Rewinding HPI light coil and/or replacing it.

Decided to start a separate thread on this. Has anyone tried rewinding the HPI light coil? I dont have one too look at, does it have any more space for extra wire?

Re: Rewinding HPI light coil and/or replacing it.

roadent$ craig /

i personally dont want to rewire mine... yeah it has a low output... better than blowing bulbs with a coil that has an unknown amount of power. it might be a little dim at idle but will be bright enough once it starts revvvvvvvvin

Re: Rewinding HPI light coil and/or replacing it.

Here are a few bookmarks you might find helpful.

http://home.comcast.net/~pgailunas/stator.html

http://www.xr650r.us/stator/

Re: Rewinding HPI light coil and/or replacing it.

Craig, are you running a headlight and a tail light? How many watts is your headlight?

Re: Rewinding HPI light coil and/or replacing it.

roadent$ craig /

i havnt tried mine out yet... but ill try bulbs until i get a good combo. i hear the hpi coil pumps out ~10 watts.. thats enough for 2 lights; no brake light.

Re: Rewinding HPI light coil and/or replacing it.

Aha! Saab, that looks like a good resource :D

I think whatever you do, you need a pretty light load on the coil. The load should be dissipating 10W at 12V. You have to match the load to the coil to get the maximum power dissipated in the load.

I posted up some measurements, but they kinda got lost in the weeds.

Look at the plot... this is sort of what you can expect, although the coil was loaded down too much when I took this measurement. If you overload the coil, all you're doing is wasting the small amount of power you have available, to heat the coil.

<a href=" http://s36.photobucket.com/albums/e20/novakarl/Puch%20light%20coils/?action=view&current=HPI6V5W.jpg" ; target="_blank"><img src=" http://i36.photobucket.com/albums/e20/novakarl/Puch%20light%20coils/HPI6V5W.jpg" ; border="0" alt="HPI 6V5W Bulb"></a>

The coil can be rewound, there is space around the coil to wind for more power. Another limiting factor is the weak magnets in the HPI rotor. The core of the lighting coil is nowhere near saturated.

Re: Rewinding HPI light coil and/or replacing it.

Can you post a few pictures of the coil so i can get an idea for the coil fill and wire size?

Re: Rewinding HPI light coil and/or replacing it.

Re: Rewinding HPI light coil and/or replacing it.

Thanks! It looks like you could almost double the wire width on this setup. It also looks like a stock A35 lighting coil may fit the setup!

Re: Rewinding HPI light coil and/or replacing it.

I'd like to see what an A35 coil looks like :D

Re: Rewinding HPI light coil and/or replacing it.

Here is a link to the A35 magneto from the mopedjunkyard.com. If the bolts match up it should fit and work. Its an 80W coil but with the weaker magnet maybe 30?

Re: Rewinding HPI light coil and/or replacing it.

Re: Rewinding HPI light coil and/or replacing it.

Does anyone have a tomos A35 light coil or an old stator to measure it? Need mainly the distance between the mounting bolts. That would be pretty awesome if it was a direct bolton!

Re: Rewinding HPI light coil and/or replacing it.

Instead of replacing/rewinding the coil, why not replace your bulbs with led's? Check out this site- http://www.superbrightleds.com They claim that they have "drop in" replacements. The specs on these seem to be well within the range of the HPI coil. The brightest offered is a 5 watt unit leaving 5 watts for the other 3 bulbs that leave plenty of unused wattage (all of their bulbs except the 1w and 5w operate at 200mA or lower). All of their units come in a variety of colors. They come in your choice of 1156 (puch style single contact) and 1157 (dual contact tail light style) sockets (as well as blade and 67 & 68 sockets), they also have BA-7's (the puch speedo light socket). I have not seen any posts about this website (other than the reviews on other sites- they all are thumbs up). I ordered a set of four led's to replace all the bulbs on my maxi. I am case matching my motor and adding the HPI CDI (with HPI light coil) and a different exhaust. When I finish my rebuild and up grades I will post a thread about my results on these replacements. From what I've seen, this may be the golden cure for the HPI coil woes.

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