Solid HT white wire data

etacovda

Member
Local time
4:33 AM
Joined
Feb 7, 2009
Messages
66
My adventures with the white wire


So, in this recent thread duivendyk helped me with his electrical know-how on how to get some solid data from the white wire.

The low down -

After some measurements, we found that the white wire on my HT puts out roughly 6v positive, and 18v negative. Obviously, theres more output on the negative part so using a charging circuit using the positive side is a bit of a waste. Duivendyk suggested using a diode connected to the battery and white wire, with a capacitor, in both directions to find out this peak voltage. (figure 1). This is how we arrived at the 6v+, 18.8v negative voltages.

After finding this out, using a negative charge circuit with a peak to peak rectifier (and a shunt connection to my multimeter to read lower) we came up with the following figures for current and therefore wattage. I butchered one of my nicads (came from a power drill) to make a 6v battery to get our 6v numbers.

Below are the numbers.

wire wire to ground resistance = 2.8Ohm

12v circuit
Idle
0.175A * 13.9v = 2.4w
Peak
0.328A * 13.9V = 4.55w

6v circuit
Idle
0.348A * 6.6V = 2.3w
Peak
0.725A * 6.6 = 4.8w

I'll note that all of these were numbers tested tonight in one run, with the engine going the whole time, so they should be consistent.

Using this circuit, we can see that it is possible to get useful wattage out of the white wire. My next mission is to make a charging circuit with overvoltage protection for an SLA battery. I myself may not end up using it, as ill probably use my power tool nicads since they're lighter, and will go to waste.

I will add the circuit diagrams later on, i have to go out to my fiancees work do now. Hopefully this'll be useful and consolidate into a decent thread on the white wire, and making a charging circuit, since theres not any real solid information on making a circuit at present. I am also hoping that if anyone else follows my testing here (circuits are easy and very cheap to build) we will get a nice range of white wire tests to see how consistant the white wire output is across numerous engines.
 
Last edited:
Good work. Before you get into overvoltage protection, you might try to connect directly to a battery and see if the output causes the battery to heat up (if NiMH) or bubble (if lead acid).

The 1/3 amp peak output may well be a level that the battery can self regulate. It depends on the size of the battery.

If I ever get back to working on my light setup, I will use a single diode on the negative side (diode connected to battery ground and pointing to WW) with a 10 battery pack of AA NiMH, which runs close to 13V. If they get too hot, a 14V zener could be added to drain off any excess voltage.
 
If you keep on charging any battery without discharging it,you'll end up overcharging the thing,it's just a matter of time!.How quickly you charge it determines how long it takes until you reach that point.The single diode negative rectifier works fine but the more complicated peak to peak cicuit puts out quite a bit more power.(takes a cap and extra diode).Use higher power rated diodes or a couple in parallel.This is a low duty factor circuit of necessity (the ignition pulses are short but of high amplitude) and the currents are in the amperes.Our research established that a 6V battery setup provided a bit more energy storage than a 12V.Using a Schotky(low voltage drop) diode could make sense in the 6V case.
 
Last edited by a moderator:
I have a LED torch with DC 4.5v in and DC 4.5v out. It's one of those wind up ones with an internal battery.

I plan to go

WW > Diode > resister > Battery > torch > Ground.

and from the DC out in the torch i will power the rear lights.

I have a 30min trip each way to work, with a 1.5amp hour battery i hope would do the job.

my problem is working out what resisters and diodes to use and in what sequence. I'll post up a pic of my plan

EDIT: here's that pic
 

Attachments

  • electonicsplan.jpg
    electonicsplan.jpg
    40.3 KB · Views: 754
Last edited:
As I understand it,you want to use your torch as the headlight and power you taillight from its 4.5 V internal battery.Then you intend to use a 6 V battery, to be charged from the WW to power the torch with in turn.Rather a convoluted scheme.I presume you need more storage than the torch battery can provide.
Some questions: Can the torch battery be electrically isolated from the metal frame ?.Do you know what sort of battery is in it?.Do you have a multi meter,preferably with an analog readout.Please let me know,there may be better ways to achieve your objective.
 
As I understand it,you want to use your torch as the headlight and power you taillight from its 4.5 V internal battery.Then you intend to use a 6 V battery, to be charged from the WW to power the torch with in turn.Rather a convoluted scheme.I presume you need more storage than the torch battery can provide.
Some questions: Can the torch battery be electrically isolated from the metal frame ?.Do you know what sort of battery is in it?.Do you have a multi meter,preferably with an analog readout.Please let me know,there may be better ways to achieve your objective.

I have no idea what is inside of it.

It's a wind/crank headlamp/torch where i wind it up and electrical charge is stored in it's internal battery. it has 4.5v input and output :)

the problem is that when it's mounted onto the bike it's impossible to wind the crank without getting out the screwdriver and taking it off it's mount.

hmm, ill go outside now and get it, take the cover off and take a look inside

it's this

http://www.sontax.com.au/promo/Magictorch.htm

ok, it has NiMH 2/3AA 600mAh 3.6v written on the battery. ( which is inside the torch, i believe it's isolated and just powers the torch just like any other battery would)

i don't have a multimeter though :/
 
Last edited:
Something does not add up voltage wise, 3AAA NMH cells means a 3.6V battery not 4.5 V (1.2V per cell) so what this story about a 4.5V battery I don't understand either what's that 2 prefix means if anything.
600 mHA isn't much capacity.Why are you stuck on this torch,because you have it already?.Not having a meter is a handicap.
 
ues i have it already, it works reallly well, has a solid mounting and it really bright.


yes i believe its strange that the DC input doesn't match the internal battery specification.

Although that could be attributed that it must presume that you're running both the rear light aswell as the front. The DC output on the torch apparenty can also be used as a mobile phone charger, but i only want it to power the rear light :)



the rear light = 3x red LED incased in a red/black mountable rectangular box. i have no more info than that on it other than that it came with the torch and it also is extremely bright.


but based upon my diagram above do you think my 'plan' would work ?
 
Back
Top