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Startus interruptus fix caused other problems. Advice needed please!


Jim in NZ

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Kiwi Roy,

Yeah, I have no idea what my inrush current numbers are, I'll take your word for it that they are "high" for a few milliseconds.  My D'arsonval meter goes as high as 50amps and has no circuit protection (stupid me).  Anyway, I got to thinking my old meter could be giving erroneous readings so i hooked up my digital vom that has a 10 amp fuse for meter protection and jumped the starter again,  The current draw was 4-5 amps once the display semi stabilized and the starter was cranking the engine.  

There is something else you could try with your Ammeter, disconnect the main positive lead to the solenoid, now your inrush current will last as long as the spade connector is powered up, because the starter armature will never see +12 Volts it effectively keeps the heavy current (Grunt Coil) in circuit. The 15 Amp fuse will blow in < 1 second so be prepared to replace that with a 20.      .......Nope, ain't gonna do it, no need to, I have no high draw, starter cranks fine.  And yeah, I know what happens if I disconnect the heavy gauge battery HOT at the starter and engage the pull-in coil....high draw until I de-energize circuit.  Plus with my luck lately I'd booger something up and need a new solenoid.

Tell me.....If you disconnect the 16ga primary feed to your starter solenoid on your bike and jump battery pos. to the male spade terminal on the starter solenoid, what is the solenoid current draw a few milliseconds after the starter ramps up to what sounds like normal cranking rpm?  Mine is 4-5amps.  If guys are getting 10a, 15a, 20amp draws, you got problems, that is all I'm saying.   

Art

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8 hours ago, guzziart said:

Art,

Tell me.....If you disconnect the 16ga primary feed to your starter solenoid on your bike and jump battery pos. to the male spade terminal on the starter solenoid, what is the solenoid current draw a few milliseconds after the starter ramps up to what sounds like normal cranking rpm?  Mine is 4-5amps.  If guys are getting 10a, 15a, 20amp draws, you got problems, that is all I'm saying.   

Art

As soon as the solenoid closes the main contact the Grunt coil is effectively switched out of circuit so all you will see is the holding coil current, It should be higher. Typical holding coil resistance is 1.25 Ohms, (12 Volts / 1.25 Ohms = 9.6 Amps)

Assuming you are measuring the current with the starter working hard, it's pulling 150 - 200 Amps pulling the battery Voltage down below 9 Volts, perhaps even as low as 6. If you measure the Voltage across the coil that will back up your current readings. e.g.  (9 Volts / 1.25 Ohms = 7.2 Amps) (6 Volts / 1.25 Ohms = 4.8 Amps)

Note: While the solenoid is engaging the gear the load on the battery is quite light (<60 Amps) so the Voltage will be almost 12 Volts, its only once the gear is in place the main contact switches power to the motor the load goes over 100 Amps.

It takes the solenoid 15 - 50 milliseconds to engage the gear and close the main contact.

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Yes, I think you've summed it up very well!

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