Dimming LED auxiliary lights is harder than I thought it would be. Out of the box, the auxiliary motorcycle lights, brought from eBay for £30 (see Aux Lights for Less Than £80), are too bright, and the beam is unfocused. Exactly how an auxiliary light, the primary purpose of which is making me more visible, can be too bright is a bit beyond me. But this, it seems, is the problem I have.
If I didn’t also want to use the lights at night, then dimming the LED auxiliary lights wouldn’t be on my agenda. I’ve only had one complaint about the lights when riding during the day, and if it wasn’t a cliché to say it was an Audi driver, I’d tell you it was an Audi driver.
But as the daylight fades, I’m getting a few flashes from oncoming vehicles. Not everyone, but enough to make me think I needed to reposition or dim the auxiliary lights.
I’ve pointed the offside light more towards the curb and angled both lights down well below the cut off for my dip beam. As I still get the occasional flash from oncoming traffic, the problem may be light scatter rather than just brightness.
I know nothing about electronics, so I’ve taken my own advice and sought out people who know what they are talking about. Their collective advice has led me (no pun intended) to purchasing a Skene Lights IQ-275 from the Adventure Bike Shop in Suffolk.
Add to that a new switch – sadly still not illuminated – that has two on positions and a plan to wire it all up so I can run the lights on full power or reduced power, with a flick of my new switch, and I’ll soon be back in the garage, fiddling.
In other news, I’m getting very good at removing the KTM’s headlight without having to strip off all of the Tupperware.
Internet Advice
This is the part where the lawyers insist that I remind you that I’m an idiot and to seek professional assistance before modifying anything on your motorcycle.
If I had taken my own advice earlier, I could have avoided trying to dim the LED auxiliary lights with a dimmer I bought on Amazon for £10. It is something called a constant voltage dimmer, which doesn’t work.
As to what a Skene Lights IQ-275 Pulse Width Modulator – I kid you not, that is what it is called – is exactly, I have no idea. Yet those that know tell me …
A Pulse Width Modulator is a nifty device that reduces the average power delivered to the auxiliary lights by effectively chopping the power delivery into discrete parts. This way, the average voltage and current fed to the auxiliary lights can be reduced, and the auxiliary lights thereby appear dimmer. [electrickery – it is all voodoo]
It sounds backwards to me, but I’m assured this works. The downside is that PWMs can create electrical noise, although that is less likely to be a significant issue in today’s digital world.
Why Not A Canbus Controller?
Rather than using a three-way switch (On-Off-On) to select my auxiliary lights’ power output, I could use the high beam to trigger the lights to go to full power.
As the KTM has a canbus system, I’m unsure about doing this. If the canbus system thinks the change in wiring or the IQ-275 is a “fault”, I will forever be clearing errors. There are brighter minds than mine that can tell you if this is a good idea or not.
My preferred way to use the high-beam circuit on the KTM (or BMW / Harley) would be to use a canbus controller (Hex Ezcan or Denali), but that is an additional £200.
My three-position switch solution keeps everything out of the KTMs main wiring, and I can remove it all if I need to by pulling out a couple of connectors.
Dimming the LED Auxiliary Lights
At £80, the Skene Lights IQ-275 has doubled the cost of my auxiliary lights, but the new £160 total is still half the price of a pair of branded lights and with more functionality than some.
I could also remove the cost of the relay, had I known I’d need to dim the overly bright auxiliary lights, as the IQ-275 also provides that functionality. It isn’t a massive saving – £9 – but as this is all about being cost-effective, it is £9 I could have saved.
As I’m going to replace the relay, change the handlebar switch and fit the IQ-275, the easiest approach is going to be to remove all the wiring and start again. The wiring diagram from Skene, shown below, looks confusing, but the online instructions appear clear enough. And as we often ask … What could possibly go wrong?
And while I wait for the Skene IQ-275 Led Auxiliary Light Dimmer to arrive, the sun is out. Best go and enjoy it.
Clarity
The header image used in this article is based on an original photo by Tobias Reich
