Parallel Stator Rewind?

Hi,

I'm thinking of rewinding my stator also. I did some searching on the board and nothing about "parallel rewinding". I think this could be more efficient circuit. It will be less heat for the regulator to dissipate (or wasted) because of stator running at high voltage at high revolution. I'm trying to stay close to 12 to 18 volts with more current on tap.

Thanks

Hello,

I just rewound my stator on my XR250. I have yet to try my mod.

My understanding of generation (as it was explained to me by my older brother who professionally designs and tests mega-watt power genrating facilities), is that the voltage is proportional to the number of winds/wraps of wire, and power generating capacity is proportional to the "amount" of wire (or gauge).

In my system, I maintianed the approx. same number of total wraps (I beleive there was 300 wraps across four poles), but I used heavier gauge wire. The heavier gauge wire neccesitated that I use the two unused poles of the stator (for a total of six).

It's also important to increase the guage of all of the wire (i.e., you shouldn't simply use thick wire on the two new poles, and continue to use the OEM thinner gauge wire on the first four poles).

I actually did increase my total windings somewhat just to provide slightly greater voltage.

I'll let you know if this "theory" is correct. :)

Regards.

Dale

Xr guys

regulator to dissipate (or wasted) because of stator running at high voltage at high revolution. I'm trying to stay close to 12 to 18 volts with more current on tap.

I'm not so sure any increase in voltage is going to be a waste, voltage multiplied by current is watts.

A alternator will be limited by the ability to transfer current by its wire size and magnet size.The fact than you want to parallel 2 wires is fine but a single winding will not be a waste either.The regulator needs a higher voltage to "clamp" down the voltage to the proper level. If it sees lower voltage that its designed for then poor regulation is achieved.

To keep on track with your question the "core" which we can call the heart of the alternator has a specific ability to "make power" , weather the voltage comming out is 50v or 12v it cannot make more wattage than the magnetic field is able to transfer from one pole to another.

I rewound my xr250 a few yrs ago, the very most i got from adding 2 extra coils was 85w total output, this is measured with a load after the regulator, on the xr600 more empty coils are available 6 i believe and the recipe is the same, bigger core gives you more wattage out.

If you add the prescribed amount of wire which in my case was 30 windings per coil it will increase the wattage by the proportional amount.Voltage also increased

Its quite easy to do and is simple enough to measure the results. Check on this forum , others have posted their results , with great success.

I have been building high voltage supplies for the past 20 yrs and have found that you can exceed the ratings on any given product by a good 20% weather it would be current or voltage, the same idea can be applied to our type of alternator, before it has a meltdown its going to take some doing!

good luck

I forgot to mention it for my xr400r (2002). I assumed I have 6 pole available to use to add some watts/power. I'm still not clear when you guys say, "voltage is proportional to the number of winds/wraps of wire". Does it mean that for every turn/warp=1 volt? is this true for any RPM? is this also the same case for current=1amp?

the non scientific way before you start anything is to measure what voltage and current draw you have now. You need 2 meters for that, one measuring volts other amps.

Say you have stock headlight and rear taillight, the front draws abt 35w and the rear light maybe 10 w, measure the voltage under this load..

Then you can open the stator and have a look what you have in terms of available spools to wind.

Have a look at the article which some of us based our windings on.

Weather it was xr or ttr's or whatever they are basically the same idea.

http://www.thumpertalk.com/forum/showflat.php?Cat=0&Board=UBB26&Number=665675&Forum=UBB26&Words=stator%20rewind&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=6months&Main=663096&Search=true#Post665675

I'm not sure weather this link will work , but do a search in the past 6 months on this BB for stator rewind, this is a very well explained session , you will also see the pic of my stator on there.

Burnrider did a bang up job documenting his efforts, , my rewind was done before joining TT so i never really documented anything

stu

I used the parallel 20awg setup I found on the Yahoo XR650R group and it runs a 100W H3 bulb and taillight with only very slight dimming at idle.

You can check my link for photos. I powered 2 - 35 watt bulbs and the tail light with very little dimming. That's only 75 watts. My goal was to use the headlight, tail light and grip heaters at the same time. There is plenty of juice for that. XR250rdr sounds like he got a lot of power out of his 20 ga wind. I don't honestly know what my limit is.

It works much better than I expected. The description said about 80 usable watts. Since my bike didnt come with a voltage regulator, I figured a 100W bulb should keep the voltage down and I would just have to deal with dimming at idle. I was in for a rude awakening when the 100W bulb burnt out about 15 seconds with the bike idling.

I used the parallel 20awg setup I found on the Yahoo XR650R group and it runs a 100W H3 bulb and taillight with only very slight dimming at idle.

I have been gearing up to rewind the stator on my XR4, and I like the idea of the parallel coil setup, but I have a few questions about the parallel setup.

The parallel stator rewinding how-to's I have read about usually have one "side" or coil powering the headlight, and the other coil powering everything else, but I have not seen any detailed pics of how the 4 wires from the 2 separate coils are terminated on the stator and connected to the wiring harness to establish the 2 separate power sources.

None of the aforementioned how-to's mention anything about using separate voltage regulators or regulator/rectifiers for each "side" of the parallel setup - if you run both coils through one regulator or regulator/rectifier, don't you lose the whole reason for using a parallel coil setup? Just run with a single coil setup then?

I am assuming that the benefit of a separate coil on a parallel setup dedicated to the headlight would eliminate the dimming that is usually associated with a "conventional" setup when brakes are applied, heated grips turned on, turn signals used, etc. That, and to keep a single regulator/rectifier from having to deal with 200w all the time in a single coil setup.

I plan on running a 55/60w headlight, an 1157 tail/brake light (10/25w), grip heaters (33w on high setting), a DC horn (20w), a license plate light (10w), and power for a GPS (guessing 2 watts max). I would like to have the wattage on reserve to add turn signals (10 or 20w?)if Johnny Law says I need to add them down the road. Another 10% wattage in reserve on top of that wouldn't hurt either. That puts me somewhere in the 170-190 watt range.

Thanks in advance for any info provided!!

You dont lose all the advantages. You still are acheiving lower resistance and thus less wasted power.

Its hard to explain how I hooked the coils up without drawing a diagram and I cant do it with this laptop touchpad.

Fabricator

If you want all those lights and accessories then you might concider a couple of these options.

If you are carefull in selecting 1157 and get LED sprinner type , they are as bright and consume much less power, i saw them at a truck stop they are just a bit bigger than an 1157 and pretty bright indeed.

Another solution for BRIGHT lights is the igniter type of units which are found on BMW's and other fancy vehicles they draw practically nothing but put light as if it were day!, these are often found on ebay for less than $100.Baja desigh had these HID type of lights but are quite costly.

If you are looking for good regulation i may suggest to put a 12v 4ah battery under the gas tank or nicads or Nimh batteries, this will take care of any "blinking/dimming" in your circuit, it will be very difficult to keep regulation with varying loads,(flashers) the battery will act like a capacitor and smooth out the variations.

The regulator on the Xr will have to be changed since its AC , going to a DC regulator will permit you to use a battery for regulation or reserve.Some mentioned a brand which i'm not familiar with , the one i bought is from a snowmobile its from Kimpex, it seems fine , it was something like $45.00.

A guy i know does conversions and uses the battery packs from Baja are a small tube like affair with 4 c cells , so a battery pack can be made by using the same idea.

You annswer to regulator with your winding which you want to use, apply this rule KISS, keep it simple and stupid, in designing power supplies its often easy to go overbord with protective ckts, the problem with that is farther down the road when you have a problem , you have too many variables.

One regulator with ac to dc converting will suffice, these regulators are not very fancy in design, and whatever you do put a fuse before the regulator, and possibly on the grip heaters , the lights are seldom a problem, grip elements connecting wires come loose and short out sometimes buring the hell out of the wire if not fused.

None of the aforementioned how-to's mention anything about using separate voltage regulators or regulator/rectifiers for each "side" of the parallel setup - if you run both coils through one regulator or regulator/rectifier, don't you lose the whole reason for using a parallel coil setup? Just run with a single coil setup then?

Not necessarily, the // windings are giving you more current not voltage, it however do able to do as you suggest and have 2 outputs from your stator, personally I could not see the advantage , as i mentioned before , the magnets and stator can develop X amount of watts, so weather you decide to to series or // windings , the alternator will peak out at max wattage out.

Weather one is more efficient than the other , its hard to say.

It is a good idea though in theory.

I am assuming that the benefit of a separate coil on a parallel setup dedicated to the headlight would eliminate the dimming that is usually associated with a "conventional" setup when brakes are applied, heated grips turned on, turn signals used, etc. That, and to keep a single regulator/rectifier from having to deal with 200w all the time in a single coil setup.

As i mentioned , i'm into power supply designs, here's my take ,

Dimming is poor regulation, again without getting into too much detail, here's an example , a power supply is rated at say 12v @ 1/2amp DC, the designer uses a 3/4 amp transformer,so that he may benefit from the AC regulation in designing a given supply without the expense of additional components .

By going with a bigger "unit" we can achieve regulation , but when the bigger unit gets to the speced output values of a given device regulation suffers.

What we are doing by winding our stators is exactly this..

I hope my analogy helps .

stu

Thanks for the feedback guys,

If you want all those lights and accessories then you might concider a couple of these options.

If you are carefull in selecting 1157 and get LED sprinner type , they are as bright and consume much less power

The LED spinners I saw looked like the cluster of LED's is a lot larger in diameter than the glass on an 1157 bulb?? Will the LED spinner fit in the stock XR tail light?

If you are looking for good regulation i may suggest to put a 12v 4ah battery under the gas tank or nicads or Nimh batteries, this will take care of any "blinking/dimming" in your circuit

I forgot to add that in my long post - I think a battery in the system will be easier on a GPS unit too(?).

A guy i know does conversions and uses the battery packs from Baja are a small tube like affair with 4 c cells , so a battery pack can be made by using the same idea.

I was looking into making my own battery pack as I have soldered up RC packs in the past. 4 C cells? I was looking at using 10 AA's (pack configuration yet TBD).

...easy to go overbord with protective ckts, the problem with that is farther down the road when you have a problem , you have too many variables.

...put a fuse before the regulator, and possibly on the grip heaters

Good point on the KISS aspect. Was planning on a fuse for the grip heaters, but adding a main fuse should have been obvious - good idea.

Dimming is poor regulation

Understood - I guess it sounds like my biggest concern with my mods is possible dimming, and it is not. If I wanted to stay away from that, I guess I should have gotten an XRL or a DRS!! :D :D

I hope my analogy helps

You bet!! :):D Thanks again!

Fabricator,

as for the leds , here's an idea for you, although it wont be as clean looking each led will work from 1.5 to 3 v each depending on how long you want them to last , they can be hooked up in series if you connect 4 or 6 in series it will handle the 12 volts no problem.

they are about 10 cents each so you could experiment, keep in mind they have to have DC to work.( you can toss a single diode in the line , that will be fine , the beauty of leds they draw .010amps each.

I use a gps but prefer using Nimh batteries, the etrex i have will run for about 16 hours without problems .

The gps will like to see good regulation you sort of have to run the cigar lighter guizmo which comes with it. As an example the etrex needs 3v so there is plenty of regulation .

Ok on the nicads , AA 's in series , Its going to be hard to get oumph out of AA's unless you get newer types of cells. The battery i bought is 4"long 2x2" give or take its 4 amp hour at 12v, which means if your stuck in the dark off the road with a dead engine your good for headlight say 50W for close to an hour , you will never get that with AA's .

Have a look on ebay under nicads , the specs are often listed there , it will give you a real good idea what loads they can handle. Some batteries are excellent some are very poor.

stu

L.E.D.'s will work in AC circuits - they'll just illuminate on the positive cycle and thus may not be as bright as with a DC circuit. While the AC frequency of a motorcycle alternator is quite high, a good portion of the waveform is below what a DC circuit would give. I have not seen the light output of an L.E.D. on a motorcycle AC circuit so I don't know how much difference in light intensity there acutally is.

There is no reason to put a diode in series of an L.E.D. as was stated earlier - an L.E.D. is a diode (that's what the "D" stands for) although it will add a voltage drop of ~0.7V.

Since each cell in a rechargeable battery (lead acid, NiCd, etc.) is about 1.2 volts, the four C cells stated a few posts above will only produce just under 5 volts. That might be fine to run independent of the headlight, etc., but if your goal is to have a 12VDC system, you'll need 10 cells producing 12.0 volts.

Stuart

re the C cells , there were 2 packs of 4 cells per tube, I omited that part!,

as for the leds you're right that will work too.

stu

Thanks for all the info guys!!

Gotta order up the gasket for the alternator cover and get to work! :)

I'm looking into rewinding my stator as soon as my (well soon to be my xr400) gets plates. My question comes from observations I have made about battery chargers and automotive alternators. Dont these operate at slightly higher voltages than the output of the battery? So in the case of a 12v battery, shouldn't the voltage regulator be allowing somewhere around 15v? Will the light bulbs handle 15v rather than 12v? How about HID? If 15v is where its at, can a stator wound in parallel provide a minimum of 15v continuously?

Also, has anyone built their own regulator/rectifier? Seems pretty simple from what I have read across the internet... bridge rectifier, voltage regulator, zener diode, and a handful of capacitors to even things out. http://www.numbskull.com/snowmo/gps/schematic.asp

Very interested in doing this myself, as I would rather understand this myself rather than pay someone else to understand it.

MHR

I rewound my xr400 myself last year and have had no trouble in 1600 miles.. I left the stock windings alone and they are still plugged in to the stock regulator and power (AC power) one light (50 watt bulb). I rewound the remaining poles separately and the two wire ends come out of the case next to the stocke wires. I have these two wires hooked up to the Baja Designs regulator/rectifier (DC power) and they power the headlight, tailight, battery, etc. I get about 125 watts out of the rewound side at high rpm. I just wound as many winds as possible on each pole but remember that when you finish one pole you have to wind the one right next to it so leave enough space between them to wind the same amount on it.

I really want to rewind my stator too but am alittle nervous about messing up the electrical system. Can I rewind the stator and not burnout bulbs? I just want a brighter head light.

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