Can a coil be used to chardge a battery?

[supportthebillofrights]

The coil of a two cycle engine is located parallel to the circumference of the fly wheel, which has a magnet at one point along its circumference, that when spinning relative to the coil, produces a 12kv to 25kv charge in the coil, the release of which to the spark plug is timed by mechanical points or a electronic ignition.

In any event, I am wondering, that if it were possible to add another separate coil relative to the flywheel, if it could be used to charge a 6 volt 18 amp(?) lead acid battery, by reducing the voltage to 6 volts ac and running it through a 6 volt, volt voltage regulator/rectifier to the battery ?

If anyone has any ideas on this I would like to here them, even if it to tell me it is stupid. I have a good understanding of Mechanics, but my electrical knowledge is poor. I am looking for a passive way to charge the battery on my motor bicycle.

Thanks,

 

[Russlk]

Most motorcycles use that method to charge the battery. The voltage at the points is low, it could be used to charge the battery, but is probably not designed to produce enuf current to light a lamp. I had a small motorcycle, the battery went dead, so I ran it without. The dynamo would light the lamps, but not blow the horn.

If you can get another magneto, remove the coil and re-wind it with heavier wire, mount it over the magnets, it will work. You need to consider saturation of the magnetic core, otherwise the battery will be overcharged or overheated at high speed. A rectifier and zener diode can control the voltage, but there has to be a mechanism to limit the current or the zener will burn up. Saturation of the core at high current can provide the current limit.

 

[supportthebillofrights]

Thanks for the reply, but you went over my head.

I understand the benifits of rewinding the coil, but in the case of a 2 cycle engines, the coil windings are embedded in epoxy resin and there is not much that can be done with them beyond replacing the single sparkplug wire attached to them.

You make mention of the fact that the voltage at the points is low and could be used to charge a battery. If this is the case, would it be possibe to simply run a wire, from the wire that goes to the points or electronic ignition, to a 6v voltage regulator / rectifier and charge my battery, while running the lights off the battery? I think the first law of thermodynamics, will nex this out though.

The lights will be using about a max of 100 watts/ 20 amps, with the head light on high, if I understand the calculations. So I think I need a minimum of a 20 amp source to charge the battery.

The lights are a State vehicle law issue.

 

[john1]

Yes.

Additional coils can be purchased,
made to fit in the flywheel,
they are called 'Lighting Coils'

Running extra stuff from the low tension side
of the ignition coils is not recommended.

The output is rough, and lights will flicker
at lower engine revs. (normally no battery)

You might have to get special parts for
controlling the charging, but it can be done.

Regards, John

 

[john1]

see:

"lighting coil", images, google

Regards, John

 

[stevez]

Worth noting is that what comes out must have gone in-and then some. At 100% efficiency it will take 1 hp to generate 746 watts. That extra load on a large engine is negligible but on a small engine it might be noticed.

 

[ante]

Note that 746W is 124Amps in a 6Volt battery, if it does not explode it will be fully charged in minutes! (at 100% efficiency) ! Normal charge is about 2-3 Amps for a 6V 18Ah battery that’s only 10 – 20 W and this will hardly be noticeable in performance.

Ante :roll: