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Judah Gardner

48v To Power 9-36v Lights

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Hi. I am wrapping a lighting coil for my xr 100, and SoCal XRs site said it would output 48 volts max. Now would this be enough to ruin my 9v-36v led lights? And where would I find a 50v max input 12v DC voltage regulator?

Edited by Judah Gardner

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48volts is the no load voltage. When there is a load like lights the voltage drops.

The alternator produces AC voltage. LED lights require DC so you need a regulator/rectifier to convert the AC to DC and regulate it 12 volts, plus a filter (battery or capacitor).

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I have a 12 volt battery but if hook it up to the stator will it ruin the battery? I have a rectifier which is rated 35 amps and 800 volts. The stator is 14v on idle but it gets to 48 on Max rpms. I read that if you charge a battery on to high voltage it will explode. So hooking up the lights will cause the voltage to drop because of load? How far can it drop?

 

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I really like the TT reg/rec.  The timed output wire is perfect for running lights and such because it automatically turns off the power for you so you don't risk running down the battery.

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Would the part in the link I posted possibly work? The one you posted is a little pricy. And would running the lights without the regulator be fine till I get the part?

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In theory you should be able to use an AC voltage regulator, and then run it through the rectifier you have to the battery.

AC regulators are quite a bit cheaper than the reg/rec.  TT makes one that isn't very expensive.

I tried to get this type of system to work on my '82 xr200r, but never really got it to work.  That old xr had a really weak lighting coil that could have been part of my problem.

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35 minutes ago, Judah Gardner said:

Would the part in the link I posted possibly work? The one you posted is a little pricy. And would running the lights without the regulator be fine till I get the part?

Won't work 'cause it's for floated ground stators (2 wires full wave).

Your stator needs a (1 wire half wave) kokusan reg/rec like this: https://macht-shop.de/shop/spannungsregler-gleichrichter-12-volt-kokusan/

That's because you built a grounded stator what would produce about 50W at regulatet 12V output.

Or you feed out your stator windings (the beginning and the ending not touching any ground) with two wires, so you will get a floated ground stator with an output about 100W regulatet. Than you may use the railtech 150 reg/rec.

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Just looked at the part you linked and it looks like a spare part I got from a Chinese quad. I’ll go test it to see if it’s the same

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Most DC charging system use a floating ground alternator with 2 wires out but you can also rectify an internally grounded alternator  with one wire out.  I've done that on early XRs.  For Hondas 2 wires out are usually a yellow and a pink, one wire out are usually a blue.   The wire counts mentioned do not include the wire that powers the CDI ignition, usually a black/red wire.

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Yes, I’ve just been messing with an XL alternator. There are 3 different coils: 

1. Primary magneto (blk/wt stripe)

2. One-wire AC headlight (blue)

3. Two-wire AC to reg/rect (pink, yellow)

A Moose two-wire regulator will work with the half-wave headlight coil. The old XR/XL bikes were 6V but will easily run 12V.

81AECFBD-6895-4462-AB36-D7A94DDBA1A3.jpeg

Edited by FightingRed

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