One wire alternator

[rrlund]

I know, here we go again. It gets beat to death once a month. I've looked at wiring diagrams until my eyes are blurry. When I look at the wires on the tractor and can't trace them, I'm frustrated to no end. I've got that British Oliver 500 gas. It has a Lucas generator. Everything is Earth and all that crap instead of ground, field and what not. I'm ready to toss in the towel and put a one wire mini alternator on it so the battery will quit going dead sometimes and other times not.

It doesn't have a solenoid, just the big button like older American tractors. As all of you know with those set ups, there's just a battery cable to one post and a cable to the starter from the other post. On the post where the cable goes that comes from the battery, there's a hot wire going to the key switch. If I just hook a wire to that post and run it to the post on the alternator, will that work? Work as in charge the battery? I checked my tractors that have alternators from the factory and the big post on the alternator is hot even with the key off. Never mind the gauge for now, it doesn't work anyway, just like that Lucas generator.

 

[used red MN]

On the post where the cable goes that comes from the battery, there's a hot wire going to the key switch. If I just hook a wire to that post and run it to the post on the alternator, will that work?

Yes, but as you alluded to it will not show the charge on the ammeter. It could be possible that something in the voltage regulator is sticking and running down your battery. With the generator gone you have about an 80 percent chance that this sticking issue in the regulator will not be a problem. Usually when that is happening the field in the generator is being energized. You can easily add a voltage meter. The voltmeter would just need to see power from the key when it is on to give a volt reading. If you remove the ammeter to install the volt meter the wires on the ammeter will need a screw ran through them to connect them together tightly and then tape them well.

 

[rrlund]

Yes, but as you alluded to it will not show the charge on the ammeter. It could be possible that something in the voltage regulator is sticking and running down your battery. With the generator gone you have about an 80 percent chance that this sticking issue in the regulator will not be a problem. Usually when that is happening the field in the generator is being energized. You can easily add a voltage meter. The voltmeter would just need to see power from the key when it is on to give a volt reading. If you remove the ammeter to install the volt meter the wires on the ammeter will need a screw ran through them to connect them together tightly and then tape them well.

The diagrams that I'm seeing show the hot wire coming from the key, to the amp gauge, then to the alternator from the other side of the gauge. When I turn the key on, I have power to one side of it, but not coming out the other side. I only have power going in one one side when the key is on anyway, so if there's supposed to have power to the alternator all the time, that's not going to cut it. I'm wondering, should I go buy a new gauge and wire it to the other side of the key switch, then to the alternator from the other side of the gauge? Doesn't seem right to me that there should be power running through that gauge all the time. That's how somebody's diagram looked here on YT though in one that I found with a Google search.

 

[scootergmc]

I know, here we go again. It gets beat to death once a month. I've looked at wiring diagrams until my eyes are blurry. When I look at the wires on the tractor and can't trace them, I'm frustrated to no end. I've got that British Oliver 500 gas. It has a Lucas generator. Everything is Earth and all that crap instead of ground, field and what not. I'm ready to toss in the towel and put a one wire mini alternator on it so the battery will quit going dead sometimes and other times not.

It doesn't have a solenoid, just the big button like older American tractors. As all of you know with those set ups, there's just a battery cable to one post and a cable to the starter from the other post. On the post where the cable goes that comes from the battery, there's a hot wire going to the key switch. If I just hook a wire to that post and run it to the post on the alternator, will that work? Work as in charge the battery? I checked my tractors that have alternators from the factory and the big post on the alternator is hot even with the key off. Never mind the gauge for now, it doesn't work anyway, just like that Lucas generator.

Someone makes a kit for these with a harness.... maybe it includes a diagram and all that: https://hitepartsonline.com/product...amp-alternator-conversion-kit-with-tach-drive

 

[Jim.ME]

The diagrams that I'm seeing show the hot wire coming from the key, to the amp gauge, then to the alternator from the other side of the gauge. When I turn the key on, I have power to one side of it, but not coming out the other side. I only have power going in one one side when the key is on anyway, so if there's supposed to have power to the alternator all the time, that's not going to cut it. I'm wondering, should I go buy a new gauge and wire it to the other side of the key switch, then to the alternator from the other side of the gauge? Doesn't seem right to me that there should be power running through that gauge all the time. That's how somebody's diagram looked here on YT though in one that I found with a Google search.

I'm confused, and maybe a bit dense here, you said you had a Lucas generator, which would have a separate regulator, and you were about to toss in the towel and put a one wire mini alternator on it. In this post, an hour and a half later, it sounds like you have installed the alternator and are having wiring trouble with the alternator. Is this correct?

First question is what alternator are you using? And are you certain it only needs one wire?

In general, the one wire on a one wire alternator is direct battery power from the battery cable post of the starter solenoid/relay. It has too much current to be run through the key switch. It can be run through an ammeter if you chose. As used red MN posted if you decide to use a voltmeter that would have one terminal powered from the key switch, the second terminal gets a wire that goes to ground. The alternator output wire does not connect to a voltmeter.

If you have a hot wire from the key to one terminal of your current ammeter and it does not show power on the second terminal of the ammeter when the key is on, your ammeter is broken, replace it. When you replace it do not run a wire from the key. It needs a 12-or 10-gauge wire from the solenoid. then from the other terminal to the alternator. All the loads (power to the key switch, lights, etc.) should also be on that second terminal. Yes, that keeps power through the gauge all the time. If you want to shut that power off, you need to install a battery disconnect switch.

 

[olddavid]

It doesn't hurt the ammeter to have the power running through it. That's what it was designed for. Don't run the main starter current through it. That should run directly to the starter through a heavy-duty switch or heavy-duty solenoid contacts. There shouldn't be any power going through it when it isn't running and the key is off.

 

[rrlund]

I'm confused, and maybe a bit dense here, you said you had a Lucas generator, which would have a separate regulator, and you were about to toss in the towel and put a one wire mini alternator on it. In this post, an hour and a half later, it sounds like you have installed the alternator and are having wiring trouble with the alternator. Is this correct?

First question is what alternator are you using? And are you certain it only needs one wire?

In general, the one wire on a one wire alternator is direct battery power from the battery cable post of the starter solenoid/relay. It has too much current to be run through the key switch. It can be run through an ammeter if you chose. As used red MN posted if you decide to use a voltmeter that would have one terminal powered from the key switch, the second terminal gets a wire that goes to ground. The alternator output wire does not connect to a voltmeter.

If you have a hot wire from the key to one terminal of your current ammeter and it does not show power on the second terminal of the ammeter when the key is on, your ammeter is broken, replace it. When you replace it do not run a wire from the key. It needs a 12-or 10-gauge wire from the solenoid. then from the other terminal to the alternator. All the loads (power to the key switch, lights, etc.) should also be on that second terminal. Yes, that keeps power through the gauge all the time. If you want to shut that power off, you need to install a battery disconnect switch.

No, I haven't bought an alternator yet. The auto parts store sells a lot of stuff to the dirt track guys here and they sell a little mini, one wire self exciter to those guys. That's what I'm figuring to use.

For several years, this thing has had a problem with the battery going dead. In 2024, Memorial Weekend before a show, another club member was here and we were messing with it a little bit looking for shorts.. The gas tank is in the way of seeing any of the wiring on the back of the dash. You can kind of get a hand up in there a little ways, but that's it. We took the nut off the key switch and tried to drop it down to get a look at the wires on the back of it, but the wires were too short, so we put it back in. It was good the rest of the summer and stayed up all winter. It started right up this spring. I figured we must have moved a wire that was shorting out or something.

So this summer, it was good until 4th of July. We ran it in a parade, backed it on the trailer and when I got home, the battery was dead. I charged it, took it on a drive the next weekend and when we stopped for ice cream, it was dead as a door nail again. I pulled the hood and gas tank the day before yesterday, hoping I'd find something obvious. Just tape up a wire or replace it, but I can't find anything, unless it's inside of a harness or something. I give up. I'll put one of those minis on it, paint it green and hope nobody who cares notices.

 

[Gene in Mi]

I post #3 your test of power at the ammeter indicates that it is bad. Charging current passes through the ammeter to charge the battery. You can keep your generator if you replace the amp meter.
Heck, jumper the gage with a heavier wire or just put both wires on either post to bypass the meter. It sounds like you have been getting by without that meter showing charge current. Now it sounds like it sometimes doesn’t pass charging current.

 

[rrlund]

I post #3 your test of power at the ammeter indicates that it is bad. Charging current passes through the ammeter to charge the battery. You can keep your generator if you replace the amp meter.
Heck, jumper the gage with a heavier wire or just put both wires on either post to bypass the meter. It sounds like you have been getting by without that meter showing charge current. Now it sounds like it sometimes doesn’t pass charging current.

When I say amp meter, I'm using it as a generic term. It's British. It doesn't show charging amps. It's a "Battery Condition" gauge. All it shows is how many volts are in the battery, theoretically, but I don't think it even does that. It used to show about 10 volts with a full charge in the battery, never moved, not is shows about 8. It's probably wired different than an amp meter because it only shows battery voltage. If the battery is up when I want to start it, that's good enough. I don't need to know how many amps it's charging every minute. I've heard that the reason the British drink warm beer is because Lucas makes refrigerators.

 

[Jim.ME]

No, I haven't bought an alternator yet. The auto parts store sells a lot of stuff to the dirt track guys here and they sell a little mini, one wire self exciter to those guys. That's what I'm figuring to use.

For several years, this thing has had a problem with the battery going dead. In 2024, Memorial Weekend before a show, another club member was here and we were messing with it a little bit looking for shorts.. The gas tank is in the way of seeing any of the wiring on the back of the dash. You can kind of get a hand up in there a little ways, but that's it. We took the nut off the key switch and tried to drop it down to get a look at the wires on the back of it, but the wires were too short, so we put it back in. It was good the rest of the summer and stayed up all winter. It started right up this spring. I figured we must have moved a wire that was shorting out or something.

So this summer, it was good until 4th of July. We ran it in a parade, backed it on the trailer and when I got home, the battery was dead. I charged it, took it on a drive the next weekend and when we stopped for ice cream, it was dead as a door nail again. I pulled the hood and gas tank the day before yesterday, hoping I'd find something obvious. Just tape up a wire or replace it, but I can't find anything, unless it's inside of a harness or something. I give up. I'll put one of those minis on it, paint it green and hope nobody who cares notices.

If you have a problem "inside a harness somewhere", installing an alternator may not fix anything.

You posted this: "When I turn the key on, I have power to one side of it, but not coming out the other side. I only have power going in one one side when the key is on anyway, so if there's supposed to have power to the alternator all the time, that's not going to cut it. I'm wondering, should I go buy a new gauge and wire it to the other side of the key switch, then to the alternator from the other side of the gauge?"

Were you describing how your current ammeter is working? Or how you think it should be? Are you testing with a voltmeter or test light?

As I posted before, if your current ammeter has power on the terminal the power supply wire is hooked to and no power on the second terminal, the ammeter is no good and needs to be replaced. That could be causing some of the problems you are having if it is losing continuity through it on an intermittent basis, it could affect charging and it could cause power loss to the switch.

Post one or more of the electrical drawings you say you are looking at.

Do you have manuals with the original wiring diagram(s) for your tractor to see if things are correct after all these years?

 

[Gene in Mi]

When I say amp meter, I'm using it as a generic term. It's British. It doesn't show charging amps. It's a "Battery Condition" gauge. All it shows is how many volts are in the battery, theoretically, but I don't think it even does that. It used to show about 10 volts with a full charge in the battery, never moved, not is shows about 8. It's probably wired different than an amp meter because it only shows battery voltage. If the battery is up when I want to start it, that's good enough. I don't need to know how many amps it's charging every minute. I've heard that the reason the British drink warm beer is because Lucas makes refrigerators.

Ahh.
Yes they are wired differently. Voltmeter can be wired to any point where it can read battery voltage that is turned off with the key. Amp meter MUST be wired with heavy wire between the charging unit and the battery, because it carries full charging current.

 

[rrlund]

Like I just said in another reply, it's not an actual ammeter, just a battery condition gauge. The only wires inside of a harness are the ones to the generator and regulator. I was going to pull all of that out and just run one new wire to the alternator. I'm just using a test light. With the gas tank off, I can't start it to test amperage anywhere.

The post on the back of the key switch that has power when I turn the key on has two wires. One to the battery condition gauge, to call it what it is, and one to a fuse panel. What do you think about this? I take the wire to the gauge off, put it on the hot post on the switch, buy a new ammeter, hook that wire to the new gauge and run a new wire to the alternator from the other side of the gauge? Take off the regulator, pull out all the wiring for the old generator and regulator?

 

[Jim.ME]

When I say amp meter, I'm using it as a generic term. It's British. It doesn't show charging amps. It's a "Battery Condition" gauge. All it shows is how many volts are in the battery, theoretically, but I don't think it even does that. It used to show about 10 volts with a full charge in the battery, never moved, not is shows about 8. It's probably wired different than an amp meter because it only shows battery voltage. If the battery is up when I want to start it, that's good enough. I don't need to know how many amps it's charging every minute. I've heard that the reason the British drink warm beer is because Lucas makes refrigerators.

Sorry I missed this before; I was typing my reply to one of your earlier replies. Using ammeter as a generic term for the gauge only confuses things as an ammeter and voltmeter operate differently and are wired differently. Current for the system does not pass through a voltmeter.

 

[rrlund]

Here's a link to one of the old posts. You'll have to scroll down a ways. JMOR posted the diagram.

S

Thread 'How do I convert a new Delco-Remy to 1 wire alternator?'

Nov 19, 2013

How do I convert a new Delco-Remy to 1 wire alternator?
This is for my Ford 850 conversion from 6 volt to 12 volt
I connected a wire from spade post #2 to alternator Battery post to make a 1-wire alternator.
I ran a wire from alternator to battery post on 3 post solenoid where the battery thermal positive side is.
I ran a wire from solenoid battery post to off side of switch.
Tractor runs, but trying to figure if alternator is charging.
I have this light (idot) that is supposed to light up the 14.0 light if alternator is charging it does not.
Does this alternator have to run 3000...

• Shealray
• Replies: 36
• Forum: Tractor & Farm Talk

 

[Jim.ME]

I prefer having a voltmeter (battery condition gauge) to having an ammeter. How many times have you read posts here where someone with an electrical problem was told to use an ammeter to test with compared to using an ammeter?

The drawings in the thread you linked in your last post appear to be for Delco 3 wire alternators, not one wire alternators. Someone was wanting to convert a Delco 3-wire alternator to a one wire alternator, not convert from a generator to a one wire alternator as you want to do.

Here is one for a Farmall with a one wire alternator conversion. If you don't want an ammeter, as shown on this drawing, the wire would go right to the alternator battery post. You would add a wire with a 30-amp breaker or fuse to power the ignition switch and headlights, similar to the wire to the ammeter in this drawing. A battery condition indicator (voltmeter) can be powered from the same terminal of the switch that powers the ignition.

If you can provide an original wiring diagram for your tractor it can be modified for you to show a one wire alternator.

Edited to attach the missing drawing.

 

[Gene in Mi]

Like I just said in another reply, it's not an actual ammeter, just a battery condition gauge. The only wires inside of a harness are the ones to the generator and regulator. I was going to pull all of that out and just run one new wire to the alternator. I'm just using a test light. With the gas tank off, I can't start it to test amperage anywhere.

The post on the back of the key switch that has power when I turn the key on has two wires. One to the battery condition gauge, to call it what it is, and one to a fuse panel. What do you think about this? I take the wire to the gauge off, put it on the hot post on the switch, buy a new ammeter, hook that wire to the new gauge and run a new wire to the alternator from the other side of the gauge? Take off the regulator, pull out all the wiring for the old generator and regulator?

Your suggestion should work. IF the wires are big enough for full charging current. 10 gauge minimum.

 

[buickanddeere]

You have to trouble shoot , looking for paths for current to chassis . That are not supposed to occur . Moving a fuel tank is not trouble shooting .

 

[Jim.ME]

Is this the same Oliver 500 you were having wiring issues with, in the spring of 2015? If this is the same tractor, from that thread and with the issues in this thread, swapping to an alternator and doing a full rewiring would look like a good path forward. I mentioned modifying the original wiring diagram for you, however reading through 2015 thread it already has had several modifications (such as it now uses a key switch and solenoid for the starter and gauges have been replaced) that need to be confirmed to make a diagram for you. It looks to me like just scabbing in an alternator is not a long-term cure of the electrical problems. Here is a link to a thread you had about it back then.

April 2015 Oliver 500 thread

It would seem like this sketch would get you going with a one wire alternator. I would remove all the old wiring (outside of maybe the lights) and install new wires. 10 or 12 gauge between the solenoid and alternator and 10 or 12 gauge between the solenoid and breaker. For everything else 14 gauge will be fine.



If you want/need to run a tractor for troubleshooting when the fuel tank has been removed, it is common to use a small temporary tank. I have one I made from a 2-1/2-gallon metal gas can that has supply and return fittings so it can be used for gas or diesel engines. Some people use old lawnmower tanks, some solder a fitting in the lower side of a gallon size metal can.

 

[rrlund]

Is this the same Oliver 500 you were having wiring issues with, in the spring of 2015? If this is the same tractor, from that thread and with the issues in this thread, swapping to an alternator and doing a full rewiring would look like a good path forward. I mentioned modifying the original wiring diagram for you, however reading through 2015 thread it already has had several modifications (such as it now uses a key switch and solenoid for the starter and gauges have been replaced) that need to be confirmed to make a diagram for you. It looks to me like just scabbing in an alternator is not a long-term cure of the electrical problems. Here is a link to a thread you had about it back then.

April 2015 Oliver 500 thread

It would seem like this sketch would get you going with a one wire alternator. I would remove all the old wiring (outside of maybe the lights) and install new wires. 10 or 12 gauge between the solenoid and alternator and 10 or 12 gauge between the solenoid and breaker. For everything else 14 gauge will be fine.

View attachment 134185

If you want/need to run a tractor for troubleshooting when the fuel tank has been removed, it is common to use a small temporary tank. I have one I made from a 2-1/2-gallon metal gas can that has supply and return fittings so it can be used for gas or diesel engines. Some people use old lawnmower tanks, some solder a fitting in the lower side of a gallon size metal can.

Ya, that's the one. I had forgotten that somebody had even put a solenoid on it. I took it off back then and went back to the big push button that it was supposed to have. We're on the same page about stripping out the old wiring and replacing it with what's actually needed for an alternator. As far as a long term solution, I'm 70. How much time do I have left? This tractor is just a show tractor anyway, it doesn't do a lick of work. Even then, it get's left home sometimes. I have a 500 diesel orchard that the wife drives on rides and a 600 diesel that I'm pretty proud of that I like to use on drives. All of these in addition to two Oliver 66s and a Super 55 that go to shows and plow days. So this 500 gas isn't a real high priority, it's just a rare little tractor that I want the battery to be up on when I get on to start it.

 

[Jim.ME]

Ya, that's the one. I had forgotten that somebody had even put a solenoid on it. I took it off back then and went back to the big push button that it was supposed to have. We're on the same page about stripping out the old wiring and replacing it with what's actually needed for an alternator. As far as a long term solution, I'm 70. How much time do I have left? This tractor is just a show tractor anyway, it doesn't do a lick of work. Even then, it get's left home sometimes. I have a 500 diesel orchard that the wife drives on rides and a 600 diesel that I'm pretty proud of that I like to use on drives. All of these in addition to two Oliver 66s and a Super 55 that go to shows and plow days. So this 500 gas isn't a real high priority, it's just a rare little tractor that I want the battery to be up on when I get on to start it.

Long term or short term, if you want it dependable the fix is the same as far as I see it.

Strip the old wiring off, install the alternator, install new wiring and a battery disconnect switch on the negative battery cable. Turn the battery disconnect off when it is setting to eliminate the chance of stray discharge and fire from a short.

Here is my sketch with the push button switch instead of a solenoid for the starter.