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DC Regulator/Rectifier mystery

My900ss said:
I am of the opinion you are over thinking the issue. You want to have a dual voltage system no? I.E. power the headlight with A/C and the turn signals, break lights and some accessories such as a heated vest or GPS with DC voltage correct?

To do so you will need both an A/C voltage regulator and a DC voltage rectifier / regulator. Now from what I read your system is not working correctly in either the D/C or A/C mode. The only configuration that is partially working is the unregulated A/C mode?

If that is correct let us agree that an A/C regulator does not amplify the A/C signal. So if you only have 10vac coming out of the regulator there is a chance you only have 10vac on the input of the regulator which would be the output of your alternator being to low.

The charging circuit on your bike, which is the unregulated alternator output should generate 13.7 to 15.3vac. The regulated A/C should be 13.5 to 14.5. You have a 3 coil alternator. Exciter, lighting and pulse generator, a basic check on these is with resistance. The exciter should measure 230 - 320ohms, the lighting 0.44 to 0.6 ohms and the pulse generator from 360 to 440 ohms.

So before you get into building your own rectifier/regulators lets start with the basics. With the wiring as close to stock as you can get it at this time are you getting >13.2 vac out of the a/c regulator? If no, are you getting >13.5vac at the input of the a/c regulator. If no are your resistance reading in spec?

Run through these checks, let us know what you get and we can try to help further from there.

For reference I own an 93 XR600R and I stayed at a Holiday in Express a few different times.
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Cool..Thanks for the input

Eventually.. if I make this bike my only bike.. I'll add the DC.. I had put in another motor and harness last weekend and tried to hook up everything cause it was already there.. For what I'm doing though.. AC works just peachy.
 
If you just wanna run that LED taillight off of it, you could use a small rectifying bridge, some small filter caps, and a 7812 or similar linear regulator + TO-220 heatsink (total cost about $10) presuming it draws no more than 1.5A or so.

That doesn't give you anything to charge a battery, but you could install it in the tail and it'd let you run a DC LED taillight off your existing AC lighting-only system.
 
Marlowe said:
If you just wanna run that LED taillight off of it, you could use a small rectifying bridge, some small filter caps, and a 7812 or similar linear regulator + TO-220 heatsink (total cost about $10) presuming it draws no more than 1.5A or so.

That doesn't give you anything to charge a battery, but you could install it in the tail and it'd let you run a DC LED taillight off your existing AC lighting-only system.
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Dude, you're awesome.. this is just a little bit information overload right now tho.. i won't loose this thread, this is good info.

I'm riding Sheet iron this weekend.. the 11th of june is the Cal24.. I'm trying to put together a flat tracker and at least get it on the track once before red sticker/enduro season starts back up and then torture myself all through that. So you can see.. I just want a stock functioning motorcycle that I can keep running..

The enduros; they're my weight loss program for men.. Dubbed it.. "Johnny Craig".. :laughing
 
Sec, I'll give you a picture of a 10V regulator I added to a surplus wall-wart the other day when I needed a 9-10V supply for a project.

This is a little overkill, I included the RF choke because it's a radio-related project, that will see some RF exposure, but otherwise it's got the filter caps, heatsink, and regulator. The one thing it doesn't have that you'd need, is the rectifier. You'd also want to upsize the filter caps a bit, to handle the increased ripple from the output of the bridge.

I'll see if I can find a schematic for you somewhere, or whip one off quickly.

So, skip the RF choke, rectify the AC into DC, the filter caps should even the ripple out into more or less pure DC, and the 7812 will cut it to +12VDC (and it should handle up to +35VDC or so, so anything your stator is likely to put out.)

The insulator between the regulator and heatsink is mica, but can be omitted if the heatsink is never going to contact any metal in the bike.

Since this was designed for a wall-wart with some existing filter caps, but still tons of ripple, I only used 470 uF caps. You might want to use something a bit bigger -- 680-1000 uF, but like this, a pair of them. The heatsink actually came from a parts bin at Al Lasher's on University in Berkeley, you should be able to get everything you need there.:
 

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Here you go:

http://www.repairfaq.org/sam/samschem.htm#schslp0

http://www.repairfaq.org/sam/samschem.htm#schslp1

Same idea, except you're taking 18VAC or so off your bike's supply, rather than an AC wall-wart, rectifying it (first link) and then regulating it (second.)

You can probably omit the resistors and use a 7812 instead of the 317...the 7812 is a fixed +12VDC regulator. There's also a +15VDC (7815) out there, but only use those if you know you have at least 20VDC available (there's some loss in the regulator, so use the 7812 if you're expecting a minimum of 14-15VDC out of the bridge, and no more than 35.)
 
I was talking to a friend of mine about this today, and he actually mentioned there's an adjustable regulator kit out there. If the drain is under 1A or so (although the regulator used should handle 1.5), you could try one of these and set the regulation point around 14V:

http://www.vakits.com/product_info.php?cPath=44&products_id=1207

Looking at the board layout, and specs, they include the rectifying bridge, so you can plop the bike's AC on one end and get up to 1A out the other.

You'll still need a good heatsink, esp. if the draw is around 1-1.5A (15W or so on the LED taillight). And you have to put it together, but it's like 6 components, soo... you should be able to handle it easily. :)

And thanks Skeeter, good to know someone is collecting vendor info around here. :thumbup
 
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Hope it helps, sounds like you have a new project...but I'm betting that LED taillight is in the 12-15W range, so you can probably just power it off a small reg/rec you've built, and leave the rest of the bike AC.
 
Marlowe said:
Hope it helps, sounds like you have a new project...but I'm betting that LED taillight is in the 12-15W range, so you can probably just power it off a small reg/rec you've built, and leave the rest of the bike AC.
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it actually works just peachy on AC.. you know what's weird? It changes from red while on ac to white when I put it on DC. ?? Weirdness..
 
Many LED lights actually have a switching converter in them, to step it up to the 35-50VDC they use...those just care that they have enough electrons (in the right direction) -- as long as the converter's bucket gets filled it doesn't care what's in it.

And that's odd...unless these are bi-color LEDs, designed to change color when you reduce polarity.
 
Marlowe said:
Many LED lights actually have a switching converter in them, to step it up to the 35-50VDC they use...those just care that they have enough electrons (in the right direction) -- as long as the converter's bucket gets filled it doesn't care what's in it.

And that's odd...unless these are bi-color LEDs, designed to change color when you reduce polarity.
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Sunspots? It was running off a 12vdc battery, it's white.. 12vac it's red. weird? Yeah.. fer sher..
 
Remember this is BD, and the kit is for lighting a dirtbike. You won't get enough of anything to power a Reg/Rec.

If that's what you really want, I think it would be easier to have a stator made, and install/hack together a new electrical harness.
 
And if you're looking for better lighting, seriously consider HID as you'll get 3+ times the light compared to a standard 55 watt halogen and you'll only draw 35 watts. Great for bikes with marginal charging systems.
 
ST Guy said:
And if you're looking for better lighting, seriously consider HID as you'll get 3+ times the light compared to a standard 55 watt halogen and you'll only draw 35 watts. Great for bikes with marginal charging systems.
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:laughing You guys crack me up. I appreciate the candor though.

If you didn't know.. this is a very well used and throughly abused 1986 motorcycle..

It has more used parts than a Chicago Taxi cab and it looks just as bad.

The only thing I buy new for this bike is consumables.. If I found a used HID system, I'd put it in the parts bin and wait for the next bike to install it on..

Really what I'm trying to say is this bike is not worthy of HID.. :laughing
 
You'd think that, but HID kits are now getting cheaper than replacement high-quality halogen bulbs.

I'm not kidding. German-import halogen bulbs costing me more than HID kits with ballast.

:laughing

But I do understand the spirit of the build ;)
 
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