ignition coil

[x.X.Cpt.Rollhart.X.x]

Hi, I am working on a hybrid and I have a lot of problems with my ignition. I got a electric BBQ ignitor with a 9 volt batterie (http://media.putfile.com/Sparlhybrid) But some person said me that It wont be enough to ignite my chamber because it is pressurized. DR told me to use a car ignition coil. And Dont know what kind of ignition coil I need and which one ...

I did this little drawing. Tell me If it will work properly. I would put 2 switches. One safety switch and one momentany button switch at the end of 50 feet of wire.

thank you

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[carlbelcher]

You need to wire your batteries in series not in parallel other than that you should be fine. Also you can use pretty much any ignition coil you can find.

EDIT:

Series:


Parallel:

[x.X.Cpt.Rollhart.X.x]

yes, I know that I need to put my batteries in series.

Someperson on spudtech said me to use a capacitor, where Do i need to put it ?

[carlbelcher]

Before you add a capacitor to the circuit I would add a condenser. It well give you a much better spark from the coil. Sometimes without a condenser you might not get a spark at all from the coil.

Here is a diagram of a motorcycle ignition system to show here to put the condenser. For your circuit you would just replace the "points" that would normally control the spark with your button.

[x.X.Cpt.Rollhart.X.x]

Why is there an "earth" at bottom the of the coil ?

[carlbelcher]

It's not an "earth" it's a ground.

[FiveseveN]

Earth, ground, mass, duuh same thing. But that diagram looks wierd to say the least.
1st of all: condenser = capacitor. It's been discussed before.
Second: The ignition coil is an autotransformer, right?! That doesn't mean it's a transformer used in automobiles It means the primary and secondary are connected. They have common ground. So in your diagram, the primary is always under tension. So what's the use for the cap and switch? The cap would never get a chance to charge because it would bleed through the coil.
Maybe my brain is a mess or maybe you're using a special 4-pole coil.

[frogy]

I think carl pulled that out of his ass, or maybe someone elses lol

And you dont really want a On\Off switch there, if anything you want a momentary switch, for the ignition coil to work it just needs a brief current, you could really just use a 9v battery and tap a wire to the terminals really fast and it'd work...

Most ignition coils are only rated for 14v, so I don't understand how people run 10,000 V thats in a camera flash capacitor through them, and a camera flash capacitor is 300v, but it runs through a step-up transformer so it comes out as 10 kv

[carlbelcher]

The idea with that diagram (that I found on google) was to show how an ignition system works in this case a motorcycle ignition. It does show a switch it's just in the from of points on a motorcycle. And yes a condenser is the same thing as a capacitor it just a lager capacitor use in automotive applications. I thought that buying a condenser from an auto part store would be a lot easier then try to find the right capacitor. and frogy most ignition coils are only 1:100. The coil will work a lot better with a condenser/capacitor without one it may not work at all.

[frogy]

If anything use a Momentary switch, and a ignition coil is wound 1:100so that means 9v goes to 900v+...

I don't understand how 300v from a flash capacitor cant arch buy 12v from a car battery can, I though voltage was relevant to aching...

Enlighten me here, I'm going to spend $15 on an ignition coil probably, will 300v from a flash capacitor break it if it's only rated to 14v or not since it's only very break periods of 300v...

[FiveseveN]

I don't understand how 300v from a flash capacitor cant arch buy 12v from a car battery can, I though voltage was relevant to aching...

Arching in a stun gun / BBQ igniter etc. is produced by voltage that's higher than air's dielectric breakdown point (about 10.000v per centimeter). So air becomes conductive and the electrons jump the gap, just like in lightning, but obviously at a smaller scale. The greater the voltage, the bigger the gap can be.

Sparking from a 12v car batery works like this:
No electrode is perfectly flat. There will be microscopic irregularities on its surface. When two electrodes come together, these irregularities act like tiny resistors. Ohmic heating is violent enough to cause these little particles to explode. This is the spark one witnesses. The more amps a battery can output, the greater the heat
The size of the spark depends on current and material of the electrodes.

[SpudStuff]

i know where to get the coils but how much am i looking at for a new coil

[frogy]

$15 at "AutoZone"

$20 MAX
Can probably get for $10

Junkyard = FTW