Re: John Deere 445 Electrical problems

Posted by txblu on October 12, 2004 at 10:47:01 from (199.46.199.231):

In Reply to: Re: John Deere 445 Electrical problems posted by Teej on October 10, 2004 at 23:44:01:

Teej speak truth.

A full sized 40 hp tractor takes bout 100A to start (average). Gonna guess a 20 hp tractor will take about 1/2 or so of that (50A). You have a 12v battery. If the circuit resistance is only 1 ohm, 50A x 1 = 50 volts..(You don't have but 12v to spend...just lost 50)....even at the stated book max of .1 ohm it's still 5 volts.

5 volts off a 12v system is a loss of 40% in voltage. You are approaching the drop out voltage (if not there) of your solenoid. The clicking you hear is it releasing then (voltage rising due to load being released, to 12) on the way to 12 it passes the energizing voltage of the solenoids coil (CLICK) it closes, but in closing it loads the battery (trying to turn the starter) and the needed voltage shows up acrosss your "dirty parts" so the voltage falls (across the solenoid) back below "hold in" value and it drops out (CLICK) and on.

Mark

Follow Ups:

• Re: John Deere 445 Electrical problems fred emerson 18:20:28 10/12/04 (1)
  • Re: John Deere 445 Electrical problems txblu 10:14:18 10/13/04 (0)

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