Please help me build a frugal caving light - driver choice?

Wilburforce

Newly Enlightened
Joined
Jul 10, 2014
Messages
30
Hi there,

I'd like to make myself a frugal simple 3D printed caving light.

I'm new to actual flashlight electronics though rather than just buying drop ins and custom torches and Zebralights and Malkoff and OLight etc

Will 3D print the light housing and battery case and spot weld and shrink wrap my own battery pack out of either 18650/26650/18350... In parallel so 3.7 volt options only. Simple optics and a simple clicky switch on the top or side. Wire exiting then around to back of helmet and battery pack etc.

What I'd like is

A frugal driver - basically I want the high to be running at 1000-1400mA so I get nice long run times on high from a 6000mA battery pack etc and it doesn't heat up dangerously in a 3D printed case...

Probably a linear driver as simple to start with and running things in parallel..
Pref heat and polarity protection (although as using JST connectors this is really irrelevant an issue)

While I'd quite like eventually 2 LEDs - one spot, one flood, perhaps running off one switch although could be 2 switches. I will compromise with a single to start with or a board with 3 on.

Would like
Warm/Neutral - 4000k or 5000k
High CRI
No strobes, no hidden modes etc.
3 or 4 modes - ideally something like 1-5%, 33%, 66%, 100%
So it's something like 50mA, 350mA, 650mA, 1000mA (possibly 1400mA total if 2 LEDs and the mid mode would drop too)

I'm thinking XP-L or SST-20 but I'm also not sure about XHP ones and I don't really have any knowledge of many new ones as don't buy a lot of new flashlights anymore. Quite a few new LEDs seem to have emerged in the last few years when I haven't been so active on the forums.

Happy to have 20mm or plus boards.

What I'd mainly like some help with is finding a decent driver that doesn't have strobes/SOS and is frugal - too many I have been trawling through on AliExpress are all about pumping massive amounts of mA…
And I don't want to have to tap 8 times and count blinks to set modes.

Also the 7135 drivers all seems to have % groups I don't like. So is there anything I'm missing that hits the spot?

An A17DD-L FET + 1 driver?

I'd even be happy with a constant single mode light running 800mA or some such to start a build off with.

Thanks
 

kerneldrop

Flashlight Enthusiast
Joined
Apr 24, 2021
Messages
1,830
Location
South
Also the 7135 drivers all seems to have % groups I don't like. So is there anything I'm missing that hits the spot?

An A17DD-L FET + 1 driver?

I'd even be happy with a constant single mode light running 800mA or some such to start a build off with.

Thanks

You'll probably have more success posting that over at Budget Light Forums.... that's where the frugal builders hang and would eat this project up --whether good or bad.

Here is a frugal $4.20 multi-mode driver: If this driver doesn't work send an email and he'll build you anything you want.
 
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DIWdiver

Flashlight Enthusiast
Joined
Jan 27, 2010
Messages
2,725
Location
Connecticut, USA
Okay, a few things I notice. First, I'm glad you didn't say you wanted it for cave diving. For caving, an experimental light must have a backup. For cave diving, you must consider any experimental device as useless for safety.

It sounds like you use the word 'frugal' to mean you don't want to spend much money on it. That points you directly at 7135-based drivers that have a highly configurable user interface (UI). There are several of these around, and others will point you at them better than I could.

You mention heat protection. This is almost never included in any drivers. I say 'almost' because I don't know every part available, but I've never seen it on any driver that I didn't design. There are options to provide this protection outside the driver, but they aren't exactly 'small' in flashlight terms.

Reverse polarity protection is much more common, but not free, so you won't often see it on really frugal drivers, but it is sometimes there. Sometimes they tell you it's there, and sometimes they don't. If you have questions about a particular part, you should ask.

I'd suggest your modes be more like 100%, 25%, 6%, 1.5%. A lumen difference of 2:1 is not imperceptible, but neither is it 'large' to a human. For a 'significant' difference, you should have 3:1 to 5:1 difference between steps.
 

alpg88

Flashlight Enthusiast
Joined
Apr 19, 2005
Messages
4,182
You mention heat protection. This is almost never included in any drivers. I say 'almost' because I don't know every part available, but I've never seen it on any driver that I didn't design.
I'd hate to disagree with you but all 7135 drivers have heat protection, 2 layers actually.
1 amc chips have internal heat protection, they shut off when too hot. had it happen all the time when powered from 4x nimh. and no heatsink.
2 there are trace circles on both sides of 7135 driver, it is where fat ground pins of 7135 are soldered, in theory when the driver is installed, those circles are pressed against by pill/driver retaining ring, they are supposed to make a heat path from the driver to the body/pill.
but when such driver installed in a light that does not have proper fit pill/ring. they do not have that layer, what i used to do, i'd use thermal glue to glue aluminum pieces on both sides of the driver, and it did the trick.
I build a camping light in a hurry, so it looks sloppy but works pretty good, i had to install massive heatsinks on both sides of 7135 driver, When i feed it with 6v both heatsinks get pretty hot, if ran for hours, too hot to hold, but driver keeps ticking. those are pretty durable drivers.
P.S. If by protection you meant dropping output when the LED is hot, then no it does not have such ability.
 
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