Planning to build my ideal headlamp

Flashlight Modding and DIY Parts
1

I find headlamps extremely useful for work as an electrician, most of the work I do is in poorly lit environments. I use my Skilhunt H03 with LHD351 and anduril at the moment and it’s nice but I think it’s a bit heavy and it is missing some features. I don’t need more than 150 lumens either as I only use it indoors. So I am planning to build the ideal headlamp for my application.

Here are some features I would like to implement:

Lightweight (<50grams)
Nice tint and beam, 45 degree tir optic, SST20 4000k
Infinitely variable brightness
Fast usb c charging
Battery level indicator

I will probably 3d print the housing in petg plastic, similar to the usual plastic headlamp style like the Nitecore NU25 for example. I might add a piece of 2mm aluminum for the rear side for mounting and cooling the led.
I will use a CN5711 (linear constant current) based driver board and limit the current to about 500mA. I will replace the potentiometer to a alps style with built-in switch.
I could add a attiny13 based battery indicator that blinks out the state of charge when the headlamp is powered on.
I still have to decide on the battery, I think 600 - 800mah would be sufficient. There are small quadcopter cells that have high c ratings so I think those would be able to charge quickly without taking too much damage.

Here’s the parts list at the moment.

2

Looks like a fun project. Why not the LH351D? I think it is a bit more efficient than the SST20 and from Digikey, you can get it in 3500K or 4000K 95+ CRI.

Either way, please update this when you are done. I agree about limited amount of lumens for a great runtime. Unless I am outside, 150 lumens is enough. Maybe if I come from a sunny area into a dark area, I need more for a few minutes, but that is not that often.

3

4000k LH351D’s are difficult to order with reasonable shipping costs to Europe. I have some 5000k from arrow that I use in my H03 but they are a bit too cool in my opinion. I have some 4000k sst20’s already so I’ll start with them. The LHD351D would indeed be better suited with it’s large die thus improved efficiency.

4

Looks like a good project!

Since you don’t need max lumens, you may want to consider a 4000K Nichia 219B. Excellent tint and high CRI. One of my favorite LEDs.

5

I think Sofirn sells 4000K LH351D emitters with pretty reasonable prices/shipping.
They don’t sell them on MCPCBs, but it’s still an option if you can reflow them yourself. And cheaper than other trusted sellers I’ve read about!

6

“…a bit heavy and it is missing some features…”
Its 1 of lightest headlamps for 18650 and the best host for modding …wondering what futures it missing ;))

7

Makes sense, and like the other poster said, check Sofirn’s website, they have the 4000K and the 2700K LH351D’s.

I really like your overall idea, simple, light and efficient.

8

Why do you need a lens? Bare LED will give you a nice wide beam and will save you a lot of space.