized something was amiss.
Top row is the asked for percents for the levels, 2nd row the calculated values based on 3 x 7135 = 1.05 amps. 3rd row is measured value
2% …6% …15% …25% …50% …100%
21 mA … 64 mA … 158 mA … 262 mA … 525 mA … 1050 mA
19 mA … 59 mA … 145 mA …255 mA … 501 mA … 1031 mA
Now if I could make some lumens sense…

I don’t think a regular integrating sphere will be able to measure it with another degree of confidence given the radial output and complete lack of any “beam” so there wouldn’t be other similar lights to calibrate from. Best comparison might be measuring some standard lights with diffusion caps for relative numbers but even then the actual lumen output measured could be way off. I think “best guess” will be as close as anything.

A while ago I tried to envision a way to make a chandelier bulb by illuminating a hollow Chrystal shaped diffuser but this would be an ideal way to do that or make illuminated costume jewelry. Somebody get rich and remember me. :money_mouth_face:

I was thinking it was a problem; more a subjective thing than objective with the equipment available.

I should note that all along the planning stage I was thinking 4 x 7135’s mightbe unneeded. DBSAR is quite happy with only 2 or 3 - 7135’s on his SRK lantern project.

What’s necessary really depends on what you’re doing. I’d want more light in the OR than in my bedroom and more light for fine solder work than for cooking. For a lantern to while away the hours of a storm reading it may or may not need more. Chances are you’d be fine just sitting close enough to it.