LED auxillary light?

I just wrote a LONG message, and when I pressed "send" I had been logged out = an hour of writing vanished! Lets just say that I am not very happy right now... So you get the questeon in very short form instead!

I have a moped with 45W incan headlight, and I would like more light (don't we all?). The available power is limited = I probably can not use the 60W bulb that is available. It is hard to get anyway...

I was thinking of 2*4.9W Seoul Z-power leds producing 178lm of 6500K light each as "auxillary" lights, ofcourse with some suitable lens. Also a few other changes are needed to make sure the power will be enough for the leds, but I really dont want to write all that a second time now!

Do you think a couple of powerleds used this way would make a noticable improvement to the light at night on dark twisting roads? From my calculations the 45W lamp only gives something like 550-600lm, so almost 360lm extra from the leds would seem like a big improvement - at least on paper. :thinking:

1.) Use a current regulating power supply.

2.) how about four of those 5-watt leds instead of two? You could have the only moped in town with high beams.

1: Absolutely, I never use LEDs w/o some sort of current control.

2: Two was the original plan, but that has changed now. It seems there are no lenses available for that LED here, the price is "a bit" high (5 pizzas or one LED, hmm...) and last but not least, lm/W could be higher...

New plan: Three Seoul P4 in series regulated by a LM317 and driven by the 12V battery. At 600mA (for example) they should deliver about 3*150lm, and all that just slightly more expensive than a single 4.9W. :thumbsup: If I'm happy with it another 3-6-9 LEDs may be added later, maybe even replacing the original high beam completely instead of just "adding to it" as i was planning.

Better low beam could be nice too later on. Does anyone know the best and simplest way to get a suitable beam pattern for low beam from LEDs?

A Cree XR-E P4 (quite inexpensive these days) supposedly produces 176 lumens from 3.7W, while a Cree XR-E Q5 makes 228 lumens from 3.7W. If you can't just swap in a brighter bulb then I'd recommend using them instead. The tricky bit would be getting a beam pattern you like. I've seen a few wide angle (elliptical) optics, though.

Is your moped 12V?

Edit: Took me a while to post that, and you had posted in the interim, so everything I said is already outdated. :sigh: Do you know about the Kennan board from KD? (Yay, they're in stock again.) It supplies a regulated 750mA and will be more efficient that using an LM317.

The effort is appriciated even if the info was outdated.

I have seen the Kennan board somewhere before, and it looks like a nice thing. But (there's always a but) I am trying to manage with parts easily available here in Sweden, mainly for easier ordering - and I don't even have a creditcard usable abroad now. The LM317 should be efficient enough to start with, we are talking about something like 1W diffrence. Bad in a small flashlight for sure, but nothing to cry blood over in a system with 55-60W generator and a 12V 3Ah battery that "always" is fully charged. If the power isn't enough even after replacing taillight etc with LED I can simply change from a 45 to a 35W headlight bulb.

What about replacing the existing headlight bulb to a single 35 or 50 watt HID set-up?

A HID conversion is in (very, very slow) progress. I already have one in a reflector that fits the bike, but... The generator only puts out something like 60W (AC) at peak rpm, at the rpm I mostly drive that is closer to 50W. Turning 50W AC into enough DC to power a HID, other lights, and also enough to charge the battery so that kan keep the HID lit when I drive at lower rpm or let the bike idle... Not very easy! Added to that, HID goes black when the battery is empty. Not something you want to experience by night on a pitch black road. In other words: I don't dare to use HID before I am VERY sure the battery never will end up empty.

LEDs may not give as much light and be more expensive, but they slowly go dim instead of suddenly just turn off.

On the subject of power output, I knew a guy who put air horns on a 50cc motor scooter. He had to be going downhill at top revs or it would stall when he sounded them.

But a standard 35W HID would use less power running than your present incandescent 45W bulb.

Yes and no. The ballast is supposed to draw about 40W, so the power consumption there would be a bit lower. However, the incan runs on AC straight from the generator, the HID needs DC and then you need to add the losses in the regulator/rectifier to the equation. 4A going through a full wave rectifier with 1V drop over each diode would cause a drop of 2V (wich in a way reduces the current the generator can put out slightly) and burn 8W.

So, 40W + 8W + some losses when charging the battery... I would need more power to use a 35W HID than the 45W incan.

I need a substantal generator upgrade before I can use HID. A rewind is planned, and hopefully that gives a bit more power. But I have done the maths, and judging by those numbers this generator just can't give me what I want no matter how it gets wound. And as it is a part of the ignition system and is made to fit this specific engine, changing it for something more powerful is hard and probably expensive. (On the other hand, there are plenty of racing ignitions that bolt straight on with a smaller or no generator at all. The irony...)



Another thing I thought of: The light from the filament goes in "all directions", quite alot becomes useless sidespill in one way or another instead of hitting the right parts of the reflector and lighting up the road. With a 600lm lamp, does even 300lm get sent where I want it?
A LED with optics seems better at making the light end up where it is useful, so wouldn't "led-lumens" give me more light on the road than the "lamp lumens"? :thinking: Just a thought...