Converting to DC Lighting

[tripod.psend]

Hi, I have a Honda PC50 which has AC lighting, no battery, no indicators and no brake light. I'm planning on converting the whole lighting system to DC voltage with a battery with indicators and brake light. I just have a few technical questions about this.

I have attached the wiring diagram for my Honda PC50.

- Can someone please tell me if this flywheel AC generator (stator/magneto) is a 'three phase three wire' or a 'single phase 3 wire' ???

I need to know which rectifier to buy.

- Also would it be OK to connect the three wires together??? creating what looks like a parallel connection of all coils to create more amps for better battery charging and light performance. I am worried that this might fry the coils by somehow short circuiting them to each other.

Replies appreciated. Wiring diagram attached.
Chris.

[stinkwheel]

In answer to your query, it is a single wire AC generator. When the lighting is on it splits the output between the horn and the lights. When it's off, the horn getts the full whack of the 2.5A AC it is capable of producing.

If you wanted to rectify it you would need to use a two wire selenium rectifier.

This is a total waste of time, effort and money because this bike produces nothing like the output needed to power even one off your list of battery, brakelight and flashers. Rectifying removes half the power straight away and there are other losses inline leaving you with (ballpark) 1A DC output.

Not much you can do with a 1A DC charging system. You still have to power the headlamp and horn from that. It would be straining the boundries of what could be done even using the most modern and cutting edge LEDs.

The headlight on this bike is NOT to see in the dark with, it's to be seen in the dark by.. If you're lucky. I would not advise using it in the dark anywhere there aren't streetlights.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[tripod.psend]

I don't understand why it splits the wiring in the generator coil. Why didn't they just split the wiring outside in the light switch. The horn would still get the full whack of the 2.5A AC it is capable of producing, like you said.

Are you sure this is not a split of 3 x 2.5A AC coils which I could join to create 7.5A AC then rectify to DC?

The later models included a rectifier, battery and indicators off the same magneto/generator from only one wire. It must be possible to charge a battery. I've attached the later models wiring diagram.

Chris.

[stinkwheel]

Looks like they are using the headlamp output to charge the battery when the headlight is off and the horn output to power the brake light.

The latter should work ok as long as you don't want to sound the horn and brake at the same time. The former I suspect doesn't work very well. Having had one of these bikes myself, I wouldn't like to try using the indicators while the headlight is on.

By all means try but it really isn't going to output enough to run DC lighting. You'll notice they've fitted a 2Ah battery which matches the draw for the lighting circuit. With the lights on, it won't be charging (at all).

You may also notice they've dropped the taillight to a 2W bulb on that model! For reference, that's the same power bulb as I have in the instrument panel on my VFR.

Have a crack. Just don't be disappointed when the headlight goes on and off with the flashers.

EDIT: To clarify, it's one coil. Look at the earth (singular).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[tripod.psend]

Yes I'm confused as to where to start as I do not understand this generator. So it has one coil. Can anyone understand how it is split? What would happen if I just joined the three output wires together with no electrics turned on?

The diagram shows earth, then the first bottom wire on the coil at 2 turns, the next wire 3 turns further up then the last 3 turns even further up.
Does this mean that the bottom wire is producing less than the other 2 wires? This may cause problems connecting the 3 wires together.

I really can't understand why there is not just 1 wire that splits into 3.

Chris.

[unitynotsocri...]

.in theory you could convert it to a dc lighting arrangment but you'd get no benefit as bulbs are very happy with ac and having the coils all on,or wired in, all the time would affect the engines power output slightly,as the coils would be 'on' all the time .

you'd do far better replacing the indicator /side/brake light bulbs with LED ones and finding a better replacement headlamp bulb.many cycles are fitted with much better lighting thesedays.

The three coils all share the same earth ,and each coil produces a different amount of juice,its NOT three phase,ITS A SINGLE COIL with 'taps' to take off less than the full power.
____________________
nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[tripod.psend]

So if I'm understanding correctly it is the top tap(wire) that is working at the coils full power? Then the middle wire takes a little less and the bottom one even lesser.

So in theory to get the full power from the coil I could just use the top tap(wire) and forget about the other two? There would be no need to literally solder the three wires together to achieve full power?

[unitynotsocri...]

yep i think thats right.the first 2 coils are lower output settings,more coils =more power.if you did go through the trouble of converting to dc then the third tap would be your 'charging coil.' remember though that many small bikes using batteries still have their lighting power coming from seprate lighting coils in the generator.
because the output on your scoot is so small ,i can't see any advantages in changing any of it except for LED indicators and brake/side/lights.These would just reduce the power needed and LED indicator bulbs may help your indicators to flash normally at traffic lights without having to rev it a bit.If its a saftey/visibilty issue then I'd just wear a flourescant pink jacket or buy some mountain bike lights for extra saftey.
____________________
nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[tripod.psend]

Yes just for safety, I would like the lights on full even when at low revs waiting at junctions. So a battery would be my first idea.

So this coil in the diagram is one coil with tap wires coming out at different intervals. NOT one long coil with another half coil wound over it then another shorter quarter coil wound over both???

I can't understand why, if it is just one long coil, they didn't just have one wire, then split that wire into three. Surely the diagram is showing three different length coils wound over the top of each other, all connected to the same earth.

I just need to understand this correctly because I am going to try this dc conversion with a battery anyway. I just need to understand if it would be best to get most power to join the outputs or just use the top wire at the coils longest length.

[finpos]

I'm a bit confused about the earthing arrangement which I may need to have a think about but what you would normally do is to take a three wires coming from the coil and feed those into a modern 3-phase regulator/rectifier from a scooter, then connect the output of that to the battery. Then run everything off the battery.

May work, may not.

f.

[unitynotsocri...]

the coil is basically one long wire with wires coming off it called taps.The taps allow the selection of different power outputs depending on wether the head/sidelights are on or off.

You may be better using a mountain bike LED headlight for saftey and as a dayriding lamp,or the pink flourescant jacket.for all the messing about involved you could restore another 50cc goped.
____________________
nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[Teflon-Mike]

With that small a generator; why not just 'give up'; use a battery; but forget trying to charge it off the engine, just go 'total loss'.
How long do you ride for, in one go?
Works on push bikes, and this isn't much different.
Just have two batteries; one on a charger on a window sill; one on the bike, and swap them each time you go out.

Use bikes genny for headlamp & horn, as standard; then go 12v for tail & stop and indies if you want them; again on LED bulbs, with solid state flasher, for low consumption & long battery life. Use LED 'side' light on 12 TL circuit, to augment headlamp at low revs.....
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[tripod.psend]

I'm going to try it anyway, I may use a regulator and 3v or 4v battery and bulbs. This may sort the charging if very poor generator.

One more thing I need to know is if -ve of the coil is 0V or -V.
Is it putting out +3V and -3V OR +6V and 0V.

From looking at the diagram with battery it looks as if the coil and dc battery share the same ground, so this suggests the ground is 0V? Am I correct?

[unitynotsocri...]

because the coil outputs AC,or alternating current,the voltage swings between - 3v and + 3v. O v is a reference to a dc voltage.

When you put a diode(a rectifier) in the circuit the voltage becomes DC so a -3v +3v coil would output + 3v DC

still reccomend the flourescant pink jacket or mountain bike lamps though,or wire it as standard and if you sell it in twenty years time it will get a better price!
____________________
nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[stinkwheel]

The coil itself consists of a single, crescent shaped steel block with a length of copper wire wrapped round it. There are three branches coming off this wire at different points along its length.

The rotor magnets spin round it and generate an alternating current in the coil. The amount of current depends on the length of wire.

It's one coil, one phase. To get a different phase, you'd need another coil mounted in a different position. A three phase system has three seperate coils mounted 120 degrees apart with a common earth.

[tripod.psend]

OK well I now understand that the coil is basically split into 3 outputs in series, so I would disconnect the lower 2 and just use the top C1 output for what I'm going to do.

I'll probably be best testing the circuit with a voltmeter before I can fully understand the outputs of the coil, I'm getting the bike on the road tomorrow and will buy a voltmeter.

stinkwheel, you say it's 6v AC. That means it's alternating between +8.5v and -8.5v.

I cant mentally understand this because surely that would mean it is making +17V full in each direction which would blow the 6V bulbs it has.

I can understand -3V and +3V giving out 6V in each direction. Or maybe the ground on the coil is at 0V.

Well I'll test the outputs tomorrow and go from there.
Thanks.

[stinkwheel]

[stinkwheel]

I thought of a better analogy.

Driving a car.

The road is the wire, the car is the current, the engine is the generator and the velocity of the car is the voltage. The power is the size of the car multiplied by its velocity

DC would be driving the car forwards at a steady speed round in a circle.

AC would be driving the car forwards round the circle, coasting to a halt then driving it in reverse, stopping, driving forwards etc.

If I drive the car up to 10mph and stop then reverse up to 10mph and stop. My maximum velocity was + or - 10mph. My velocity was zero, I'm back where I started. My rms speed (assuming constant acceleration and deceleration) was 7.07 mph. There is no way I could ever be doing 20mph.

So driving up to 10mph then reversing at 10mph would be the equivalent of driving in a straight line at 7.07mph.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[unitynotsocri...]

thanks stinkwheel,
apoligies tripo.psend for my appalling maths.. +6v it is.If you need your house rewiring call me in a year!
____________________
nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[tripod.psend]

thanks stink wheel, I did do AS electronics but cant remember a lot.

I am now confused about how to measure the max current output of the generator.

stinkwheel:

[neil.]

Hook up the ammeter in series with the circuit, power everything up (lights, horn, the lot) and it'll tell you how much current is being drawn.

[stinkwheel]

I worked it out by combining the wattage of the head and tail lights. I'm aware it is only just capable of lighting those up when you rev the bottom off it so I took that as maximum output.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[tripod.psend]

Yes this would give the current being drawn with the max load currently on the bike.

I'm wanting to add a battery, indicators etc.

I need to know the maximum possible current the generator can give out. So I can calculate the max watts it can handle.

I was thinking maybe wire it up to a 240v 100w light bulb and see if that shows the max current the alternator can possibly give out.

[stinkwheel]

[tripod.psend]

So does anyone know a correct way to measure the maximum current output from the coil/flywheel??

I'm scared of blowing the coil if I just connect from output wire to frame.

Would a large watt 6V bulb show the maximum current. As it would not draw anymore current as the wattage is too high for the bikes coil/flywheel. Would this be the max current output of the coil/flywheel.

Well if it doesn't fully light them then at low revs it would show the max current output. But I want to test it to the max.