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Convert and combine the AC stator output to existing DC output?

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Trying to get my head around these electrical systems. My bike 14' Beta 520RS has both AC and DC output. Converting over to LED lighting and wondering if I'm already rectifying to DC for LED can I just make the entire stator output DC to the battery? Is this "floating the ground"? 

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Yeah you would want to do it that way, keeping the Battery/LED ground isolated from the frame. 

 

That way the Coil/Spark discharge won't interfere with any of the DC stuff or cause any ground loops. It won't hurt anything, its just bad practice and might make the lights oscillate in intensity.

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Thanks for the info. Most of my reading on this subject has been for dirtbike conversions that are all AC. The ground is what is throwing me.

 Looking at my bikes diagram,  the only thing that is AC is the headlight and possibly the CDI. The battery is grounded to the frame and I see no AC ground except through the load (headlight)- AC hot on one lead and frame ground on the other. The only AC return (negative?) is from the stator to the factory reg/rec.It appears this system already has the AC ground "floated" in stock form. Since the DC and AC currently share the frame ground (through the headlight), I assume this is not causing issues as it's factory wiring. 

 I figure I can grab AC hot before the headlight switch and AC return at the existing reg/rec. Then run that AC to a new bridge rectifier and capacitor  to give DC to my LED headlight. 

Clear as mud?

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If all you want to do is run an LED headlight, plenty will run on the AC, some do need it regulated and rectified. The Baja Designs light are plug N Play. Others, you will need to put a reg/rect in just before the light. A cap will reduce some of the flicker (you will still get flicker until the rev's are over 3,000 or more).

Assuming the reg/rect is isolated from ground, simply connect the two wires going to the current headlight to the reg/rect and the output to the cap and the light.

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I recently converted my Xr650r to dual sport using the stock stator and all led bulbs.

The stock configuration used ac to power both the ignition electronics and lights, using a frame ground.

I left the stator circuit powering the ignition in the stock configuration.

For lights and horn I wired that stator loop to a reg/react and to a small battery.

I tied the dc circuit to frame ground as well. So both the ac and dc circuits use the same physical medium for ground. As far as I can see there is no reason this should not work.

As it turns out, it does work very well. My xrr starts easily and runs strong. Lights and horn work fine and the battery charges.

FYI: the r/r I used was pirated from an XR650l and I’m only using one leg of the ac side of it. The ac regulator that provided power to the stock lighting circuit was discarded.

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Thanks alteet,

I haven't had time to revisit this. I wired in a cap and bridge rectifier to run the light but it didnt work. I think I need to get a good reg/rec and do like you did. 

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On my Xr650r I thought about bolting on a full wave bridge but wound up grinding the fins down on the XR650l r/r to make it fit in the space occupied by the pen part. Since the Xr650r stock stator only puts out an alleged 75W, I reckoned it would be safe to reduce r/r cooling by a slight amount.

So far, so good.

I’m not sure why your cap and bridge rect didn’t work. It should even work without the cap but you would likely see more ripple at low rpm. I’m assuming your cdi ac is a separate stator winding from the stator winding that powers the lights.

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I grounded the new negative from the bridge to the same ground wire as the headlight, which ultimately is frame ground. 

 IIRC, I took the AC headlight switch feed (did this so the switch would then feed DC for hi/low beam) and into one AC terminal of bridge. Then grounded the other AC terminal. This may be where I went wrong. 

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