First Aux Lights Mod

Here's a go at my first time modding & having anything to do with LEDs.

Wanted a set of Aux lights for my motorcycle and most cheap off shelf lights had lighting modes which switches when you toggle the on/off switch, which isn't practical while on the road, I wanted something that I could quickly turn off, will passing other vehicles and return to the set brightness settings.

So I decided to try building one, it's not completed, left the control buttons, but basically most of it runs now.

Still deciding what Amps to run them at for full power. (Please do advice or give any suggestions)

So here's a list of items i purchased & their cost. I bought mostly off Taobao.com, a chinese site which is really cheap.

I'm driving the LEDs at this settings:
3x6V = 18V @ 2.75A
3x12V = 36V @ 1.3A

I'm thinking if I can push the LEDs to these settings and if the lights can be in working temps, any recommendations?
18V @ 4.5A
36V @ 2.25A

Light bodies/case


Body 1 on the left, Body 2 - smaller one on the right.

Body 1

$25usd - comes with mounting brackets/clamp - Claimed 30w 3xXM-L2
https://world.taobao.com/item/44000857226.htm?fromSite=main

LEDs were wired in series, which made it easier when I am going to power 3 xhp50s, & i could reuse the reflectors.
Good thing about this light, it doesn't have any lighting modes, just on/off.
Measured off my LiFePo4 batts 13.5v drawing 0.7A... Works out to be about 3W per bulb. Looks way dim, so I'm not surprised.

Body 2

$14usd - just the body
https://world.taobao.com/item/551266403953.htm?fromSite=main

7 LEDs, wired in parallel. Really cheap. Couldn't remember the current draw I measured, but this was way dimmer than the first light i got(Body 1).
There is no way i could reuse the MCPCB as well so i ordered 3 XHP50 mounted on copper MCPCB, & got 3 lenses for it as well as the original reflector doesn't line up with 3 stars inside.

LEDs

3x XHP50 mounted on all copper MCPCB 12v

$3.60usd each - total $10.80usd
https://item.taobao.com/item.htm?spm=a1z09.2.0.0.1f30a53fVpRRRZ&id=525526937942&_u=41ui9qg9a729

3x XHP50 bare

$2.70usd each - total $8.10usd
https://world.taobao.com/item/552921202102.htm?fromSite=main&spm=a1z09.2.0.0.1f30a53fVpRRRZ&_u=41ui9qg900bc

3x Lenses

$0.22usd each - total $0.66usd
https://world.taobao.com/item/35720272414.htm?fromSite=main&spm=a1z09.2.0.0.1f30a53fVpRRRZ&_u=41ui9qg9ff53

Some photos of the MCPCB & lenses

Reflowed the XHP50s onto the original MCPCB of Body 1
Tested out the freshly soldered XHP50s to make sure i didn't destroyed them. 18v @ 1.4A, and left it on the floor with the LEDs facing down (it was too bright) and after 30s smelt something burning, and found my wooden floor burnt.

8 degree lenses
Checking fit of lens holders into Body 2

Electronics

Next I figured i needed a way to control the lights. Settled with an Arduino Nano and did some trial & error on the programming for it to work.

As on choosing how to drive (Buck or Boost converters) the LEDs & what Voltages should I use i took these into considerations.

The motorcycle electric system can range from 12-14Vs, so i decided to wire the 6V leds in series for Body 1 (not much of a choice as the stock was in series) & 12V LEDs in series too for Body 2.

As space is a constraint as well (wanted it to fit all nicely under the seat) I settled with 2x 250 Watt Boost converters.


2x 250W Boost Converter

$3.70usd each - total $7.40usd
https://detail.tmall.com/item.htm?id=525632257737&toSite=main

These are the white board & the one in the static bag in the photo above.
I had to have 2 boards cause 1 Body is running at 18v, the other 36v. I figure there will be efficiency issues, but figured a drop of 20% is acceptable.
Note: The module has a limit of 10A input & 10A output. If input is >8A, cooling will be required, or if output is >6A cooling is required.

So those factors I had to constantly keep in mind to no burn my bike down.

2x PWM Switch (I believe it's a MOSFET?)

$1.16usd each - total $2.32usd
https://world.taobao.com/item/540406913795.htm?fromSite=main&spm=a1z09.2.0.0.1f30a53fVpRRRZ&_u=41ui9qg9eb89
They are the 2 small boards connected (i haven't broken them off) in the lower left corner in the photo above.

Spec'ed at 400W 30A. Though recommendation room temperature upper limit is 15A. A bike internal working temp, I'm under the assumption it's 85 degrees celsius.
I'm using this to separate the driving voltages/current from the Arduino controller. The Arduino will have 2 separate PWM outputs to each of these, so in future, if i wanted to control either lights individually, i could.

Arduino Nano

$1.20usd
https://world.taobao.com/item/544996293668.htm?fromSite=main&spm=a1z09.2.0.0.1f30a53fVpRRRZ&_u=41ui9qg9ef3a
This is the board just on the right of the PWM switch in the photo above.

I was thinking of using the ATtiny, but I couldn't wrap my head out regarding the pin outs & PWM stuff, wasted a few days on it and couldn't get it to work, so i reverted back to the Arduino Nano.
I have 1x On/Off switch (with led indicator-which i power with the Arduino PWM to glow, the brightness of the glow corresponds to the current brightness settings of the main LEDs), 1 momentary push button ( so i can quickly turn off the lights while held down, if the main switched is off when this is pressed - i set it to turn on, sort of a 'high beam'), 1 Linear Potentiometer (to control brightness).

DC-DC Buck convertor

$0.60usd
https://detail.tmall.com/item.htm?id=548559287443&toSite=main
Small green board just beside the Arduino Nano in the photo above.

I needed a power source to power the Arduino, and since the Arduino doesn't need too much, this is sufficient. I must say this board is pretty versatile. It's tiny at 20 (L) * 11 (W) * 5 (H) mm! Also it has preset options that you just solder short to have it fixed at that voltage output (1.8V 2.5V 3.3V 5V 9V 12V), instead of configuring it with a multi-meter.
Board is set at 9V & connected to the Arduino Nano's Vin

Switches & Buttons

Switch with LED indicator

$5.20usd
https://world.taobao.com/item/37243475584.htm?fromSite=main&spm=a1z09.2.0.0.1f30a53fVpRRRZ&_u=41ui9qg9b70d
Stainless steel, IP67 rated (there are IP65 & IP67, not sure which one i got), 3-8V LED

Push Button

$3.20usd
https://world.taobao.com/item/520023996721.htm?fromSite=main&spm=a1z09.2.0.0.1f30a53fVpRRRZ&_u=41ui9qg95e74

Stainless steel, IP65 rated

Potentiometer

$11USD
https://item.taobao.com/item.htm?spm=a230r.1.14.21.ebb2eb2IKEx9F&id=525543620841&ns=1&abbucket=19#detail

Though it's not the most expensive component so far, but i can't help it's way expensive for just a little dial.
But it's the only one i could find that is IP67 rated, since it's going on my bike's handle bars exposed 24/7. :(


Arduino Nano mounted to a PCB and wired to a connector to link up to the Controls using a 8 core data cable.


Crimping the ends of the data cable for the connector.


How the Boost convertor & PWM modules fit into the small hobby box I have. Note the lack of active cooling, I'm figuring that most of the modules i'm running at less than 30% of what it's rated, so i can get away with heat management.

Here's how the Bodies with the mounted LEDs looks like.

Body 1 is the one on the left, it looks the Best, close to stock just with XHP50s in them. The light beam is much narrower than the other Body as well.

Mounting the MCPCB on Body 1 is easiest as well, as I just had to use some thermal paste (>6.0W/m-k), the metal reflector has a screw that goes through the aluminium housing that clamps everything down. But only concern is the MCPCB is Aluminium & heat dissipation


Mounting the 3 star 12v LED boards on Body 2 is trickier and honestly I'm not sure if it will hold up to the abuse & vibrations it will see on a motorcycle. The 3 star boards are first place down with thermal paste (>6.0W/m-k), then the spaces around are filled with some silicone that apparently is used for electronics, it has a rating of >1.5W/m-k ( not sure if this is enough?).

Finally, I'm driving the LEDs at this settings:

3x6V = 18V @ 2.75A

3x12V = 36V @ 1.3A

I'm thinking if I can push the LEDs to these settings and if the lights can be in working temps, any recommendations?

18V @ 4.5A

36V @ 2.25A

Total Cost so far $89.50

This doesn't include some parts like connectors, wires, shrink wraps, thermal paste & silicone, can't recall if i left anything out.

Cheers :D

For what is worth, I can't read Chinese. I studied it in grade school and failed.


Adding some light shots. Don't have any setup to test lumens & stuff. Only know light source i have is an outdoor Petzl head lamp to compare with.


ISO 100, f1.7, 1/16000, 3 feet
Reference : Petzl Tikka RXP @ 220 lumens

ISO 100, f1.7, 1/16000, 3 feet.
Body 1 @ Full, stock reflectors
3x XHP50 18V 2.75A

ISO 100, f1.7, 1/16000
3 feet
Original Light beam from stock lamp from Body 2

7 Leds - Claimed to be XML2 T6 but doubt so. Measured wattage draw on 13.3V battery was 0.7A, would be driving the each individual LEDs at about 0.3A? 1W per LED

ISO 100, f1.7, 1/16000, 3 feet
Body 2, 20mm 8 degree reflectors
3x XHP50 @ 36V 1.35A

https://www.youtube.com/watch?v=-A2LZJfspqg A short video of my main switch with a light indicator to show that the lights are on. It pulses in respect to how bright the main lights are depending on the potentiometer setting.

Some build photos

Beam shots

Shot @ ISO 100, f1.7, 1/45s

ISO 100, f1.7, 1/45
Bike's headlight on

ISO 100, f1.7, 1/45
Body 1 @ Full, stock reflectors
3x XHP50 18V 2.75A

ISO 100, f1.7, 1/45
Body 2, 20mm 8 degree reflectors
3x XHP50 @ 36V 1.35A

Nice build thread so far! But we need beamshots, impressions, etc. Before & after pics will have been awesome.

I have buddies that have been asking me to do just this, but I’ve held off so far. Curious to see how things end up.

+1 :wink: :+1:

…except for the part about me ever doing this. :smiley:

Sure thing!
Haven’t brought the lights out to try it. Waiting for my buttons to come in, as my previous test ones, I found too small to activate them properly with gloves on.

Smb should prevent you from using all this parts on motocycle. Motocycle devices should be able to work in hard conditions. Alternator output is not just 12-14V, it always have big ripples (up to 50-100v). Step-up converter and arduino ps dont like this ripples and may die soon. Using one big boost converter is not safety - better to have three smaller buck units - when one of them will burn, you will still have light.
Please dont trust chinese specs - you can always make simple tests and see how far are rated numbers from actual properties.
P.S. I hope you know that 20mm tir+xhp50 cant give 8° angle…

Thanks for the heads up. Will watch out for it. Sadly I’ve got no experience and knowledge on how to do a custom smb.

From what you are saying, first thing I need to do is to protect it from high voltage ripples?

Thanks for sharing! As for max current, I think you will have to do some tests on your own to determine max current. Make sure it runs cool enough with modest settings then go up from there. I’m thinking that you won’t be able to go much higher, but maybe a little?

Another problem is that your lights dont have any current limit. Leds are restricted by boost converter voltage, which itself is restricted by input power, while pwm board cant influence to peak led current (it adjusts average current). This method is widely used in flashlights that have limited cell capacity and fast voltage drop. With unlimited power supply, leds peak current will increase as leds will get hotter.
I dont think you should make changes right know (you can change parts when they will be broken), but next time you should try to test spare boards before you put them together.

The dc-dc boost converter has current and voltage limiter. Which I’ve set to limit at 1.25A & 2.75A.

I’m ok with things just blowing and stop working, but worried if anything would actually catch fire. Also they will be all connected through a fuse to the battery.

I don’t think anything will catch fire but do you have a way of measuring temp for testing? If not you can judge 60C by being able to touch for 1-3seconds depending on how brace you are. Above 70C you will have to pull your finger away. :slight_smile:

Components that are not reachable by fingers can safely run 85-100c but I don’t know how to test that by touching;)

I don’t have any instruments for measuring Temps. I’m ok with the light bodies getting hot and fail. But i’m more worried about the power convertors getting too hot, as they will be hidden n tuck away under the pillion seat. Also the power convertors & electronics are enclosed in plastic box, so i think they will melt before hitting those temps?

Currently leaving the lights on for about 10mins, Body 2 gets quite hot, almost too hot to grab hold of it. Body 1 is slightly warm and holdable.

Also added some shots, to the original post, of the lights against a wall

“Almost too hot to hold” sounds like it is cool enough to keep from burning but if the heatsinking isn’t great you know that the temp at the led is much higher. Still the led can opporate at 125C and be fine. If your lights start to turn blue or start going toward the cool side, back off the current as they are about to burn. :frowning:

Your boost converters can still be heatsinked to the outside the box without loosing its seal. They can be bolted to a piece of aluminum bar inside the box and then the bar bolted through the box to a small CPU or video card heatsink on the outside. The more bolts the better and preferably made of aluminum. The trick is to put an oring or use silicone gasket maker under the heatsink. I saw someone do this for something, somewhere, at some point in time:) It’s a lot of work though.

Mmm when setup, I’ve got no way to back off the current, would it be the same if I turn down the pwm duty cycle to not run at 100%?

Yes the heat sink sounds like alot of work, and currently I don’t have any more space to make the box any larger than it is. Also the box is not sealed, I’m going on the assumption the area under the seat looks pretty dry after a heavy thunderstorm.

I’m now getting interested it doing a custom diy circuit to have all the electronics in one piece, any advice where can I start looking at?

Hmm… idk? I think you’ve done well. Maybe you can push through and get it going. Then you can decide what you like and don’t like and what works and what doesn’t. You have everything together and you are so close to being finished I think you should give it a try for a bit. No?

Thanks. Yes I definitely will. Currently just awaiting for new buttons to come in, cause the initial 16mm ones were too finicky to operate with gloves on.

Also awaiting for other bike parts to arrive and bring them to the workshop to get it nicely installed at one go.

Give us some pics when you get it together:)

Edited post, added some beam & build shots.