Keep in mind that any time the engine is above approximately 1000rpm the electrical system will be charging the battery at 14.5 volts. A fully charged 12v lead acid battery is actually 13.6v. The 16v capacitor won’t last long, the 25v one will likely fail as well. We’re all used to battery powered lights and how to keep buck and fet+ drivers alive, vehicle electrical systems add in a whole new level of nasty.
The battery will eat a lot of the noise and harmonics, hopefully any capacitors added for noise filtering don’t turn into high pass filters. Tantalum and big are a bad combination for snubbing spikes, the internal impedance of the capacitor is just too high. Small and ceramic like Lexel suggested is best.
One thing I didn’t think of was checking the voltage across the led’s. While rare Cree does make six and twelve volt xml led’s, maybe latticebright does too.
Jerommel, yes back side is completly flat. Will do preheat, but very likely not that much.
WTF, so if I got it right I need ceramic capacitor like Lexel suggested, but for higher voltages 35-50V, right?
Measured voltage across leds showed 5.9V, so 2.95V per led now with added R500. It proves leds are ordinary china XM-L copy.
Next I plan to get stock leds off the PCB and connect some old SSC P7 to measure current across the leds.
Edit: Done that and also replaced R500 with R400. Got 1.83A to the leds (previously .73A with R500 in place). Still not that much. I might try R330 instead of R400.
If you want to scare yourself silly, learn about what really happens in automotive applications, and why this sort of lamp has not the least chance of proving durable, however modded.
Without at the very least least an automotive rated TVS diode across the input, and some knowledge of the likely resistance of the wiring harness. No, never connect even properly designed accessories directly to the battery, or worse still the alternator. Build an accessory harness instead, with suitably rated wires, that also add suitable resistance so the TransZorb might work.
Tantalum capacitors in particular are extremely fragile, they don’t like any sort of spike. Or reverse polarity (which happens every time you turn off the engine (alternator field coil decay). Plus there still seems to be no ethically monitored supply of tantalum yet, so I don’t use them on principle.
I can admit I don’t know anything about automotive stuff. Friend of mine have asked me to make lights he bought bit better and more bright. Now I’m discovering what and how to do. So the goal is to make it better. Also this two lights are add-on to the main light and is supposed to be switched on manualy when needed more light. In fact I’ve never seen the motorbike where it’s to be used. All I know it’s KTM adventure 990. Will tell friend to take care when to switch on/off the light to avoid some spikes.
Tantalum capacitors are just sitting in my drawer so I mention them. Since you all agree they are not good to use in this case, I won’t do it. Still hunting for proper ceramic ones at Aliexpress.
Last edit: changing current resistor from R400 to R330 gave me 1.92A to the leds. Will stop raising the current here (at least until I could get some additional capacitors and diodes which takes month or more from china). Input power raised from 9W to 15W altogether which is 2/3 more
With the new emitters and the current increase the modded light probably looks twice as bright now, there’s probably not much to gain by cranking it up much higher. Once the two lights are on the bike and added to the existing lights things probably wouldn’t look much different if you were to crank them to three amps. I wouldn’t worry about ordering the ceramic capacitors. Without an oscilloscope its hard to say if they would have any effect or possibly make things worse once the engine is running. You’ve got the lights making solid output with good safety margins on all the components, probably not much point into sinking more time and money into them.
Not sure what the motor bike lights produce but it is possible your two lights may have equal or more output than the existing high beam. I just looked at the Aliexpress page. Hopefully they’re the spot lights, you know what its like riding a bicycle at speed with too much light close to the bike. The flood lights on a motor bike at triple the speed could be dangerous if they make long range vision less effective. I see the advertised lumens and voltage ratings as inaccurate as they normally are. While they lack honesty, at least they continue to be consistent.
I run a BMW R1100 GS, one of the last made with comprehensible electronic systems, and no emissions management. I can ride it anywhere in the world, with just a retarding Hall effect crank sensor to match it to the lower octane petrol. Never had to fit it yet though. 5 minute job.
The KTM will be running with a CAN bus system, so adding extra lights (without controlling them over CAN, and not homologated) means that you are on your own. And if the owner lives in Germany, for example, it’s absolutely not allowed, they do like their TÜV regulations.
Whenever I go to Germany, other bikers look enviously at my setup and explain just how illegal everything that I have done would be there. The mountains of paperwork and inspection (fees) for every tiny mod.
You can’t even change the tyres for something that isn’t on the approved list, and even then they have to be changed as pairs, (or quads, in a car) even if only one is worn.
Which is good, because second-hand part worn German tyres are quite popular in the UK, particularly the high performance ones.
They have really really tried hard to impose this throughout the EU, fortunately resisted, so far.
OK. I’ve reflowed leds with moded hot air gun to narrower nozzle (using copper sheet). First I’ve used capton tape to cover all electronics parts, then used alu foil over it to take some excesive heat from hot air away. Preheated board from the bottom then using hot air directly over the led. It was rather easy.
All in all added R33 resistor to use 66% more power and changed the leds:
