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Yet another Lux-RC / Easy2Led bike light

Training off-road during the colder days often also means that it’s getting quite dark. There are lots of bike lights on the market, most of them are either too expensive or not 100% satisfying. There’s however a simple solution using components from Lux-Rc and Easy2Led.

Lux-Rc light engine:

A small board, 3 leds and a boost regulator is already integrated, different configurations are available

Easy2Led light housing:

A good fit for the L33X light engine from Lux-Rc, in addition you’ll need a handlebar mount (Lupine or the Chinese equivalent that can be ordered at Lux-Rc), cables, battery, a momentary switch.


Input voltage depends on the light engine, mine is optimized for 2s Li-Ion batteries, I’m not going into detail about building a Li-Ion battery pack. This is dangerous, and you should know what you do, or better leave it. My battery pack has some additional heat-shrink tubing over each individual cell, heat shrink tube over the whole pack, and then a layer of plastidip liquid rubber on top of the heat-shrink tubing. Additionally, I’ve added some foamed rubber on the side that touches the frame when the Pack is mounted to my bike.

Oh yeah, and please use a little less thermal glue, maybe 1/3rd of what I’ve used should be enough.

14 replies on “Yet another Lux-RC / Easy2Led bike light”

Nice build. Very nice battery pack. You’re right about too much thermal glue.

Please go into detail about the battery pack. I’ve done a lot of research on batteries (Lipo, standard Lithium Ion, LiFePO4) and have decided I want to build a 2 or 4 cell pack using NCR18650A cells from Panasonic. But, the feature I really want is to use a balance tap so that I can charge the pack with my FMA CellPro Gold 4S charger.

Can you elaborate on how you soldered the balance tap, what batteries you’re using and what charger you’re using. Also what amp hour rate you use when charge?

You’re the first person I’ve seen that is using a pack identical to what I want to build.

Thank you in advance for your response. John.

Hi John

Good to hear that you like my light. I’m using the Panasonic cells as well (scavenged from a notebook battery pack). Balance tab is an important thing, and it’s easy to implement, you should check:

As a charger I’m using a Turnigy Accucel-6 when I’m at home and a Simprop Intelli-B Power in my personal “Hackerspace”. I prefer the Turnigy, the Simprop isn’t very good if it comes to balancing. Charging with ~1.3A, I guess I could easily go higher, but I don’t have a need for that, since I’m always charging after I’ve used it.

Have a good weekend, cheers

Forgot to mention, you might also want to add a protection PCB, but I personally think that this is not important, as long as you know what you do (always charge balanced, never overdischarge, keep an eye on the voltage…).

Thank for the reply Nico.

Two more questions please:

How did you attach the balance taps? What kind of soldering iron & tip did you use? I’ve heard it’s difficult to solder battery packs, but then I saw a video on youtube of a guy using a soldering tip called a hammerhead. How did you do it?

What charge rate are you using?

Thank you.

I’ve just soldered them directly to the cells. I’m using a dremel to carefully roughen the cell’s poles. After that, I’m adding little solder to it, and then I’m soldering the balance tabs and +/- cables in one step (I’m usually drilling the corresponding cables together, and then treat them as one).
You don’t need a hammerhead, it’s a good thing to solder on NiXX cells, but with li-ion I’ve never used it. You should be aware, that heat can damage the cells, or even make them dangerous. So you should do this quick, you’ll need enough heat to do it quick, but a normal soldering tip works good.

I’m using Weller wecp-20, standard tip.

Charging at ~1.3A, see my first reply.
Cheers, Nico

Thanks Nico. I’m going to try to put together a pack of 18650s using the solder technique. Thanks for your help.

Hi Stu,
It’s 30° when used with the XP-G leds that are on the Lux-RC light engine, I’ve ordered it with the light engine, from the confirmation mail it says:
“20mm Triple Lens For L333 LED Engine. Medium Frosted Rev.3 (FWHM: 26 XP-E; 30 XP-G). Optical Grade PC. Made in UK”

There’s no hot spot, it’s all flood, little brighter towards the middle – in my eyes this is perfect at the handlebar, if you have a second light at the helmet, I’d choose the helmet one a bit narrower (it’s what I’m working on at the moment) maybe 20°-25°.


Cheers Nico,

Thanks for answering quickly.

How deep is the optic? I already have some triple optics which are 6mm deep, but I am wondering if this is too shallow for the easy2led 20mm housing without adding a spacer. their drawing shows that it is 11.5mm deep, but I don’t know how much is used by the lens.



Hey Stu, I actually don’t remember, but I think that it could be about 6mm as well. The Easy2Led housing comes with a glass lens with a metal ring/thread, that I also put in place (I know, this is not as efficient as it could be). As you can see on the pictures at, the threading on the housing goes all the way in, so it should work anyway.

Cheers, Nico

Cheers Nico,

I have a couple of the housings on the way to try :).

I already have the larger 35mm one, which I like a lot.


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