# 6 volt to 12 volts



## Rob30 (Nov 2, 2004)

I just bought a hassey harris 35 combine. It runs great but is not chargeing. From what I understand the generator has probably lost its magnatism, because It is not charging. I have converted tractors before to a chevy alternator, but not a 6 volt tractor. 
So I am going to see if I can fix the gnerator first. If I can what will happen if I run a 12 volt battery for this season? There are no lights, just the ignition and chargeing systems. 
If I have to change the generator out I will replace with a chev alt. What else do I need to change? I assume a 12 volt coil. I was told the points and everything would be fine.
One advantage of changing it over would be that a 12 volt battery is easier to find. Olus it would be easier to add electronics, such as lights. I do alot of work in distant fields, so I may be driving home at night.


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## sammyd (Mar 11, 2007)

all you need is a ballast resistor before the coil then you can leave the rest alone.


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## agmantoo (May 23, 2003)

Rob 30
I would be more inclined to think the points in the old regulator are oxidized thus causing the system not to charge. The cover on the regulator can be removed and the points can be burnished. It is best not to use sandpaper on the contacts.


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## vallyfarm (Oct 24, 2006)

Don't need a ballast resistor, get a 12 volt coil with internal resistor...will say so printer on coil. BUT, you will need to switch pos ground that your tractor came with to neg ground for the alternator to charg properly. Go to YTMag.com and you can find several wiring schematics for those old tractors.:thumb: Switching to 12 volt and then switching back to a 6 volt ignition systom kinda defeats the whole purpose of fixing a charging problem. REWIRE THE WHOLE TRACTOR !!! A very easy thing to do. This will eliminate any shorts or breaks or rust or contact problems that may be all or part of the problem. The 6 volt starter is stronger than a 12 volt starter, so no problems there. (twice the volts means 1/2 the amps.) Mike


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## HermitJohn (May 10, 2002)

Delco 10si or 12si have to be easiest thing in world to wire. Lets say you have no wiring whatsoever. You have installed the alternator, made necessary brackets, installed belt, etc. you run at least a 10 gauge wire from the B+ terminal to the positive battery terminal. You run short wire from the F (field coil) terminal on the alternator to the B+ terminal on alternator. You mount a $2 cheapo "side marker light" to your "dash" or where you can see it and and run light gauge wire from one of wires on light to your ignition switch. You run a light gauge wire from the other wire on light to the D+ terminal on the alternator. 

You turn on your ignition switch, the marker light lights (like idiot light would in a car). You crank your engine, it starts and voila the marker light goes out and the alternator is charging. Some alternators are better than others, I've had some the light wouldnt go out until you got over 800rpm. I've had others, when engine starts, the light goes out immediately.

And yes for ignition, you need wire from positive battery termnal to ignition switch or B+ terminal on your key switch if you are using a universal key/ignition/starter switch and wire from ignition out terminal to ballast resister and from ballast resistor to + terminal on 12V coil. And wire from from - on coil to your distributor. If you have problems with cold starting, you can rig it so 12V comes from starter solenoid to ignition coil while starter is cranking. Then the ballast resistor circuit cuts in when engine starts and starter stops.










Oh and if you didnt know, you can buy a 6V voltage regulator that replaces the 12V voltage regulator inside the Delco 10si alternator. So you have a 6V alternator!!!!


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## Rob30 (Nov 2, 2004)

Ok, so lets say I fix the combine the way it is. I find a 6 volt battery. Do I wire it in with the positive going to the grounding wire? I don't really understand how the positive can be the ground.


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## Ross (May 9, 2002)

How does it run if its not making electricity? Does it run off the battery until its dead?


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## woodsy (Oct 13, 2008)

Rob30 said:


> Ok, so lets say I fix the combine the way it is. I find a 6 volt battery. Do I wire it in with the positive going to the grounding wire? I don't really understand how the positive can be the ground.


Not sure if all the 6 volt systems had a pos ground but my old JD M does. Works fine that way.


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## HermitJohn (May 10, 2002)

Rob30 said:


> Ok, so lets say I fix the combine the way it is. I find a 6 volt battery. Do I wire it in with the positive going to the grounding wire? I don't really understand how the positive can be the ground.


Is it a positive ground system? There were both 6V negative ground systems and 6V positive ground systems, when 12V systems came into being, there were both 12V negative ground and few 12V positive ground systems. People today dont think about positive ground systems cause last of them were on few foreign cars in 1960s. I dont think any vehicle with an alternator had a positive ground system, at least not on any car, light truck, or farm tractor. There may have been some large specialty positive ground alternators???

If its positive ground then yes the ground wire goes from the positive battery terminal to frame/engine block. Pretty simple, for a DC circuit, you need a positive and a negative. There is no rule as to what is positive and negative. So ground can be positive and the "hot" wires can be negative.

Your combine may well be positive ground. I vaguely remember an old Massey Harris 444 tractor that I bought couple decades back was 12V positive ground with a non functional 12V generator. Had to rewire it when I converted it to 10si alternator.


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## HermitJohn (May 10, 2002)

Ross said:


> How does it run if its not making electricity? Does it run off the battery until its dead?


Once started a gas tractor engine would only need power enough for ignition. There are no "accessories" unless you need/use lights. You could run it long time on fully charged battery. I remember once long ago I was headed home, it was long distance and it was getting dusk. Discovered my alternator was shot and if you turned on any accessory, car would sputter and attempt to die. But there was enough battery to power the points and condenser ignition, with everything else off. I kept wondering if I was going to get pulled over by cop, cause then car for sure would never restart, as cop would insist I turn off my engine while he talked to me and I'd have huge tow bill. Or it could get too dark to see to drive without lights. But I made it.


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## woodsy (Oct 13, 2008)

I knew someone smarter than me would show up and explain that positive ground business.

Thanks John !


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## Windy in Kansas (Jun 16, 2002)

I have driven a vehicle over 100 miles at highway speed on only battery power and used lights part of that distance. Ignition itself takes very little power. The occasional brake lights and turn signals use doesn't take much either.


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## sammyd (Mar 11, 2007)

Ross said:


> How does it run if its not making electricity? Does it run off the battery until its dead?


That's how my old WD works.


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## agmantoo (May 23, 2003)

Rob30
Just a suggestion. Time is critical when combining a crop and the equipment needs to be dependable. Use the schematic an wire to combine according to the schematic provided above. Borrow a 12 volt battery and use it in the combine while needing to run the machine. By doing this the combine will crank readily with the 12 volts and should remain dependable during the harvest. The cost of making the conversion should be about the same as trying to find a 6 volt battery that will probably go dead between seasons as the combine will have limited use.


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## Windy in Kansas (Jun 16, 2002)

agmantoo said:


> Borrow a 12 volt battery and use it in the combine while needing to run the machine. By doing this the combine will crank readily with the 12 volts and should remain dependable during the harvest. The cost of making the conversion should be about the same as trying to find a 6 volt battery that will probably go dead between seasons as the combine will have limited use.


Rob will still need to switch to a 12 volt coil or simply add a resistor to the 6 volt coil.

If it were me up against a time issue I would add the resistor and just use a 12 volt battery and charge it whenever I had the chance. I did that with my truck but also changed all lights. It was a couple of months before I felt I had the time and proper weather to make brackets, etc. and install an alternator. I pulled the battery from ??? something that wasn't being used and carried a charged spare when I drove any distance. Never did have problems doing it this way. Sort of like with an electric car, just takes some trip planning. 

If you add an alternator one thing to keep in mind is whether the belt pulleys will match for size of belt width.


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## agmantoo (May 23, 2003)

Windy in Kansas

Yes I agree with you. That portion was an oversight on my behalf.


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## Windy in Kansas (Jun 16, 2002)

agmantoo, you are knowledgeable and I figured you just failed to mention it, but since bots search the posts and they hit the web I thought it should be pointed out for the benefit of others.


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## Ross (May 9, 2002)

I understand how an engine runs off a battery, but as Rob said he needs to find a new battery. I am assuming his original one is toast. So how does it run if its not charging AND the battery needs replacing?


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## Windy in Kansas (Jun 16, 2002)

Ross said:


> How does it run if its not making electricity? Does it run off the battery until its dead?


Yes, that is correct.


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## Rob30 (Nov 2, 2004)

The battery was fully charged when I put in in. The combine did not come with a battery, the previous owner put a 12 battery in it to show me how well it ran. 
I probably have a 12 coil in the garage. I think I will put one in and run the 12 volt battery. I am sure I can run most of the afternoon on a charged battery for this season.


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## Ross (May 9, 2002)

Do you have a deep cycle battery you could use or are you sacrificing an old one?


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## ace admirer (Oct 5, 2005)

lots of people just restore the 6 volt system, they worked great in their day...


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## HermitJohn (May 10, 2002)

ace admirer said:


> lots of people just restore the 6 volt system, they worked great in their day...


And 6V batteries were lot cheaper in that day. And cars/trucks were all 6V too. On something like a combine that you use maybe one month a year, battery will go bad in that 11 month standby period unless you have a 6V maintenance charger hooked to it that automagically turns on and off as needed. 

I dont even use my tractor enough to keep 12V battery charged. So I dont have a battery just for tractor, tractor shares pickup battery as needed. But if tractor were 6V, there wouldnt be anything to share a battery with.


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