100W headlight on AC or DC?

[DSTerry]

I have been reading quite a bit about rewinding stators, and how others are running their high power headlights. It seems that most people run the headlight on AC and have it always on.

The Baja Designs kit runs their headlight on the DC side. I was thinking of doing the same with the following setup.

Rewind my stator for a single high power output, 16AWG or 18AWG not sure yet. Run the heavy duty AC regulator from Ricky Stator and a 25A bridge rectifier. So if I turn my headlight off the regulator / rectifier can handle the full power of the stator. Run all lighting (100W/90W headlight, tailight, signals, horn, speedo light) from the DC side with a 1.4A SLA battery.

The advantage to this that I can see is that I will be able to switch my headlight on/off. If my engine were to stall, my 1.4A SLA battery could sustain the 100W of lighitng for about 15 seconds or so before it were to die. It has a maximum short duration discharge of 14A. This could be enough time to get me out of a tricky situation at night like going down a steep hill and stalling the bike.

Since I don't have any experience with this, and most people tend to go with the AC headlight setup. Is their any reason not to do what I am proposing?

Thanks.

[snaggleXR650]

The general reason to run it AC is because of the puny 150W rating of the combination regulator/rectifiers, and because the battery will be drained very quickly. As you mentioned, using a 250W heavy duty regulator and a ~25A bridge rectifier solves the first problem, but your battery will still be zapped quickly.

Take note, I've yet to actually try the heavy duty regulator/bridge rectifier setup, so I'm not sure of any possible problems. The rectifier is cheap, so worse case scenario you aren't out a bunch of $. However, it *should* work just fine. I've built some high current homemade power supplies that used a transformer to step down 120VAC and then a bridge rectifier to covert to DC and then ran that through a capacitor to smooth/filter the DC output. It works great, and it's doing the same thing that it would be doing on your bikes electrical system. You'll just be substituting the capacitor for a battery.

My Buell headlight has a tiny bulb that fits in the middle of the housing. It's the same as the running light bulb that comes with the Baja Designs DSK headlight. It only puts out like 10-20W or something. This is running off my battery along with the rest of the DSK system. Just my dual 55W's are running on AC.

If you are planning on 100W+ lighting you will HAVE to do the 16awg winding on all ten poles, 32-34 turns per pole, total 320-340 turns, I did 320 turns on mine. The 18awg wind won't be able to drive the lights and a DSK and charge a battery, this is more for a 55W headlight system. Also, beaware that you should upgrade the stock wiring from the stator to the regulator/rectifier and to the 100W headlight. Use a minimum of 16awg for current carrying capacity. You CAN fit the larger wiring through the rubber grommet where the wires come out of the stator cover. Good luck.

[sorenlaf]

Run all lighting (100W/90W headlight, tailight, signals, horn, speedo light) from the DC side with a 1.4A SLA battery.

The advantage to this that I can see is that I will be able to switch my headlight on/off. If my engine were to stall, my 1.4A SLA battery could sustain the 100W of lighitng for about 15 seconds or so before it were to die.

Thanks.

1.4A SLA is, I presume a 1.4 amp-hour sealed lead acid, yes?

If so, you're going to get a lot more than 15 seconds @ 100 watts.

100 watts, is about 8 amps, so you'd get 1.4/8 or about 10 minutes - you will probably get more like 5-8 minutes due to capacity loss at the relatively high discharge rate.

Have you considered an HID light? Lot more money, but only 50 watts and LOTS of light.

--Soren

[Beyond The Pale]

I have a baja designs kit and the rewound stator. It was on my bike when I got it. Without the rewound stator, the wiring diagram shows that yes the headlight along with everything else is on DC. The headlight is always on. With the dual winding stator, one coil has a HD AC regulator and runs the headlight. The headlight is always on. The other coil goes to the DC regulator and powers the tail/break light, turn signals, and horn.

I'm planning on addressing my blackness when the engine quits situation with some aux lighting that runs off of the battery. I'll leave the 90/100W headlight on AC. I mostly want the light for night trail riding, not the road. The head light kind of lacks in that situation. Most of the light goes straight ahead. Sometimes the light is just pointing into the air and is not lighting up the ground. I'm going to add some aux lighting that throws light all around, not a pencil beam like the headlight. Maybe a couple of 20W halogens. I'm also retrofitting my turn signals with LEDs. I got 100 high intensity yellows on ebay for like $5. I'm putting 40 in each front turn signal and 9 in each rear. I'll rig up a switch that turn them all on all the time. Decent light, and a total drain of just under 1 amp.

I don't know what's inside the Baja Designs DC rectifier/regulator. I see two choices an AC reg followed by a bridge like you are describing, or a bridge followed by a linear DC reg. Not an IC one but a big NPN transistor (darlington maybe) and a zener. If you try the AC reg plus bridge, be sure to check the charging voltage. If it stays over about 14.5 volts it will fry that battery in short order.

Batteries can take way more than what the mfgs rate them for. It might not be good for them and will surely reduce the lifetime, but it will work. Having to buy a new battery every year (or 2) is not a bad trade off for having light if the engine dies

[DSTerry]

Thanks for all the info. I will use the 16 awg wire for the stator, and upgrade the stock wiring. I guess the only questionable thing is my handlebar switch that controls the headlight, hi low beam, turn signals, etc. I'll have to wire into that. If it is at least 18awg then I think I should be fine.

The AC regulator and bridge rectifier should work fine. I have designed circuits similar to this but in much smaller scale and using capacitors to smooth out the ripple instead of a battery. But the theory is all the same.

So if I decide to use the auxillary bulb in the BD headlight (I forgot about that) on my DC side and run the headlight on the AC side, then would I have to completely by-pass my handlebar switch for turning the headlight on and off. And will I also loose my Hi/Low beam switch. I'll have to look at the wiring again because I think the switch uses a common ground for the hi/low beam and the horn. And my horn will be on DC, and headlight on AC which cannot share a ground.

How would one normally control an AC headlight on/off, hi/low using a standard handlebar switch that also controls the DC signals and horn?

Thanks.

[DSTerry]

1.4A SLA is, I presume a 1.4 amp-hour sealed lead acid, yes?

If so, you're going to get a lot more than 15 seconds @ 100 watts.

100 watts, is about 8 amps, so you'd get 1.4/8 or about 10 minutes - you will probably get more like 5-8 minutes due to capacity loss at the relatively high discharge rate.

Have you considered an HID light? Lot more money, but only 50 watts and LOTS of light.

--Soren

I was going off the data sheet for the battery, and it states a maximum discharge current of 6.4A for less than or equal to 5 minutes. Then it also states a maximum short duration discharge current of 14A for less than or equal to 10 seconds. I figured about 100W for the headlgiht, 10W for tailight, and a couple watts for the speedo light, and if I hit my brake, theirs another 20 watts or so. So with 130-140 Watts I'll be pulling around 11A.

It looks like the batteries are not very linear when discharging. Thats probably why they give you the different discharge specs. But either way, it will last for a little while if the engine dies and that's what I want.

But now I may just wire in a 20W auxillary bulb and use that as a backup light if necessary which would last significantly longer and should give me decent lighting.

[Triple B]

Hey Clenard & DSTerry

I agree with your concerns about how dark it gets when the bike stalls. I think something like this http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1395 would address those concerns. This has three other advantages one is if you do have a major electrical problem or the light bulb burns out you will still have the helmet light to get you home. Second is if you have that unfortunate BIG OFF you will have a light with you to find your Bike and hopefully your buddy will see your light and not run you over. The third is just for exploring how nice would it be to see down in the bottom of the canyon before you are committed to going there.

I know the HID helmet light is a bit pricey but if you do a lot of night rides I think it could save you a$$ and make the ride more enjoyable. Also explore that web site they also sell the dual light set up too.

Mr Snaggle you are the man. Your advice and writing skills are top notch.

[snaggleXR650]

Thanks for all the info. I will use the 16 awg wire for the stator, and upgrade the stock wiring. I guess the only questionable thing is my handlebar switch that controls the headlight, hi low beam, turn signals, etc. I'll have to wire into that. If it is at least 18awg then I think I should be fine.

The AC regulator and bridge rectifier should work fine. I have designed circuits similar to this but in much smaller scale and using capacitors to smooth out the ripple instead of a battery. But the theory is all the same.

So if I decide to use the auxillary bulb in the BD headlight (I forgot about that) on my DC side and run the headlight on the AC side, then would I have to completely by-pass my handlebar switch for turning the headlight on and off. And will I also loose my Hi/Low beam switch. I'll have to look at the wiring again because I think the switch uses a common ground for the hi/low beam and the horn. And my horn will be on DC, and headlight on AC which cannot share a ground.

How would one normally control an AC headlight on/off, hi/low using a standard handlebar switch that also controls the DC signals and horn?

Thanks.

Another good point. The DSK handlebar switch is not a heavy duty switch. Can it constantly handle 10A+? I didn't want to find out. My headlights are wired directly, bypassing the handlebar switch, always on when the bike is running. My little running light is wired to the DSK handlebar switch. Furthermore, my headlights are H7 single filament bulbs, so no Hi/Lo beam. In your case, you would have to have a ~15A 3 position switch wired just for the headlight.

Or, better yet, use the handlebar switch to supply 12VDC to a pair of ~15A 12VDC coil relays, if you want OFF/LO/HI or a DPDT (double pole double throw) relay if you just want LO/HI and always on. Letting the relays handle the high current switching is the way to go.

[DSTerry]

Or, better yet, use the handlebar switch to supply 12VDC to a pair of ~15A 12VDC coil relays, if you want OFF/LO/HI or a DPDT (double pole double throw) relay if you just want LO/HI and always on. Letting the relays handle the high current switching is the way to go.

I'll try and look up some specs for my DSK switch. Who knows maybe it can handle the higher current. But if not, I'll use some relays. That would be a pretty clean and simple setup with minimal parts. That would also solve the AC/DC grounding issue. I can use a DC source (DSK switch) to control the AC lines through the relay. They will then be isolated from each other.

Thanks.

[thouk]

I have the relay setup that Baja designs has. It works great for me. It is wired up so that the lights are always on. The lights are wired up to the a/c side so if the bike is not running the lights are off. I hope that helps, Tony

[DSTerry]

I called Baja Designs today to order a headlight assembly and ended up talking with one of the tech support guys for a while. He said that he has never heard of anyone using a single output stator to run both an AC headlight and a DC setup at the same time. He said the problem is that the AC headlight will take most of the current and not have enough for the DC system to charge the battery.

But if you have 150W output and the headlight is using 100W on the AC side, that should theoreticaly leave 50W to charge the DC side. I am sure their is some overhead invovled.

SnaggleXR650, I don't remember, but are you running a single output stator with your headlight in parallel with the regulator/rectifier (stator side)? You are running 110W of AC power, so does your DC side charge up just fine? What type of battery are you running.

The running light in the BD headlight is only a 3W, which seems a little weak for a backup light. My 1157 tailight bulb puts out more than that. I could always upgrade it with a higher wattage bulb depending on the style. I'll just wait and see when the headlight comes in.

I also brought up the DSK switch and the higher currents. They said running the H4 PIAA 80W/80W bulbs, they have not had a problem going through the switch. They are a bit more expensive, but if I can save the money on buying relays and wiring those in, it might be worth it. But if I went with a 100W they recommended I use the relays.

I just need to make up my mind and go for it.

[Beyond The Pale]

One issue is how the AC regulator works. They work by shorting out the stator. I've never taken one apart to see what's inside, but here is what I think is in there. They are not much more than a triac and some back to back zeners diodes set to trigger the triac when the instantaneous voltage gets to too high. Then the triac shorts out the stator until the next zero crossing. Not overly sophisticated.

[snaggleXR650]

I called Baja Designs today to order a headlight assembly and ended up talking with one of the tech support guys for a while. He said that he has never heard of anyone using a single output stator to run both an AC headlight and a DC setup at the same time. He said the problem is that the AC headlight will take most of the current and not have enough for the DC system to charge the battery.

But if you have 150W output and the headlight is using 100W on the AC side, that should theoreticaly leave 50W to charge the DC side. I am sure their is some overhead invovled.

SnaggleXR650, I don't remember, but are you running a single output stator with your headlight in parallel with the regulator/rectifier (stator side)? You are running 110W of AC power, so does your DC side charge up just fine? What type of battery are you running.

The running light in the BD headlight is only a 3W, which seems a little weak for a backup light. My 1157 tailight bulb puts out more than that. I could always upgrade it with a higher wattage bulb depending on the style. I'll just wait and see when the headlight comes in.

I also brought up the DSK switch and the higher currents. They said running the H4 PIAA 80W/80W bulbs, they have not had a problem going through the switch. They are a bit more expensive, but if I can save the money on buying relays and wiring those in, it might be worth it. But if I went with a 100W they recommended I use the relays.

I just need to make up my mind and go for it.

Yes, I use a single coil and run AC and DC all off the same stator coil. Here is how I have it wired, VERY SIMPLE. It's a .BMP file, make sure and zoom in IE to see it clearly.

http://members.cox.net/snaggletto/super%20stator%20schematic_revision2.BMP

The Black/Grey wires are the two wires coming off each end of the stator lighting coil and hook up directly to the 2 yellow wires on the standard Baja Designs combo reg/rec. The headlight is simply connected like a "Y". The AC voltage available on the Black/Grey wires is regulated only, not rectified. Rectified voltage only comes out on the BLACK/RED wires as shown in the drawing. Not shown is the standard issue Baja Designs battery, which would be hooked up immediately after the reg/rec on the BLACK/RED wires and then the whole DSK as normal runs off the battery, minus the headlights of course.

YES, the battery, and the whole DC side works just like it did before when I ran the stock stator and everything was DC. The headlight simply takes what it needs and the DSK gets what's left.

This particular setup is not for everyone, this is just how mine is, and it could be better. Running an 80W PIAA through the DSK handlebar switch would be much easier. It all depends on what YOU want. You *may* be able to get away with the 18awg wind, 10 poles, 32 turns/pole, 320 total turns and drive the 80W PIAA and charge a DSK battery. I think it would be ~borderline, but it may well work. I estimate the 18awg wind as ~125W, and the 16awg wind as 200W+. I don't recommend the 16awg wind (and the extra hassles that comes with it) unless you are pushing more than 100W of lighting....

[DSTerry]

Yes, that is exactly how I was planning on wiring it if I were to put the headlight on the AC side. Not sure why BD told me it most likely wouldn't work. Thats ok. It makes complete sense that it should work, and you have it working.

You say that their is extra hassle using the 16 awg wire. Could you explain so I know what to expect. I am going to use the 16 awg wire even if I go with the piaa bulbs. I like to overkill when it doesn't cost me much. And I don't consider hard labor as cost, I enjoy it to much.

[Beyond The Pale]

I believe it's simply that the 16 gage wire is larger and you have to wind it very carefully so the stator fits when you are done.

I don't know where you are in California, but there is this surplus store in the San Frenando valley, Apex, that used to have this cool square cross section magnet wire. Easier to pack it in well. I saw some there when I was getting the small 33 gage wire that I used to rewind my ignition coil last year.

[DSTerry]

Ok, that makes sense. I already purchased a 1 lb spool of 16 awg magnet wire. Snagglexr650 mentions the 32 turns on 10 poles for his 650. I have an '89 XR600. Are the stators similar enough to apply the exact same winding?

The DSK switch I have uses 18awg wire. 18 awg wire in open air (not bundled) can handle up to 16 amps. Even if it is bundled with a couple of other wires in my setup, the other wires will have very low current. So the only real heat source would be the single 100W headlight wire. So the big question, do I use the DSK switch 18awg wiring to switch my headlight on/off and control the hi/lo since the current will be around 8.5A. Or do I use 2 relays with 16 awg (22A capacity) for the headlight, and use the DSK switch to control the relays. Since I'll have a 200W stator, I'm leaning towards the thicker wire and relays but is it really necessary. I don't know.

[snaggleXR650]

Ok, that makes sense. I already purchased a 1 lb spool of 16 awg magnet wire. Snagglexr650 mentions the 32 turns on 10 poles for his 650. I have an '89 XR600. Are the stators similar enough to apply the exact same winding?

The DSK switch I have uses 18awg wire. 18 awg wire in open air (not bundled) can handle up to 16 amps. Even if it is bundled with a couple of other wires in my setup, the other wires will have very low current. So the only real heat source would be the single 100W headlight wire. So the big question, do I use the DSK switch 18awg wiring to switch my headlight on/off and control the hi/lo since the current will be around 8.5A. Or do I use 2 relays with 16 awg (22A capacity) for the headlight, and use the DSK switch to control the relays. Since I'll have a 200W stator, I'm leaning towards the thicker wire and relays but is it really necessary. I don't know.

Hey,

The hassle I referred to was not the actual winding, that's easy. It's having to deal with possibly, upgrading your stock wiring, bypassing handlebar switch etc... YOU DON'T want overkill in this situation, it's inefficient in terms of your regulator/rectifier. Wind for what you are running, or step up your load (extra lights).

I can't say for sure, but I've seen the "rewind your XR600 stator" webpage and it looks exactly like my XR650R's stator. I also believe the XR250 and 400 is the same also. I'm pretty sure they are all wound the same way.

Again, I didn't even attempt to run through the handlebar switch. Even though the wires may be 18awg, what about the switch internals? A common rating for switches is ~10A, anything rated higher is usually deemed "heavy duty." With an 80W headlight, you should be ok. You might even be ok with the 100W headlight, but I believe you will be pushing the limits by the time you add the other loads from the DSK. Heck, give it a shot, just fuse everything. Start out with smaller fuses and work up. When the fuses quit blowing and the switch doesn't melt then you are good to go ?

I wish I would have tried some other scenarios. There are a bunch of different ways to setup a system like this. You are inspiring me to go back in and redo mine. Start off simple (going through the handlebar switch, stock wiring etc...) if you have a problem, then address the problem at that time. You might smoke a switch, but at least you'll have tried. I was a wuss and addressed potential problems before they were even problems.

One thing I'm curious about though is the potential of the 18awg winding. I've got a feeling that the 18awg wind and an 80W headlight + DSK (especially with LED tail/turns) would work.

Just be careful if you go with the 16awg winding and an 80W headlight. Use fuses, and BE CAREFUL. I don't want to hear that you burnt your bike and house down because of my advice ? .

[Beyond The Pale]

There were a few changes to the stator over the years. The early years only used one winding for the ignition coil. Later years ,including my 93, used two. I also think that the earlier years have a stator form that is only half of the circle. That means there are only 4 windings available not 10. This is what is shown on the http://www.crustyquinns.com/tech/stator.html page. I think the bike was an 87 in that case. I'm pretty sure you 89 is the same. I don't know when the change was made.

[DSTerry]

Don't worry, I keep a fire extinguisher hanging on the wall in the garage!

The only problem with keeping it simple (when you are border line) is that I don't want to start blowing fuses. I don't get out to the desert that often, and the last thing I want is to be tracing down problems in the middle of a ride.

I would rather make it bulletproof if possible and never have to look at it again. That's why all the questions.

I decided to run the 90W/100W halogen bulb on AC and use the 16awg wire to some relays and have my DSK switch control the relays. It is a simple setup and seems like it will be very adequate. It makes more sense to me than trying to use wimpy wire with a lower wattage piaa bulb to just get by. Plus I don't have LED lights anywhere, so I will constantly be using at least another 20W on my taillight, 10W on a front running light, and a couple of watts on my speedometer light. And whenever I hit the brakes, theres another 30W+. So I think rewinding for a 200W stator should be just about right.

I just went to service honda microfiche for my 89, and yup, the 85-90 XR600 stators only have 5 poles. 1 for the ignition and 4 for the lighting. And it looks like all 4 poles are used.

Hmm. Back to the drawing board. Now what options do I have. At least I learned a lot. Do they even make a high power stator for the older bikes? I wonder how much power I could get out of rewinding just my 4 poles with thicker wire. But then I won't get as many turns. That probalby won't work.

[Beyond The Pale]

I'm about 99% certain that the later stators will fit in the earlier bikes. If you keep an eye on ebay, you should be able to pick one up for not too much. Just use a standard 55w headlight bulb until you can get a better stator.

On that rewinding webpage link that I put in my previous post, the guy rewound his lighting coil and it ended up blowing his regulator. He used .8mm wire, which is about 20 gage, and wound 75 turns per pole. Perhaps there is more power available even with only 4 poles. My Baja Designs stator uses 5 poles on each winding and is rated at 125 watts. Perhaps 100 watts is possible from 4 poles.

I'm putting my turn signals and tail light/brake light on a DIY LED diet. I want to save battery amps for more headlight.