HPI light coil cure pt. 2

So, after trying out a LED headlight bulb that will work with the weak light coil in the HPI CDI it was bright but only glowed bright because the light went straight out the front and not into the reflector.

This is a stock headlight at night-

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=DSCF0620.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/DSCF0620.jpg" border="0" alt="Pinto Headlight at night"></a>!

This is what a 5W LED looks like at night-

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=DSCF0623.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/DSCF0623.jpg" border="0" alt="LED Headlight at night"></a>!

As you can see the LED is bright but no beam, and the stock light is dim but all beam.

Side by side durring the day they look like this-

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=DSCF0618-2.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/DSCF0618-2.jpg" border="0" alt="Headlights - led vs bulb"></a>!

I found a wedge base bulb that has 15 LEDs that are arranged to throw light radially as opposed to straight out the front (3 at the tip + 3 X 4 sides).

I used a burnt out LED bulb for the 1158 socket base and the old material from the dead bulb to fit the wegde base bulb into the 1158 base and soldered the contacts and glued the bulb into place.

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=newbulb.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/newbulb.jpg" border="0" alt="New LED Bulb"></a>!

It worked, but flickered really bad. That was because the new bulb is only an array of LEDs and DC by nature, and magneto coil systems produce AC current. So I added a full-wave bridge rectifier to it. That made it twice as bright but the flicker was twice as fast. I added a 100uf capacitor and that took the flicker out and it works awesome.

Here are the components-

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=components.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/components.jpg" border="0" alt="Headlight components"></a>!

The capacitor is on the left, the bulb in the center, above and below the bulb are the wires that make a splice connection for the capacitor, and on the right is the rectifier. The rectifier converts the AC current generated by the coil into DC current. The capacitor is a filter that smoothes out the fluctuation of the current (the flicker in the light). I used barrel connectors on the capacitor so I could try out different capacitor values. I found that 100uf gives the fastest response with the least drain on the circuit.

Here's what the mess looks like hooked up-

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=allconnected.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/allconnected.jpg" border="0" alt="Headlight all connected"></a>!

I'll get a pic of the beam it throws at night when I can, but these should give you an idea. The first one is of the bulb and stuff installed in the headlight bucket. The other two are of it running from two different angles.

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=Headlighoff.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/Headlighoff.jpg" border="0" alt="Headlight off"></a>!

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=Headlighton.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/Headlighton.jpg" border="0" alt="Headlight on"></a>!

!<a href="http://s651.photobucket.com/albums/uu237/samsporter/?action=view&current=Headlightonfromabove.jpg" target="_blank"><img src="http://i651.photobucket.com/albums/uu237/samsporter/Headlightonfromabove.jpg" border="0" alt="Headlight on from above"></a>!

When I first put it together and tried it out, the bulb was protruding (sticking out) badly and made a dark spot in the center of the beam.

It wasn't easy but I moved the bulb deeper into the socket and that focused it perfectly.

This new design is really impressive at night. The light is a cold white light but it lights up the road incredibly.

I used the idea that a regular bulb isn't really that bright, but it emits light all around it that is captured and focused by the parabolic mirror of the headlight. So I went with an LED bulb that does the same and the results are even better.

HPI light coil cure pt. 2

will you make me one? I'll pay you!

Re: HPI light coil cure pt. 2

I would make more if I had the time.

Save some cash and make one, here's what I used and where I got it from.

WLED-CWHP15 (194/168) wedge base bulb from http://www.superbrightleds.com/mini-wedge.html

1158 light bulb base (also at superbrightleds.com)

4 male slide crimp connectors

4 female slide crimp connectors

2 male barrel crimp connectors

2 female barrel crimp connectors

Full wave Bridge Rectifier 4amp 50PIV (Radio Shack part #276-1146)

100uf capacitor (Radio Shack part #272-1016)

14 ga. wire

heat shrink tube

Use the pics above to see how it all goes together. I used a red sharpie to mark the positive and black to mark the negative terminals. The "~" terminals on the rectifier go to male slide connectors that plug into the wires that normally connect to the socket, polarity doesn't matter with those two wires.

The LED bulb is the most expensive part ($17) but everything else is real cheap.

Re: HPI light coil cure pt. 2


lets see the beam at night.

im currently running the hpi cdi, with 1156 bulb from super brights.

its bright to look at, but your right. It doesn't throw a beam at all.

great for night time sketchy flying if you ask me, but alas I'd like a beam

Re: HPI light coil cure pt. 2

thanks, I was trying to be lazy but I am totally gonna do it . thanks for the list and the good instructions!

Re: HPI light coil cure pt. 2


Hey samsporter, EXCELLENT work! As far as projection, does the beam illuminate as far out ahead of you as a filament set up? With the DC conversion, does the light still glow at idle or does it only come on into the revs? I would also like to use an LED as a tail light bulb, so would the rectifier/capacitor setup be necessary for that too?

Thanks in advance! I've been trying to figure this stuff out for days haha.

Re: HPI light coil cure pt. 2

still waiting on pictures, also I found 2 side emitting leds that are already 1156. waiting on them to arrive then I'll give a verdict and maybe they'll save more time

Re: HPI light coil cure pt. 2

Someone has got to try and re wind one of thease coils.

I would but I dont got a cdi :(

Re: HPI light coil cure pt. 2

The beam is so much better than the filament setup, it's damn close to a car headlight. I use 1156-R24 for the taillights. They are from superbright leds also. With those you don't need any rectifier capacitor mod, they have them built in to the bulb already. And they look sick in the treats "Lexus" taillight. At iddle the headlight bulb does go out, but it's back with just a hint of throttle. I'm still experimenting with different capacitor values, it seems the larger the value the longer they delay in responsiveness to throttle. The low end of the value spectrum brings back the flicker.

Re: HPI light coil cure pt. 2

Bringing this back still....


I ordered 1156 in white from here. waiting to arrive

Re: HPI light coil cure pt. 2

King Drunky JCams /

After some searching about HPIs and lights... I found this post.

I was all excited to do this mod.

Then I read this:

"At iddle the headlight bulb does go out, but it&#8217;s back with just a hint of throttle."

I wanna go HPI, but I must have lights at all times...

So, is there no way at all to make a HPI system have nice, functional lights (headlight, tail, and brake) even at idle?

If not, somebody needs to get rich by finding the solution...

I'll buy right now.

Re: HPI light coil cure pt. 2

i got boz'd on the same thing.

Re: HPI light coil cure pt. 2

I have headlight and tail light with brakes.

do some simple math to figure out how much power your leds are really using. I think right now I'm at 7 or 8 watts total used between headlight and tail light.

My headlight doesn't go out at idle, slightly dimmer but most peds are like that anyways.

biggest issue is throwing an actual beam with leds. I haven't been able to work with mine using the side emmitting I received but we'll see how it works out.

Re: HPI light coil cure pt. 2

Bumping this. I just did this on my bike with an HPI, and it works well enough to be safe, but not quite bright enough for pitch-black riding at 50mph +. If anything it gets you decent lighting without running batteries, which is worth it to me. And yeah, you have no headlight activity at idle. I don't really care about the night time lighting beam too much, because this isn't a bike I ride around in the dark by myself on very often. I just want something that makes me visible to cars and this does the trick.

I'm running an 1156 tower bulb from super bright leds in a guia headlight. I'll try to get a photo of the beam it casts later, I guess.

Re: HPI light coil cure pt. 2

Like I thought, the light is bright but the throw kind of sucks. The bulb sits where a stock one does, and it's in a reflector, so it's the best I can do. Safe enough to be seen, and if you are running a HPI your bike will rev up so instantly that you will only be lacking light at idle. Just blip your throttle a little if you need cars to not run into you from behind. :)

Re: HPI light coil cure pt. 2

ok im gonna do this but im curious in what order do you put the rectifier and capacitor? curious.

Re: HPI light coil cure pt. 2

The diagram is right there in the first post.

Re: HPI light coil cure pt. 2

hmmmm cant see it

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