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

not set in stone, but everyone seems to want the 2700K as the warm-end of the tint ramp. I only had the chance to test the 351B series of 3000K and 351D of 4000K, ( i have nto been able to get any 5000K to test or 2700K to test.

Not rusting USB. My fault. I left the link out. The item is some different length stainless steel zip locks. Some creative use could provide a strong non-rusting. handle or something. Just thought they were interesting.

The USB cables they have can get pretty long. Prices are good.

Please don’t forget about radiator on the top! 900 is too much for that small part with small surface area.

I thought about that. I haven’t had the time to add one or two more 7135s to the V2 prototype to test it on high for heat levels yet, but right now with four chips (1.4 amps) its gets hot, but not so hot to burn a hand. ( roughly 50 degrees C with my temp tester after a hour running. Maybe i may ask Toykeeper to see if its possible to program the firmware to step down a mode after 30 minutes if it got to hot if set at 1.75 amps on high.
Because the top only holds the LED star, the driver or cells are isolated from the heat. I have thought about adding fins to the head, but not sure how it will look. (i may have a look at that too)

God I can’t wait for this lantern, those specs look absolutely amazing!

I’d suggest using thermal regulation, but that’s physically not doable on this light.

However, if it’s an issue, one thing we can do is set the default ceiling values to a sane level… and then only turbo will be hotter. In practice, what that looks like is having a regular set of modes, plus one. So if it has modes 1, 2, 3, 4, and 5 in the normal range, turbo would only be 6 on a visual scale. It doesn’t look much brighter, even if there’s a significant temperature difference.

I thought that firmware have thermal control, isn’t it?
Thermal sensor should be it top part.
On the other hand it is not good for lamp if it change output from every gust of wind.

I think the best decision is one direction temperature control

The firmware has thermal regulation, but it won’t work in the lantern. The sensor is built into the MCU, which is in the middle section of the light. So it cannot sense LED temperature. They are too far apart.

An external sensor doesn’t work either, because the MCU has no pins left.

Maybe we could still use this internal sensor to automatically adjust the ceiling based on the ambiant temperature, but I think that a lamp this size shouldn’t have problems cooling a thousand lumens with a few cooling fins added. If that isn’t sufficient we could maybe try to use the center bolt as a heatpipe to the lower section and use it for cooling as well.

I also thought about this.
Central bolt made of steel it is bad heatpipe. But we can add copper pipe around the bolt. This also increase crushing strength of construction.

For example pipe d=10mm h=50mm thicknesses 2mm take 10W(definitely more than thermal power of lamp) with dt=20C.

Non-aholics run stuff wide open all the time .They have no concept of runtime and have the brighter is better mentality .Pretty sure this light was never intended on becoming a lumen monster .

Runtime/UI /tint and cri are my top concerns .

If you need more light ...buy two

:+1:

you mean you don’t want a lantern that so bright it gives you a tan at 0000hrs? why the heck not???

:wink: :wink: :wink: :wink: :wink: :wink: :wink: :wink: :wink: :wink: :wink:

I think the goal is to build the lantern so it has enough thermal mass and surface area for its power level, so it physically cannot overheat during normal use. A heat pipe from the top to the middle might help increase the thermal capacity, if necessary. But we don’t know yet if it is necessary. Maybe if it has a maximum power level around 1.5A, it might not need any more changes.

I don’t really have a good solution for heat on this light, aside from just trying it to see what works. Perhaps some vertical fins on the top section could help increase surface area in a manner which encourages air to move even without a breeze. For example, when hanging inside a closed tent.

When used outside, it should be safer since the air is always moving at least a little.

So far in my tests at 1.4 amps at the cells on maximum mode with the four LH351D LEDs the top of the lantern has not got to hot even after a hour running on max. ( no higher than 45 ~ 50 degrees) i doubt it still wouldn’t be a concern even with 1.6 amps considering the top is a large solid mass of aluminum.

This is something I do not need but really want… I’m not sure how I’m going to explain this one to the misses but please put me down for one!

It’s an emergency light for power outages - (for her safety and convenience) :wink:

I am increasingly mystified at what people are expecting from a useful practical efficient lantern.

The very concept of having a FET, and a “turbo” mode is utterly ridiculous. I hope I have mis-understood and that was just a naive poster spouting nonsense.

Higher power and better heatsinking could perhaps have been achieved by upward-firing LEDs from the body, the same as most other LED lanterns do it, but this is different. It fires down from the top. And it is a good decision I think. It ought to be capable of easily supporting four LEDs, if driven sensibly at their most efficient points. Not over-driven to ludicrous levels.

Which has been a key design decision, based on practical experimentation. And the correct way to go IMO for a practical lantern.

Don’t listen to the “max power, push the LEDs to the max. 30 seconds on turbo is great, let it burn” idiots. Balance in everything. This is not a torch, it’s a lantern, designed for the long-run. Don’t over-stress anything, keep it to manufacturers’ data sheet parameters, then it might be supremely reliable and out-last most of us.

PS: that does mean that a FET has no place in this driver, in case you missed that.

I think I used that excuse already, not sure if she’s going to fall for it a second (or is it third) time… :stuck_out_tongue:

@Tom Tom, we are using the FET as a linear regulator, not in a direct drive setup.