Making a DIY caving light

Other Types of Lights LED Headlamps
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Hello, im new to this forum and the world of flashlights.
Im designing a caving light. It should look something like Scurion, El Speleo, Phaeton ect.
Im thinking of using one Cree XM-L2 led and other Luminous SST-40.
Thinking about two 21700 batteries connected in parallel for 10000 or 12000 mAh of juice.
I will use carclo 20 mm optics, one for spot and one for flood, or just one for spot.
Im looking for a driver that can run leds in few mode like 25 50 75 100 percent or smth like that. No strobe or SOS driver from Aliexpress. I know that sst-40 is maybe an overkill? it gets pretty hot on higher amps.
For battery pack and casing i already have an idea for CNC milling and 3D printing.
As I said im a begginer in electronics and flashlight designing so I ask you for advices or any ideas for my project.

  1. Im thinking of pre made driver…any suggestions for that setup 3.6v…
  2. Is there a way to have heat regulation and battery status level in a driver?
  3. What are the things i need to take in consideration generally?
  4. What sites to order stuff from ( Preferably Europe)
  5. How doable is this for someone inexperienced?

I would like to post updates on this topic here about the project.
Kind regards,

Cvil3

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You’re going to love it here, Cvile!

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1 Thank
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I bet I will :smiley:

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Welcome to the forum!

What you propose is certainly a significant scope of work, but without knowing your skill level it’s hard to advice whether it’s feasible for you to achieve.

I’ve seen new users ask similar “is it possible?” Questions with mixed results. Perhaps when I have time I’ll curate a list of these to encourage other beginners.

Some comments I hope are helpful:

Any reason these two in particular? For flood you could look at the 3v XHP LEDs, for spot SFT-40.

Think about what colour temperature you want. Cool white is brightest and most efficient but can wash out colours.

You’ll want a 2 channel driver to control the LEDs separately. Due to the nature of how we perceive brightness, you need 4x lumens for an apparent 2x brightness.

Don’t discount a low mode, you might be glad of the long runtime one day…!

This seems reasonable, if you build a 1S2P pack don’t forget a BMS. You could also put the cells in series with a 8.4V BMS, but driver options are a little more limited, I think. Always use quality cells from a reputable supplier, and ensure they’re “matched” (same make/model, same age/history).

It is also possible to use a cell carrier (if you can somehow make something waterproof and easy to change the cells). Just be mindful the cells should be a similar level of charge before you put them in the carrier else the higher charged one will try and charge the lower charged one with a LOT of amps.

Okay cool! If you’re good with CAD and can get stuff machined, then I think this project is feasible. In my opinion, the housing is potentially the most difficult step to get right.

Most of the flashlight specific gear I’ve acquired is from China.

Good places for stuff are https://kaidomain.com/ for lenses, optics, switches, o rings, drivers, LEDs;https://intl-outdoor.com/ for drivers (have to send Hank message), o rings, lenses, emitters; https://convoylight.com/ for emitters, drivers, lenses, optics, switches.

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Hey gravelmonkey, thanks for the reply and ideas.
I wanted parallel just for the runtime. I was looking at xm-l2 just becouse it is known as reliable and good emitter at its max 3A and i already own a caving light that uses two of those (doesnt mean its the best choice)

What are pros to SFT over SST?
SFT (if im not mistaken) only comes in 5700K or higher kelvins while SST has 5000k version.
SFT is domeless so its better suitable for spot but i dont know can it fit carclo optics? its 2.25x2.25 in size
Do they heat the same?
Do you know any specific driver for that needs?
Talking about XHP led…do you mean like 3up or 4up versions bc i know they work on 3v but pull crazy amount of amps.
Thanks again for your answer, helped a lot to start considering different configuration.
Hope you reply back :smiley:

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SFT have no dome, SST have a dome.
No dome equals better throw which you surely want for the thrower portion of the light.

Since those LEDs are dirt cheap at Convoy, I would say you should just buy a selection and test them yourself.

My list would be:

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Maybe you can see, which of those LEDs I like the most :smiley:

The SFT25R would probably be the best for throw since the DIE is the smallest of those that I chose.
The 519A has the best light quality of them all.

The LMP is my favorite right now because it is super cheap and gives a lot of light that is a super nice cold white. Like, super super nice.
I usually don’t like cool white light, that’s why I alsways chose the 5000/5700K Version, but the LMP is just so perfect cold white!

Convoy has plenty of drivers, but which one will depend on how your case will look like and if you want a light that you usually use at ~50% but want that overhead for short uses or if you want to use it at 100% all the time.

Also - do you want both LEDs to be on in the same time or do you plan on having them seperated? That would make the driver search 200x more difficult.

I would use a single 21700 and carry some replacements - if you have a 2x21700 Battery Pack you cannot just switch it out if you need to.

Also, let me leave this here…

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One option is to use separate driver for each led and have 2 switches. One switch for each led/driver.

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Hahaha, thats about it from the photo…Well I was thinking while flood is off spot is on and vice versa, not at the same time, if there is a driver.
I was thinking Dr.Jones or Led4power, taskled is too pricy with shipping…
Can I drive each led with its own driver and still have only one push switch?
I will sure check convoy, thanks :smiley:

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Dual channel drivers are rare. Those would allow you to use 1 switch for 2 leds.

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What is a caving light.

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I think the actual reason you want parallel is for “off-the-shelf” driver availability. 2x 21700 arranged in parallel or series have the same watthours, so runtime would be the same.

Think this has been answered satisfactorily.

No I mean for your floody channel a single XHP. They are available in 3V if you’re limited to 3V LEDs due to whatever driver you choose. LEDs in triple or quad arrangements don’t get hotter then a single LED, assuming you’re producing the same amount of lumens for each arrangement. The multi-led setups often push more current for more lumens, which obviously means more heat.

This is a good suggestion, however, I’d suggest a backup single 21700 and a waterproof connector. If you’ve a parallel battery pack, the voltage is the same as a single 21700.

I’ve not seen L4P gear for a long time since they closed down their store.

Most of the e-switch drivers Hank (Emisar) uses are dual channel… No?

Ruggedized headlamps specifically designed for caving activities. This is a search engine question if you’re genuinely curious…

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I found this reddit post:
https://www.reddit.com/r/caving/comments/teox37/diy_caving_light_coming_along_housing_and_lense/

And I find it quite interesting.
What about two triple or quad 3535 boards with different lenses?

Convoy has 10, 30 and 60° for their Quad boards:

Board:

Then you wouldn’t have different light colours.
Maybe you could also use just one driver and a on/on switch between driver and LEDs to choose which one you want to use?

Maybe a very throwy light in your hand? Comething M21B or C8 size with one KW CSLNM1.TG

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Yeah, he offers dual channel drivers. Not the most efficient ones, but they work. OP should also look how current dual channel Anduril works and if it’s what he wants from a caving light.

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