White wire succses story!!!!

[duivendyk]

Good news,someone in possesion of a meter & possibly some electrical smarts (not all that much are needed believe me) & hopefully still in a quest for knowledge & enlightenment.
I suppose the voltages you measured were ac. voltages,this actually means little in terms of actual instantaneous values,this ac output actually consists of short fairly high amplitude (maybe 15V or so, or higher) ac. pulses,that is a positive excursion to a peak followed by a negative going return through zero to a negative peak (not necessarily of the same amplitude) and then back to zero again,followed by a long period of zero until the next ignition cycle.An incandescent lightbulb responds to the average power in this waveform (I spare you the math it involves integrals).A typical cheapy meter rectifies this ac and averages it to a dc. value and then displays the power equivalent of a nice wellbehaved sine wave voitage that would have the same average value.This scheme does not work well for the sort of weird waveforms the white wire puts out,so these measurement don't give you much insight as to wether it's feasible to charge a battery from the white wire.If you have no interest in looking into this further tell me, then I won't bug you anymore.I don't have an HT setup and am not all that likely to acquire one either,however devising a battery charge circuit using the white wire output would be an interesting challenge and keep me from getting bored, but to this end I need an willing accomplice.You might learn something worthwhile too.

 

[cooltoy]

I'll be lurking in the sidelines.
Carry on!

 

[etacovda]

well ive got a couple of meters (digital though, not sure it matters) - id be happy to offer a 2nd motor test to verify results. 49cc happytime here. Quite keen on setting up an SLA charging system for it, so I'm all for some help!

 

[BSA]

Good news,someone in possesion of a meter & possibly some electrical smarts (not all that much are needed believe me) & hopefully still in a quest for knowledge & enlightenment.
I suppose the voltages you measured were ac. voltages,this actually means little in terms of actual instantaneous values,this ac output actually consists of short fairly high amplitude (maybe 15V or so, or higher) ac. pulses,that is a positive excursion to a peak followed by a negative going return through zero to a negative peak (not necessarily of the same amplitude) and then back to zero again,followed by a long period of zero until the next ignition cycle.An incandescent lightbulb responds to the average power in this waveform (I spare you the math it involves integrals).A typical cheapy meter rectifies this ac and averages it to a dc. value and then displays the power equivalent of a nice wellbehaved sine wave voitage that would have the same average value.This scheme does not work well for the sort of weird waveforms the white wire puts out,so these measurement don't give you much insight as to wether it's feasible to charge a battery from the white wire.If you have no interest in looking into this further tell me, then I won't bug you anymore.I don't have an HT setup and am not all that likely to acquire one either,however devising a battery charge circuit using the white wire output would be an interesting challenge and keep me from getting bored, but to this end I need an willing accomplice.You might learn something worthwhile too.

I was gonna try 2 charge a battery but I ran out of funds to build a circuit. Some other person on here has done though.

BSA

 

[etacovda]

alright, so i have a psu here that im fairly ok butching which has a multitude of caps and diodes to build a rectifying circuit - id assume you'd smooth the dc side rather than the AC, yes?

 

[etacovda]

ok, so ive just stolen a bridge rec out of the psu - a gbu401, and connected it to a pair of connector blocks - im going to test the voltage i get out of it now...

 

[duivendyk]

I had some misgivings BSA that you'd be in a penurious state.You get ripped off in the UK for electronic components,I think,I once had to get some adapter plug a few years ago,the thing cost a small fortune &had a fuse in it too, crazy!.May be somebody else will crawl out of the woodwork,come on, lurkin= shirkin.
As far as charging a battery is concerned,if you rectify what's coming out of the white wire,you'd see two adjacent dc pulses (corresponding to the pos.&neg cycle of the ww output) then a whole lot of nothing then another set of pulses (the next ignition cycle).These pulses could be quite substantial,couldwell be over 13 V.,if that is the case you'r in luck and you could in principle charge a 12V battery,if not you could still go for a 6V charging circuit
The output of the bridge rectifier (4 diode) should be FLOATING,nothing connected to the frame or the engine,if you do you are going to blow up some diodes.
It would be useful to find out first what the all important PEAK voltages are on the white wire,this requires a peak detector,which can be put together with a diode a capacitor and a resistor,plus of cource a dc voltmeter,not hard.The cap &resistor value should be chosen such that the product of the resistor value (in kilo ohms) and the Cap. value (in microfarads) should be roughly between 2000 and 10,000.For instance a 220k resistor and a 10 microfarad (electrolytic) cap have a product of 220x10=2200 which is within range,a 10 k resistor with a 470 microfarad cap would be 4700, OK too
The diode connects to the white wire, the cap in parallel with the resistor are connected from the other side of the diode and to the body of the engine or the frame (ground),the meter is connected across the cap/resistor combination.It is important to check both polarities,either by building two circuits or else by making different connections.To measure the positive output, the band on the diode should point to the plus side of the elctrolytic cap and one side of the resistor,the negative side of goes to ground as does the other side of the resistor.For the negative pulse the opposite applies,band on the diode towards the white wire,other diode end connected to resistor/cap parallel combination,pos. side of cap goes to ground.If you have enough parts (two of each) you can hook up both circuits which will make taking measurements quicker.These outputs should be measured at idle and at normal running speed.With this info it will be much easier to assess what the possibilities are and to devise a possibly viable charging circuit.
It's also useful to check the resistance to ground of the white wire with the engine not running,check both polarities by reversing the leads,they could be different.Is somebody out there game to do this,it's pretty straightforward and the instructions are pretty clear I think and it would provide much needed info.

 

[etacovda]

ok, so i appear to be getting around 10-18v out of my white wire. I have a 400v 470uF cap from the psu that i will put across the dc side to filter it a bit and see what i get...

 

[etacovda]

duivendyk - can i use any resistor for this load, or will it have to be able to handle wattage - id assume any is ok as its going straight to ground?
dont want exploding resistors on my hands if i can help it!

oh, and also - i hooked up a 12v 5w light straight to the white wire, which worked - engine didnt falter at all - light was quite dim though. Testing one side only of the light showed the pause peak pause pause that you described - but my multimeter seems to go quite sporadic on its readings (jumps around hugely) with both connected anywhere in the circuit, it never stops for a reading if its fully connnected.

white wire, 2.8ohm load with engine off in both directions from white to engine ground.

ok, have a 47uF cap in parallel with a 149kOhm resistor (which calcs to 7000 on your little formula) - diode pointed towards one leg of the parallel pair, from white wire, with parallel pairs other leg pointed to engine ground. Havent plugged it in yet...

 

[etacovda]

ok, so i did a bit of wandering around reading about circuits, decided what i had was safe. Now, i used a 50v 47uF cap, 150kO resistor and a diode as above.

In positive (white wire to diode, diode to cap pos with resistor in parallel, both cap + res to ground) = peak of 6.8v

In negative (white wire to diode, diode facing white wire, reversed the direction of cap as you said, etc) - peak voltage -18.8v

looks like we have a charging circuit definitely possible with this, yes? My bike idles at, id guess, 1500 rpm - no noticable difference in peak voltage, perhaps 1v less max on the positive (ie seeing around 5.5-5.8v) and .5ish less on the negative.