12 Volt Conversion

Can anyone assist me with information on converting my 1951 TO 20 to a 12 volt charging system?

I would strongly recomend a 12 volt generator and regulator from a newer tractor instead of an alternator. Real strong possibility that you won't have to change any existion wiring and for sure no mounting brackets to make the change.

Thank you for your assistance. It seems the TO 20 is a different kinda Tractor. The folks at the yesterdays tractor is telling me there are no converdion "kits" for that model tractor. I guess that would have made it too easy. Anyway, it is going to get converted. I always try to learn from other folks that may have all ready done this kinda thing before rether than re-envent the wheel.

Unless keeping the appearance original is desired, there's NO reason to use a generator and carry forward all the 6 Volt generator problems into a 12 Volt setup.

A modern alternator is MUCH more reliable and charges more, especially at low engine speed.

if there's no premade kit, then you have a couple options.

1, get the gen converted to 12v and a regulator to match, wire it up, and change the coil and lamps.. as Bob points out, the 12v gen will be like the 6v gen.. low to no charge at idle. If this suits you.. go for it.. you won't have any brackets or belts / pullies to change.

or make yer own brackets and put a cheap delco 10si alternator on there.. might have to swap pullies and belts.. and still need the new coil and lamps. go with a 3 wire setup vs a 1 wire.. on a 3 wire, loop #2 over to charge stud, and run #1 thru a 194 marker lamp to the same side of the key switch as the coil is on.. key on = lamp on. once tractor starts and is at 400 rpm or so.. lamp goes out indicating charging is occuring.. ammeter should verify this.

hook charge stud on alt to the wire that used to run to the bat terminal on the old ( un needed ) vreg.

soundguy

I don't understand. Unless you want to connect a radio or some other 12V device, why would you convert a 6V to a 12V?

Every one of my 6V tractors is still a 6V tractor. Even if I let them sit for months, they still fire right up.

BUT

You need to have good battery wiring. I use welding cable for battery cables when I make my cables. Clean grounds and you are in business.

To elaborate on Soundguy's sound advice, the reason to change is economics, if your 6 volt system has bad components, newer 12 volt internally regulated alternators cost about 1/3 less than the oem generator unit rebuilt, and that don't include the regulator! I always like to adapt the alt to the existing brackets, as housings on GM 1 wire alts are plentiful. Just get the belt running straight and true, and use the smallest diameter pulley you can find. A good alternator rebuilder could set you up with a low rpm excited unit, or just remember to rev the motor up, right after starting, then slow it back down, and it'll keep charging.

in the interest of ergonomics, a 3 wire alt actually usually costs less than a 1 wire.. due to the regulator module .. and a 194 trailer lamp is a couple bucks.

in reality.. 3 wire is AS easy.. works better ( excites on its ow at low rpm ) and is cheaper.. truly a win win situation.

i've actually seen some old low revving tractors that didn't make enough rpm to excite a 1 wire.. ( jd B comes to mind.. )

soundguy

A little more info. David..................

http://www.ytmag.com/articles/artint131.htm

Ok.. now I have a question, since I like the idea of the "light" in the charge system.. Do you still ground the light? Seems to me you'd have to for it to work, right?

Also, in all I have looked up it says I need a diode on that wire to prevent back-feeding. Will it matter where I put the diode? (like alternator/ignition switch side of the light?)

I don't mean to seem dumb on the subject.. Just last time I wired in a alternator I had a draw on my battery as well as other minor problems I never totally figured out, so I "engineered" so it would charge, but still always had a dead battery, unless I unhooked a cable.

If it helps any it's a Massey Harris 33..

And as I have it figured..
I hook alternator charge terminal to + side of ammeter..
Ignition switch to - post on ammeter (to which I have coil, light switch, and now wire to #1 post of alt.. When I had this before, the tractor would never shut off, but never had the diode.. unhook the #1 and it would shut off.)
Wire to #1 has the light and diode (but do I wire the light both posts to this wire, or will it need a ground? I visualize it as having to be grounded)
Wire to #2 is a jumper to charge terminal

Sound correct? If not, what am I missing/ doing incorrectly?

Thanks in advance,

Brad

Use ONE of the following in the "excite" lead... 10 Ohm, 10 Watt resistor, "idiot light" (194 lamp or equivalent) OR a diode. You only need ONE of these devices in the circuit.

Ok, so then if I go with the light (which napa offers this cute little idiot light thing... bought it a while back for something else but it never panned out right.. so here is the perfect place for it) do I ground it, or hook both sides of it to the excite wire? (this particular light has 2 wires, one hot, one ground, not a self grounding unit)

Again, I don't mean to seem stupid about it.. just want to be sure I do it right, being the tractor I'm going to do it on is starting to be prepped for paint, and I'd hate to have to tear back into it once it's all done after finding out it don't work correctly

Thanks again
Brad