Campsite lighting for ultralight backpacking - prototype

I’ve recently become interested in ultralight backpacking. I’ll purchase some BLF lanterns for sure, but they also aren’t ultralight for sure.

The useage is: 4 person group hike and camp over the course of 5 days/60miles, all at 9,000+ft elevation including two 14k peaks, and no resupply stops (i.e. carry all gear including 5 days food) so every gram counts. Use 2 (maybe 3, but testing appears that 2 is plenty) camp lights of ~150Lm each to light the small 20’x20’ campsite at night for drinking and storytelling (each hiker will have a personal headlamp).

Here’s my proof-of-concept (I shouldn’t even call it a prototype):

  • High capacity 18650 (magnetic leads)
  • Adjustable DC step-up voltage regulator set to 5.200v at the moment
  • XHP70 (will be xhp70.2) in 6V mode

Based on great feedback I got here on BLF (thanks kiriba-ru, others!), I used an XHP70 emitter I had available due to the extreme efficiency multi-die emitters can acheive at low currents. This setup measured 137Lm at 5.201v/0.060A across the LED for example. When I make the finished product I will use an XHP70.2 to hopefully get a tiny bit more efficiency. The output above equated to 0.090A from a 3.9v battery (88.9% efficiency from the step-up regulator, not bad!) and 0.12A from my power supply set to 2.9v (89.7%). Based on those number I’d be looking at 30+ hours of runtime, ignoring temperature influence (see below).

I only had a 12v MCPCB on hand, so I soldered lead wires straight to the LED. :open_mouth: At 0.06A there was no heat to worry about for testing, although the final product will be properly reflowed on an MCPCB.

Right now I’m playing with optics to decide between mule mode or using some optic. I’d love to find an elliptical optic for XHP70 footprint, but so far haven’t found anything.

I tried to use dedicated 5v step-up boards, but the LED output at 5v was too low, about 25Lm.

Currently the setup weighs 53.5g (the battery is 45g) without an MCPCB (2.5g).

Nighttime low temps could be as low as 20F, so I am considering replacing the 18650 Li-Ion with 3*AA Energizer Ultimate Lithium primaries because the Lithium primaries should perform much better at low temperature. The Li-Ion will probably lose a lot of capacity in temps that low and I don’t want to bring extra cells. There is no weight penalty as AA Lithium primaries weigh ~15g each.

I need to determine a good method to mount the lights for use, either hanging, or staked in the ground, or … still brainstorming that part.

The final product would have SOME simple protection for the LED, the PCB protected with some conformal coating plus electrical tape, and the hole thing will be generally cleaner looking, but overall not fundamentally much different than pictured.

Thoughts and feedback are encouraged!

No fires allowed. :frowning:

I’ve backpacked and camped for a long time and only recently drank the Ultralight kool-aid and am really liking it. I stopped packing my fears, no more “just in case”, no more “well it’s only a few ounces”. The Ultralight mindset has shrunk my pack from 20lb to ~10lb and it makes a huge difference in my comfort and enjoyment of the hike, as well as the number of miles I can cover (and how my knees feel from covering those miles). My base pack weight (everything other than food/water) varies from 7lbs for a warm weather overnighter, to 12lbs for this longer trip in colder weather.

Take only what I absolutely need to be safe, no more. And make the things I must take as light as possible. So in that regard, even these 55g lights are unnecessary as long as I have my nitecore nu20 with homemade headband (25g total). But, I will make an exception for these ounces, it makes a big difference for group camping.

Just want to mention that clamp meter is not best tool to measure mA.

I think I’d just take a 4Sevens Mini M2A loaded with a pair of AA Energizer Ultimates, and an el-cheapo Nitecore headband (worth about three bucks) and call it good. Light goes in your shirt pocket, band goes wherever. Weighs almost nothing.

Light for five nights? Piece of cake. Those things run forever.

Good point, it was easy though! Haha.

I zeroed it constantly and it agreed surprisingly well (<10% error) with the numbers coming from my power supply and the one time I double-checked with my better Brymen meter. So I know it isn’t ideal, but for proof of concept it did what I needed.

M2A in that configuration is a headlamp which I don’t need. For comparison I already have a 28g Nu20 CRI headlamp (total with band and battery) that does 30Lm for 7.8hr or 170lm for 6hr.

M2A weighs 28g for light only, the nitecore headband (single strap, not over-the-head) I’ve got here weighs 26g, two EUL Batts weigh 30g. That’s 84g total, three times the weight. M2A does 36Lm for 9hr, or 216Lm for 1.7hr.

I am building an area light not a headlamp, used to light up a 20ft x 20ft area where 4 of us will be preparing dinner, etc. The M2A idea will not disperse light across a wide area like a mule light will,and it also has nowhere near the runtime. If we used the M2A for 2 hrs per day, I’d have to carry an extra set of batteries even at the 36Lm setting. My prototype above can run around 30hrs at 137lm weighing ~60g.

those specs do not make sense

here is a real world test,
the 170 lumen mode drops to 10 lumens after 2 hours
the 30 lumen mode, is more like 20 lumens actually, and does last almost 8 hours
click pic for full review

Good point and I should have thought more about the mfg specs before I posted them, I know you can’t get 200lm for 6 hours out of a 600mAh battery. :person_facepalming:

But High & Turbo runtime don’t matter much to me in my use anyway. My actual use of the headlamp is something like:

  • 70% low (1Lm)
  • 29% med (30Lm)
  • 1% high (170Lm)
  • 0% turbo (270Lm)

A Lumintop EDC05 is tiny, and yields 100lm for 12 hours on a 14500. All for 56 grams.

Need another 12 hours? Add another 14500 for 21g more.

Put some dcfix or a cheap silicone cover on it to make a nice lamp.

And if you needed 800lm and decent throw in a pinch, you’ve got it with you.

That’s what I’d go with.

I think that is a great light for your application, thanks for sharing info

I do not believe that is accurate, maybe post a runtime chart to show what makes you believe that

look at this, its a similar light, it gets about 180 lumens for 85 minutes
click [Review] Manker E11 XP-L AA/14500 for full review

Hmmm yeah. I just did some quick math using the max efficiency of the EDC05 emitter and a 800mAh 14500 and at 100lm that would be 4.5hrs.

I must’ve been thinking of their overrated claims instead of reality. Sorry about that.

It would still be my choice for lightweight hiking though.

Those numbers did look off. From what I’ve seen the “sweet spot” for most AA lights seems to be around 50 lumens for 7-8 hours.

Here are stats from some common AA lights at low and medium:

Manker E03H (AA): 12lumen:30hrs / 50lumen @7.5hrs
Sofirn SF14 (AA): 3 lumen:111hrs / 33 lumen:10h27min
Sofrn SF14(14500): 5 lumen:100h / 110 lumen:5h 40min
Utorch UT01 (AA): 2 lumen:171hrs / 60 lumen:11hrs (seems a little too good to be true, esp compared to the Sofirn AA spec)
Utorch UT01 (14500): 10 lumen:44hrs / 100 lumen:12hrs

Just for one comparison point, the quite light skilhunt h03 (18650) does: 3 lumen:450hrs / 20 lumen:75hrs / 70 lumen:25hrs

You’re getting something like 3x the capacity for 0.5oz more weight.

Though i build or mod my own micro LED lanterns for Backpacking, the best one i have as a stock multi purpose light i bought is probably the single AA Manker E03H. I tested it running for 8 hours non stop on a Eneloop pro at 50 lumens. I added a small lanyard to the pocket clip so it can hang down as a hanging tent lantern using its slide-up diffuser. I need to post a topic with photos of all my mini lights i use for camping, and the mods i did with them some day.

Do! :slight_smile: