12 volt conversions switch or not to switch

When converting to 12 volts,if I switch to negative ground,do I have to change the wires on the coil?Also what is the opinion of people,switch or leave original.I have a WD and a WD45 that I am fed up with the six volt system.I know this probably has been posted here before but even when I was in school I didn't like to pay attention,any input would be appreciated,Tony

Mine are all on six volt with proper size cables and I don't have any problem with them.

 If you switch to 12 volt you will have to change the coil to a 12 volt unit anyway so you can go with either polarity at that point. You will also have to swap your 6 volt generator for a 12 volt unit or an alternator. Also light bulbs, otherwise they will be very bright for a very short time!!LOL

Thanks for the input guys,the  biggest problem I have is the connections not staying clean,seems they forever have to be cleaned on a six volt system,I am going to find some really heavy gauge  cable for the wd and try it first before converting it,thanks again,Tony

Farm and Fleet has the proper cables on hand for both the WD and WC.  Don't forget the ground wire has to be large too.  I prefer the strap type for a ground.

i switched both my wd 45's over to 12 volt and rewired them years ago and no problems yet and im not looking back. i had the generators switched over instead of going with an alternator, i like the original look...Jb

I've had good luck with some types of battery post protectant. I've use mainly to types one is a brush on looking gel and the other is a spray can that looks a lot like red paint when it is applyed, but don't harden like paint. This will help keep the connection between the post and cable clamps. I perfer the the spray can to the brush on, it dries but don't harden (dust don't seem to stick to it), but is harder to get complete coverage. The brush on you can get better coverage, but like I said the dust and every thing sticks to it.

When I buy an old tractor, if the 6v battery is good and it starts fine I leave it 6v. As soon as the 6v goes to giving me trouble it's going to 12v.

Don't forget to swap the wires on the back of the amp gauge in addition to the coil when changing polarity. Otherwise it will work backwards.

One big reason to the 12V conversion is the battery itself, you can find 12V batteries everywhere and they are fresh , as a 6V may have sat oround for 6 months or longer sulfateing the plates while it sat waiting for a new owner.

We offer a 12V conversion for the early Tractors, but I always ask our customers what are you using the Tractor for? You may not need to convert. If its a work horse that's used around the farm constantly, and has a few extra lights needed for early evening work and implement hookups, then it may be advantageous to upgrade to 12V. If its a hobby tractor, or a tractor used around the farm on occasions with the other work force of equipment, and doesn't need to have exta lighting or accessories on it, then leaving it 6V would work fine. Its really up to the individual on how the machine is used. The two biggest excuses I hear at our shop is the engine doesn't turn over fast enough or it ain't charging. Most of the time its a 65+ year old Starter motor or Gennie that's pretty tired out, after its 52 rebuilds with bushings, brushes, and bearings and never an arm put in either. As the guys mentioned, correct size cables are super important, along with a little more attention to cleanliness to keep the 6V system in tip top shape. Most of my Tractors are still 6V. My IB is converted to 12V w/alt. because of the extra accessories I have on board that I use. Gerald made a good point with upgrades to the 6V system which increases reliability to the system. Electronic ignitions, voltage regulators, etc are nice upgrades to the 6V system. Yeah, their not OEM, but they help, and can be hidden if the OEM look is important to you. 6V Batteries are becoming a problem with sitting around on shelves for long periods of time as mentioned that's for sure. Just because it's new to you, doesn't mean its been "freshly" built. If you do find a Battery dealer that moves quite a few Batteries, and rotates his stock, you're much better off purchasing a much fresher 6V Battery from that person, that once  put into service will last you quite a few years. The 6V Battery in my B went 7 years to my surprise before I renewed it just this year. Battery tenders help emensely with keeping sitting Batteries active to keep sulfation down, (especially during the winter months) which applies to 6V or 12V , and getting more life out of a unit. Bringing them inside to a warm basement or garage helps to. Whatever you decide for your particular application, some of the newer upgrades really enhance an old system, and in my opinion is a plus...

Brian: Some 6 volt generators *can* charge a 12 volt battery.  A 3-brush generator can sometimes be adjusted to put out enough voltage.  Your mileage may vary. And contrary to what I'm seeing in a few posts, generators (and alternators) do NOT put out a constant current. Generators tend to put out a voltage that is somewhat dependent on the RPM. The regulator puts out a constant voltage. 13.8 to 14.4, dependent on temperature, is ideal. The amps will depend on the state of the battery's charge. A fully charged battery with 13.5 volts applied will "float."  It will neither gain or lose a charge.  It will not boil either. Alternators tend to put out higher voltages at lower RPMs.  This is why they are better suited for charging. If you are going to switch to 12 volts and you want a more authentic look of your tractor's year, go to the bone pile and get an old 12 volt generator and regulator.

I switched most to 12 volts because I got tired of dealing with those fat azz battery cables. I am a modernizer. Whatever is most common and convienient is what I want. Out here in the sticks, it is hard enough just dealing with common stuff. And for the record I have never changed polarity or voltage on a coil.

Fact is the 3 brush generator IS a constant current machine. The position of the third brush sets the amount of armature reaction that adjusts the field strength to hold the current constant. At low speeds the current and voltage does fall off for battery charging. That characteristic is why the 3 brush generator will take on an 8 volt battery without adjustments and sometimes a 12 volt battery.

With constant field current/voltage all simple (not three brush) generators and alternators have output voltage EXACTLY proportional to shaft speed. So one way to get more voltage (sans regulator) is to change the pulley and turn the dynamo faster. When the field current is supplied by the output voltage, the output voltage rises faster than the shaft speed until the field core is saturated, then it goes back to directly proportional to shaft speed. I've run a 6 volt generator as a motor (makes a decent 1/3 hp motor) on 6, 12, and 24 without destroying it.

Long ago, before college I didn't realize these effects and my dad and I rewound a 12 volt generator armature and field with half the size wire, twice the turns to run 24 volt DC surplus radio equipment. 4 or 5 years later in college taking a DC machinery course I learned we worked too HARD and all we needed to do was spin it faster with more field excitation. But my dad had been a motor repairman and actually doing the rewind was super education for me. Later when consulting in electrical accident litigation (after four years of college and 8 years of graduate school and then industrial experience) it was fun to answer the cross examining attorney's question on where did I learn about motors, to say, "At my father's knee. Then I went to college."

I have found few college graduates who have rewound motors and who have designed and built transformers which I have.

I still like university libraries and my library card is active though its been 35 years since I last graduated.

Gerald J.

Yup, pretty much the same current independent of load from a few volts until the armature core saturates. The output voltage can still depend on shaft speed, but the third brush regulates the current and since a battery being charged will take almost any current (up to 100s of amps) when the charger can supply it, its the constant current characteristic of the 3 brush generator that will charge hard. Unfortunately for the battery the 3 brush generator will also over charge the battery. That's why drivers of 30s vintage cars with 3 brush generators turned the headlights on during the day to divert current from overcharging the battery. That's why vintage AC tractors connected the field current resistors to the head light switch. To try to set the charging current to the load.

Constant voltage generators make lousy welders too, constant current works far better in making a consistent arc current despite variations in arc length.

Gerald J.

Tony, I see the response has left you speechless, LOL.

Previous owner switched my D14 to 12volt and it starts awfully good.