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Robert
Falcone Joined: 07 Apr 2020 Location: Scotland Status: Offline Points: 60 |
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Posted: 05 Jun 2020 at 18:02 |
The coils on my 82 sp get extremely hot if I have the ignition on for even 5 minutes.
I’m running a Dyna ignition with standard coils I do know they recommend 5 ohm coils with this system as they say the standard coil will run hot - but should they get so hot when the bike is not even running. Robert
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Richard Hyatt
Senior Member Joined: 14 Oct 2019 Location: Dorset Status: Offline Points: 1097 |
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Any ht coil will be using/consuming around 5 to 8 amps, so this is why they get warm.
The internal resistance dictates the current used using ohms law , which I can't draw here sorry. Amps , volts,resistance relationship V= AxR And any configuration of these 3 12v= A? X 1.5 ohms As Dacia says you do the maths If the bike is sitting with the key on , that's why they're getting warm , riding along in the wind and rain takes the heat away.
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Online Points: 17641 |
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A "standard 12v coil would probably be 3.5 ohms. At a nominal 12v, it will consune about 3.5 Amps. At a running voltage of 14v, it will consume 4 Amps. The 5 ohm coil @ 12v will pass 2.4 Amps, and at 14v - 2.8 Amps. So the 5 ohm coils would run cooler. The heat produced will be directly proportional to the current consumption.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Dave P.
Senior Member Joined: 12 Jan 2015 Location: Northants Status: Offline Points: 5573 |
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This is interesting. So what factors determine the ideal coil resistance requirement for a given vehicle?
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TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.
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