rectifier / floating ground ? (ac to dc howto)

[henrys]

I got this idea from 'buzztail' on the advrider KDX thread. With no modifications to the oem stator you can rectify the stock half-wave AC signal to DC for an LED headlight (leaving the rest of the system AC). Since the LED headlight uses much less current there will be enough left over power to run a brake light without having to float the ground on the stator.

Wiring diagram:



Rectifier/capacitor



Components used:

H6M LED headlight
AC to DC rectifier
10K uF capacitor
Mechanical brake light switch

I also swapped the rear bulb socket for an 1157 and wired the brake light circuit through the switch. So far its working like a champ on the factory stator.

[bufftester]

If all you need is an LED headlight this will work fine, or you could just run the LED on the stock wiring without any rectifier. But if you're trying to make it street legal many states also require turn signals, hi/lo, and a horn which will quickly overtax the stock stator. Pick the setup that fits your needs.

[spl383]

I got this idea from 'buzztail' on the advrider KDX thread. With no modifications to the oem stator you can rectify the stock half-wave AC signal to DC for an LED headlight (leaving the rest of the system AC). Since the LED headlight uses much less current there will be enough left over power to run a brake light without having to float the ground on the stator.

Wiring diagram:



Rectifier/capacitor



Components used:

H6M LED headlight
AC to DC rectifier
10K uF capacitor
Mechanical brake light switch

I also swapped the rear bulb socket for an 1157 and wired the brake light circuit through the switch. So far its working like a champ on the factory stator.

Can you please repost the wiring diagram
Thanks

[henrys]

Can you please repost the wiring diagram
Thanks

It's still loading for me but I added a direct link to it from the "wiring diagram" text. If you're still having trouble shoot me PM and I can email it to you.

[TexasTom]

Hi henrys, I'd be interested in the wiring diagram please :-) (I can't PM you not sure why?)

working on making my KDX street legal ;-)

[SS109]

(I can't PM you not sure why?)

PM's are only available to supporting members. It's one of the benefits we use as a perk for members to donate and keep the forum up and running yet ad free.

[TexasTom]

@ss109, when I click on donate it, brings me to https://ipnpb.paypal.com/donate/ but the page doesn't work.

[Julien D]

@ss109, when I click on donate it, brings me to https://ipnpb.paypal.com/donate/ but the page doesn't work.

We have issues with the integration from time to time. It seems to be on paypal's side. You can always just send a PayPal payment to admin@kdxrider.net and include your kdxrider username in the message area.

[Whip!]

Rectifier?! Damn near killedified 'er!
No really though. Thanks to Bufftester for those wonderful drawings. they got me where I needed to go.

[billie_morini]

questions:
where is the rectifier to be added? (please be specific)

See below

is floating the ground simply removing the grounded side of the lighting circuit and connecting it to one of the ac leads on the rectifier, then the yellow ac wire to the other ac lead?

Yes

is the dc +/- just connected to the lights (with a fuse) or should it go through the regulator?

Yes. Normally a rectifier also has the regulator built in, you don't reuse the stock regulator

draw a picture if you like. simpler is better.

Start here
KDX wiring1.jpg

Take out everything circled in green
KDX wiring2.jpg

To end up here. At this point all you have is the ignition circuit.
KDX wiring3.jpg

Add rectifier/regulator and battery (you have to figure out the actual physical mounting locations, but plenty of posts on here about that)
KDX wiring4.jpg

Add new wiring. Note that this is where you "Float the ground" which just means you run the side of the lighting coil that was connected to the case to the new rectifier instead
KDX wiring5.jpg

Et voila you are done!. Keep in mind that at this point you are now running your lighting on a DC circuit, so anything you add has to be connected back to the battery + and -, not the frame. To help make the 2 circuits easier to visualize, above the blue line is ignition, below is lighting.

THANK YOU, Bufftester! I've been wondering exactly how to do this. Your notes & diagrams are thorough enough that I can now do this.

[Nickgindy]

I am late to the game. Anyway to rewake this thread and get the diagram posted again?

[bufftester]

Page One has all the drawings

[Chuck78]

Also, this kit is a nearly direct fit for OEM KDX headlights 1990-2006 (excludes 1989, different bulb socket iirc):

https://www.cyclopsadventuresports.com/ ... b-kit.html

It's got an inline rectifier, so no need to pull the flywheel if the stock stator output is sufficient. I would downsize the taillight bulb to something dim or run it post-rectifier also with a splice into the Cyclops pigtails. It just needs a post-regulator positive feed + ground, and wired through the switch or use their provided Trail Tech high/low/kill switch (or can be used for a horn vs kill switch but that'll require more statpr and preferably a battery)

Honda XR use the same light bulb socket for the headlight.

Yamaha WR's use the same taillight as a KDX aside from them having a dual filament socket for an 1157 bulb also, FYI!

[Nectarius]

Hello, I'm posting my question here because it's a similar topic. I've had a 1992 KDX 250 for a few days now. It has an incomplete electrical system, and today I tried to complete it to activate the lights.

I don't understand much about this, but I built it exactly as shown in the diagram below, and when I turned on the light, it blew. One possibility is that I have a faulty regulator, but looking at the diagram, there's one thing I don't quite understand. Why does the regulator only have two connections? Isn't it supposed to have one input and one output? AC-DC.

Looking at the diagram, I connected the yellow wire from the magneto to the light switch and from the light switch. I connected two wires, one to the front light and the other to the regulator and taillight.

My question is, what does the regulator do here? If the headlight receives power from the magneto before passing through the regulator,

I hope I've expressed myself clearly. I apologize, thank you.

[Chuck78]

Shunt type regulators simply bleed off excess voltage directly to ground at a high frequency, dozens of cycles per second of switching on and off, short circuiting the extra voltage to ground, which basically leaves your charging system always working at full output even if there is minimal or no load.
A series type regulator will rapidly cycle the disconnecting and reconnecting of the power coming from the state or at a high frequency, 60 or 100+ cycles per second.
We have shunt type regulators. They just bleed off excess voltage to ground.

[bufftester]

As Chuck said, we have shunt regulators, and it's A/C not D/C. Using a multimeter start the bike and set the multimeter to AC Volts. Measure at the output of the regulator and at idle you should see around 10-11 volts AC, at higher RPM it should go up to around 13V, but no higher. If the regulator is bad you could see it run up to 15+ volts AC which would blow out your light. Very important to make sure your grounds are clean and connected to the right terminals for it all to work.

[Nectarius]

Perfect !! I m undestand ... Thanks for expication.