12 volt conversion problems

I did a 12 volt conversion on my wd45 this week and when I tried it out today everything worked fine except for the tractor would not quit running when the ignition swith was turned off.  I wired in a diode just like I was told.  It was a 50 amp diode in the wire between the the ignition switch and the internal voltage regulator on the alternator.  I know I had the cathode turned the right way too because I tried it both ways.  If anyone could help me with this problem I would greatly appreciate it.  Thanks.

unless the you have the terminals mixed up on the ign. switch. the voltage has to be coming from the alt. disconnect the lead from the alt. and see if it still does it. i think you can get away with not hooking up that wire off of the alt. as it is excited by the wire hooked to the bat. the light was to tell if it was charging or not. hopes this makes sense.

Looks to me like the alternator feeds directly to the coil.  Try switching the wire to the other side of the switch

Been a while since I did one and memory is not what it should be but wiring looks OK and the only way it can backfeed the coil is through the diode, which means it is bad. This can be checked by removing it and placing a test light in that circuit. I have never been able to figure out the diode deal, a light bulb and socket is cheaper to free (if you keep some junk around) self diagnostic, and cannot back feed. For those who dont want to look at an idiot light you simply hide it.

Diode will work fine. A 1 amp/50V diode will do the job yer' looking for. Also, a 3.0 ohm coil would be a better choice than a ballast resistor that's shown in the diagram, being Mother Nature plays havoc with the ballast resistors. If you intend on using an Ammeter, choose the 60/60 sweep version in lieu of the OEM 20/20. Most "SI" series Alternators can put out way more amperage than that 20/20 can handle if a problem should occur on board somewhere, which makes it the weak link in the system. A Voltmeter is a safer way to go if so desired. If using a Voltmeter as I use in my 12V conversions, wire it to the aft side of the Ignition switch, this way you can use it as a junction for the Alts output circuit and not worry about a parisitic draw on board the Tractor while not in use with the key in the Off position. In my systems, the key switch controls all on board power. Use a 10 gauge wire for your output circuit.  In the diagram, #2 circuit from the Alternator is used as your "sense" circuit to tell the regulator whats needed to satisfy the Battery and normal system load.. HTH

A good web links is worth a 1000 words....

http://www.kansasselectproducts.com/12V%20Conversion%20Guide.htm

Are you using a single wire exciting alternator?  I am using the old style three wire alternator and this diagram worked for me...
   

still does not settle the issue. does the wire #1 or white wire on bee's diagram need to be hooked up to anything? reliable alternator rebuilder that gave me my diagram said it was optional as in remember but my memory is getting foggy. does an ign. switch give voltage to the acc terminal when key is on? i never checked.

yes dad, you need both wires. the #1 wire is 12 volt excitation to make the alternator kick in and charge... the #2 wire should be always hot and jumpered to the lug on the back of the alternator that is connected to the ampmeter- then battery.

Gerald, I respectfully disagree. 

But don't believe me, listen to a gauge expert. 

http://www.autometer.com/tech_faq_answer.aspx?sid=1&qid=5


The amp capacity of an 8 gauge wire is much higher than an 18 or 20 gauge wire.  This is what has the propensity of causing a fire.  An voltmeter keeps the amperage away from the confines of the dash.  And as such its very simple to fuse the low current going into the dash, not so with 60+ amps to an ammeter, that is live all the time. 

I have seen a fire do just to corroded/bad connections at the ammeter gauge itself, never seen one do to an voltmeter.

A charging system due to a bad regulator, can charge below normal voltage, say at 12 volts, and then you are sulfating the plates, but you would never know with an ammeter.  You know if the battery is sulfated with a voltmeter, especially if its badly sulfated, it would indicate high voltage, ie 15.5~.  Also you can do a quick charge test with a voltmeter that is impossible with an ammeter.  If the vehicle has been run recently(or battery charged) in the past 12 hours but not within say 3 or 4 hours.  Without starting the vehicle, turn the headlights on for a minute or two to remove any surface charge.  Then turn them off and read the voltmeter.  If at 12.7 your battery is good, if below 12.4 it not fully charged, and has issues somewhere.  If your alternator is not keeping up or is bad you voltage is going to drop off, below 13.6 after a few minutes. 

Warning the voltmeter  applies to three wire alternators which is the bases of this thread.  One wire alternator(piss poor choice) and generators, can benefit from an ammeter as they can discharge at lower rpms and you won't know it. Really both would be more helpful in these systems.    A 3 wire alternator compensates for rpm in it regulator circuit. 

It also appalls me that neither of the circuit diagrams have fusible links or main charging system fuses!  The fuse in the second diagram while not a bad idea is really not protecting the main part of the system. And the second diagram doesn't have a diode or idiot light to prevent possible back feeding, and thus battery discharge when the tractor is shut off