DC headlight power?

With 55 watts AC power at the front headlight, has anybody tried a rectifier at the headlight plug in? I am looking at this for a power source for a HID light. The HID needs 35 watts DC power to run so why not use this as the solution. This way the battery still charges and lights are bright. Ideas?

why not abandon your ac power and just run a new line to your battery to get dc power?

i thought they are dc power to the headlight, it is a 12v h4 bulb

why not abandon your ac power and just run a new line to your battery to get dc power?

This would be easier, however the potential for running down the battery with its minimal charging system would be much greater.

on the 05 and 06's they have a seperate feed for the headlight then charges the battery, the there are two parts to the charging circuit, I have heard the headlight part was ac and others say it's dc, I never checked but rewired mine to make one large charge circuit to charge my battery which the headlight now runs off.

The headlight is AC, it uses its own coil at the flywheel to just run the lights. Problem with rectifying it with a half wave rectifier, is you will have a moment of no voltage, and even if you did a full wave rectifier, still be a moment of zero voltage, just not as much. Visualize an AC sine wave (looks like a slow rolling wave) and now draw a line horizontally in the middle (cross section). Now anything above the line would be voltage you'd see with a half wave rectifier, anything below the line is chopped off. So it would be about a 50% on, 50% off. Of course, you wouldnt see it, just a dim light. Now a full wave rectifier would "flip" the bottom part of the sine wave over so now it would look like (sine wave) the rounded fins on the back of a stegasaurus and the valley would be a second of no power, but might work out. A rectifier will itself, consume energy and dissapate it in the form of heat. So you will have DC, but with some loss. And I think the lighting coil is made just large enough to run your headlamp, which is 35 watts, both low and high beam. Maybe consider having it rewould? It can be upped, but drawback, its unregulated and if it can produce more, it will with more RPM's and could shorten bulb life. So a regulator might be in order also. A full wave rectifier will look like a square with 4 blade connectors on it. 2 blades on opposite corners will be marked AC and AC, hook your existing wires bulb wires to these, and then hook the other 2 blades on the opposite corners to the bulb itself. Those other blades will be marked + and -. For a half wave rectification, just solder a diode inline on one side only, striped end wont matter, unless you care about polatiry, then the striped end of the diode pointing towards the bulb would be the positive. Does this make sense to you? Do a search for full wave rectifiers also. But a rectifier better be rated enough, ie 35 watts. Hooking a pair of diodes in parallel will double their rating, but they MUST be pointing the same direction, ie stripped end or anode and cathode

Well I have tried several rectifiers with no luck. The wires get hot and the HID wont turn on. The voltmeter reads 7 volts DC with no load, and the AC was at over 12 volts. I think the AC lighting coils are just to light for good DC output. I have wired the HID direct to the battery, which should give me around 2 hours of running time. So would it be possible to run the AC headlight power into the WR voltage regulator and increase the output to the battery? Right now the HID consumes more power than the bike makes stock. I may go back to the stock headlight as it is simple and dependable. With the aftermarket bulb and a helmet light it does a great job now that I can compare lights.

the stock head light is wired only for low beam,

get a regular old car headlight plug, get a 3 way toggle switch, put the hot wire to the center of this toggle, then a short whip of wire from the toggles other posts to the car plug wires, take the car plug ground to the stock ground of the bike, mount the toggle where ever you like, i mounted mine just to the left of the headlight out of harms way, vola hi beam low beam,

plus a helmet light, i am currently running a middle of the road h4 blue tint (cool factor) 55w 100W, seams to work fine, i see PIAA makes a bulb that only draws 55 w and is equivlent to 135w or something like that, i will try that next,

so far this set up lets my ride anywhere with no problems

Trail-tech makes a rewound stator and a rectifier that makes enough DC for everthing you need.

It was made for the YFZ Quad, but it fits our WR450F´s


I have just installed such in my bike and am running a 8" HID 35W

The trailtech kit makes about 100W but will be enhanced with their flywheel which has stronger magnets built in.


You can also check out Baja Designs website and make a mod to the oem stator but it will never be as powerful, and you will always need bigger rectifier.


the stock head light is wired only for low beam...
Actually, the stock headlamp on a WR is running high beam. So you will need to add the low beam if you want to use both elements. I have done this with great results using the K&S dual sport headlamp switch. It was detailed in this forum some time back.

See it at think link I found in the search section of this forum

Read just about everything in the forum on WR lighting for dual sport. Seems to be 2 different objectives. Legality and seeing at night. I am going to use the KS switch to hooked up to the battery for the highway patrol check and then hook the tailight and headlight back up to the AC. Keep the turn signals, horn and Vapor speedo on the battery so as to not overload the stator with the headlight, tailight and stop lamp on while slowing down. Of course, I don't ride that much at night preferring to party around the campfire when the sun goes down. If I need night light I use a helmet mounted lamp with a 6 volt krypton bulb powered by 4 D-cells. Good for 2+ hours of continuous riding and easily as bright as my headlamp. Dune riding anyone?

As noted, the WR has two stator outputs. One is for AC and one for DC. We made a WR specific stator that has single DC output (good for 100 watts at idle):


It is plug and play. Here it is on an 07 WR:


The Baja designs modded stock stator (an easy mod) takes both the outputs both ac and dc and turns it all into dc which people say is still 125 wats total but it tall goes through the battery now as does the headlight, it works well here......Never a dead battery since i done the mod


There is NO WAY you will get 125 watts DC power from any mod of the stock stator. Look at the picture above. Note the thicker-than-stock magnet wire? The thicker wire allows higher current. With a single 16 awg output, you will get about double what a stock modified stator can put out.

The stock core uses smaller magnet wire to allow for more turns/pole (remember they are not using all the poles for each output). You need a certian number of turn before your voltage gets high enough to produce 12 volts. When you increase the number of turns by joining the outputs, you get more voltage but your current capability is not increased. More voltage is not a big help as it is shunted by your regulator.

We stopped doing modifications to the stock stator back in 04. Low output and vibration failures gave us too many problems. We only saw vibration problems on the ATV's than ran sand (lots of high rpm running). After this, we started stripping the entire core and rewinding from scratch. This did much better but the thin overmold on the OEM core eventually fails and the stator starts to short out.

In my opinion (based on test data), if you are combining two outputs into one, it does little good. You end up creating more heat and getting only minor improvements in DC capability. If your going to run a single output, run one that is optimized both in number of turns and wire awg.

Take this for what it is worth - just another post. If you want hard data, bring the machine by. We will put DC loads on the regulated/rectified stator output and tell you exactly what you can run.

Well I asked here what power it made and that was the answer I got 125 watts, I hear what youre saying, so far i have not had any problems with my battery staying charged or any power failures. Maybe i won't be able to say that next year, but thanks for sharing your input...

The myth is common. Even the OEM's rate power at red line. This is where the stator puts out the most.

I like to tell people what they can realistically expect, not what they can get of the run at red line.

If your not getting a dead battery, you have enough power. If you make too much stator power it can lead to heat problems. Your better off not running any more power than you need.

You could add stators to your website for WR's and instructions to match. I talked to the tech at Baja Design and they just keep it stock as it has all the power you need when modified. Plus your phones have been busy for two days whats up with that?

Yes, we need to add the WR stators to the web site. Our web site guy has a deep list.

We like to see ability to run a 35 watt main HID, a 30 watt HID on the helmet, E-Start and Fan. You cannot do this with modified stock.

Back in 04, we were modifying stock cores. While they worked for many, we saw too many failures. As this can leave a customer walking, we gave it up and tooled a core to do it right. We only recommend stock system modification for KTM's.

Our phones are a problem - sorry about that. We have a brand new facility that has more phones, more room, better production capabilities.... We will move in May:


Hey, I have tried calling you guys for 3 days now. I have emailed Jeff from work to call me at work. I like you guys, but I need my stator! Dont you need money to build the place in the picture? good then send me one for free! I expect to see you guys at Starvation ridge again so make me happy.

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