Ignition Coils - cheap, quick qnd easy

[Niceonetidy]

Well chaps, I have looked for a cheap reliable, small compact ignition system for petrol ic engines. And so far, this is the bet I have found. . . . . . .

http://www.hobbyking.com/hobbyking/store/__10996__Replacement_CDI_Ignition_for_RCG_50CC_Engines.html

$20 for a complete system including the hall sensor. And they have twin cylinder versus too for another ten dollars. This unit will output three sparks In Quick succession. I have one here and its going on a friends cnc made engine. I will let you know how it goes. This unit make a big spark !

Cheers

Colin

 

[IC-man]

Hi all,
About a week ago I found a transistor ign. System using hall trigger that was stated as fail safe in the event of engine stopping with ign left on. I can't find it now. Any ideas where I can find it people.
Thanks All.

 

[TonyM]

Was it this one. https://www.homemodelenginemachinist.com/threads/a-new-ignition-circuit.20415/ I've built a few of these and they work fine.

 

[propclock]

Beware the COP primary resistance is VERY low.
I have cloned the Dave Sage ignition IGBT system for myself and members of
Bay Area Engine Modelers. BAEM. I use the same 5$ coils and they work great.
But I recommend a 4x AA nimh battery supply. They can only supply so much current.
With a BIG 12v battery, you can draw a lot of current. Add a ballast resistor or
reduce the voltage some way. They can be made quite small if you trim all the excess
plastic/ connectors off. Just my 1.414 cents worth.

 

[IC-man]

Was it this one. https://www.homemodelenginemachinist.com/threads/a-new-ignition-circuit.20415/ I've built a few of these and they work fine.

Hi Tony it looks might it might be the one but can't find the circuit diagram. I have been playing around with many different circuits over the years with various results. I find one of the main problems is the earth has to be really good. Otherwise it blows the P transistor, the hall, or both.
Perhaps I'm being stupid but more help to find the diagram would be useful ( I did notice it has had an update but could find any circuits)
Thanks anyway.
Graham

 

[IC-man]

Hi Tony,
Thanks for you help I've found it now.
Graham

 

[dsage]

See post number 63. It's the final circuit. But you might read further down the posts for other tips.
https://www.homemodelenginemachinist.com/threads/a-new-ignition-circuit.20415/page-4

As mentioned above (by propclock) the COP coils need to have current limiting. Either the NIMH battery trick or something like a 5 ohm ballast resistor depending on how much spark you need (less resistance - more spark).