4020 Gen Light 12v Conversion - Update #2

As previously recommended from prior postings, I hooked the Gen light up to the 12v alternator's "s" terminal. Light on with key. Started tractor.....gen light stayed on with alternator not charging. Jumped between "S" and "IG" terminal, light went out with alternator charging as previously noted in posting. However, alternator quit charging and light went on as soon as jumper wire was removed.

I then tried to insert the 10ohm resister at the idiot light across the wires feeding the light. With resistor, light came on with key but very dim. Started tractor and light got brighter and alternator did not seem to be charging. Resistor did not seem to solve any issue.

So am I just forced to live with no working light with this Nippo alternator or would a different size resistor make any difference? If not, I may just leave the Nippo until failure and replace later with Delco (i.e. so gen light will function). Any further thoughts or am I out of luck??
 
You were already told the Nippo would not
operate the light. Adding a different resistor
will not change that.
Don't expect that Nippo to fail soon unless you
mess it up switching wires. They are a much better
alternator than the others and should last thousands
of hours. If you want the light to work use a Delco.
 
The onboard idiot light with or without additional resistors (if and where required) is one method for indicating charging (plus initial excitation) on some Delco SI family of internally regulated Alternators. The alternators excitation circuit requires x amount of initial current which passes to and through an incandescent "idiot light" (if so equipped) providing charge indication.

However since you already have that Nippon Alternator I would just install a voltmeter instead to provide a degree of charge indication. A full charged 12 volt battery at rest would read around 12.6 volts (subject to temperature) but if a good working alternator is engaged it should rise to at least 13 and up to 14 + depending on RPM and voltage regulation.

John T
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top