Recently I have been getting solenoid chatter on my Ford 641 tractor when I try to start it. (I converted it to a 12 volt system years ago.) I have found the problem to be apparently poor electrical contact between the + battery terminal and the battery cable. A black coating appears on the post and where it makes contact with the cable end. I scrape it off, reconnect and I can start the engine. This happened a year ago, again yesterday AND today. (I have not cleaned the post and cable end yet for today.) What are the cause(s) for this chatter?
Solenoid chatter
- Thread starter MillWeld
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WranglerX
Super Member
Low voltage because of corrosion causing resistant between battery post and cable..
Suggest scrupulous clean up of battery post and cable terminal (shine with scotch bright pad or sand paper), use baking soda wash to neutralize any acids on surfaces and coat contact areas with a oxidation preventive grease.... A oxidization preventative grease keeps oxygen and acids out of connection and prevents corrosion.........
I use this particular grease on all my batteries and never have any problems with corrosion on battery terminals....
Dale
Texasmark
Elite Member
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- Ford: '88 3910 Series II, '80 3600, '65 3000; '07 6530C Branson with FEL, 2020 LS MT225S. Case-IH 395 and 895 with cab. All Diesels
Cause of the chatter is the drop out of your battery voltage. Senario goes like this: You turn the key/push the start button on an electrical system feeling full battery voltage. The starting solenoid has full voltage and energizes as expected. Once energized the engine wants a couple hundred amps from the battery to roll the starter. This amperage, when sucked through a bad connection causes a voltage drop across the bad connection part which is subtracted from the available voltage holding the starter energized.....like drop out voltage for 12v solenoids is like 9 volts.
Once the voltage across the solenoid coil drops below that level, the solenoid can't remain energized and it drops out opening the current feed to the starter.....whereupon the circuit voltage pops back up with zero current flowing to the starter and the solenoid re-energizes...etc. etc.
Same thing happens with a slightly charged battery and good electrical connections in the high current path.
Once the voltage across the solenoid coil drops below that level, the solenoid can't remain energized and it drops out opening the current feed to the starter.....whereupon the circuit voltage pops back up with zero current flowing to the starter and the solenoid re-energizes...etc. etc.
Same thing happens with a slightly charged battery and good electrical connections in the high current path.