Converting Your Old Allis-Chalmers "G"
Cultivating Tractor to an Electric Vehicle

Installation Instructions
(Estimated Time: under 4 hours)
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The electric motor, as it comes out of the box.

The smaller pulley fits on the motor shaft like this.

What pulley and bushing look like when they are screwed onto the motor shaft

Now, this is the fun part!
1) Take your motor, and set it up verticially, as in the picture to the left.

2) Set the smaller of the two plates your machinist made over the shaft. You are going to screw that plate on to the face of your motor, and your bolts can't stick up any, so you'll notice that you have tapered bolt holes... you want the WIDER part of the hole to face out, away from the motor, and the narrower part touching the motor. This way, when you put the bolts in, they will "hide" inside those holes and not interfere with later steps.

If your machinist did a good job, you will find that this plate fits very snugly around the raised area at the base of the spinnable silver shaft, and you will find this to be very satifying.

3) Twist it around a bit and make sure that the four tapered holes in the plate line up with the four bolt holes on the face of the motor.

4) You should have a small rectangular piece of steel... that you can sort of tap into the groove on the silver spinning shaft of the motor. It should fit just perfectly and snuggly. It should have come with bushing that you ordered, that we are about to put on in step number 6 below... maybe they are in the same package. It's small!!

5) Slide the smaller of your two pulleys on. It says P16H150-110 8 on it. It has a narrower area inside with half screw holes and a wider open section. You want the NARROWER section with the half screw holes to be closer to the body of the motor. (see picture to the left).

6) Now slide on your bushing! It has "#1108 7/8 PRC L"printed on it. Keep the writing facing away from the body of the motor. It will only slide onto the shaft in one orientation because of the rectangular piece of steel you put on earlier. You'll probably have to tap it a bit to get it on.

7) Lift up the pulley sprocket so it's about 5/8" above the plate that is resting snugly on the motor. I just did this by eye, you can too... You have some room to play with.
Push that bushing down by tapping it with a screwdriver or whatever until it is nice and snug with that pulley... and the whole unit should, again, end up about 5/8" above the plate. Now put your screws in. They have an embedded hex head in them. You'll need a 1/8" allen key wrench to do it. Line it up so that your screws can go in any of three spots (there is only one way to do this). For some reason I only have two screws. I put them either side of the split in the bushing (see picture at left) and I tightened them decently snugly.

8) Now attach the motor plate to the motor using the four tapered hex head capped bolts (3/4 long x 3/8) that you bought. Put them on quite tightly!

Attaching the pulley assembly to the clutch disk (we have an extra ring in this picture).
Okay, now it's time to put the big pulley assembly together: IMPO. NOTE: If you ordered the parts from Niekamp Tool Company, this step is ALREADY DONE FOR YOU at the shop! Just skip ahead to the next step! The following instructions are ONLY for people who machined the plates and pieces themselves at home.

You need to gather the larger pulley (it says P32H2002517 on it). And the large ring that looks like a washer, as well as the needle bearing (11/16th by 15/16ths by 3/4 (Jh1112)) and the bushing piece that your machinist made for you.

You also need to grab your old tractor's clutch plate! You know, the one I told you to save when you were taking the tractor apart!

1) First put together the bushing and bearing pieces into the bigger pulley.

2) Now attach the pulley assembly to the clutch disk using four screws and the big silver ring washer. In the picture to the left, note that we have an EXTRA thinner washer ring... your part won't need that, we've now implemented that piece into the bushing in the diagrams you'll give to your machinist (or order from Herman).

3) Okay, here's the big deal! That PTO Shaft protrusion in the center of your clutch disk has to be PERFECTLY aligned in the center of the pulley assembly! Herman made a little tool to get this perfect, and he'll send it to you for a few bucks+shipping (you have to send it back to him, though) I tried to fake it, and it didn't work.

Not to be obvious, since you can see it in the picture, but do make sure that the stick-out portion of your clutch plate is sticking out AWAY from your pulley!

You will use four 1.5 inch long by 5/16 inch coarse threaded bolts to attach that outer ring to the bushing on the center of the pulley, making one solid unit. Put those on tight, because you don't want it to slip or move around over time.

Again, this step is ONLY for those who have machined these pieces themselves. If you ordered them Pre-made from Niekamp Tool Co., you do NOT NEED to bother with this step or ordering any jigs, etc. Just skip to the next place .

Big pulley screwed on to the center of the plate. Note it's screwed on to the side that has the nuts welded on to it, and the pulley is against the plate (with the zirc fitting sticking through the hole).

Another image of the big pulley screwed on to the center of the plate

The four screws that hold the big pulley on, and the zirc fitting sticking through the center whole.
Okay, now attach this new larger pulley assembly and clutch disk to CENTER of the larger plate. The picture at the left was taken just after I did it. Note that the pulley side of the unit you just made (or received in the box from Herman already screwed together) should fit against the plate. What you can't see from the picture, though it will be obvious in real life, is that there are four screw holes, and a place for the zirc grease fitting to slip through. It needs very little greasing and not so often.

Make sure that you attatch this assembly to the side of the plate that has the nuts welded on to it!!! That's not so obvious and easy to mess up, so be careful!

Setting the plate on the motor

The four screws holding the motor on to the main plate. The holes are much larger than the screws so you can move the motor around.

Now we are ready to attach the motor to the big plate. This is a 2 person job. I recommend that you set the motor up on something, because, as you'll see, you have to attach some bolts in from underneath (the side that the motor is coming from), so sitting it up on a milk crate like we did here in these pictures, made it easier to get to.

I am missing a picture here, but it's easy... before you can attach the motor to the plate, you need to first attach your SMALL plate to the motor. This is very easy, the key element is that the bolts that you use to screw that plate on to the motor MUST fully fit within the recessed bolt-head-holes, so that that smaller plate can fit flush against the larger plate later.

Just to be overly explicit, when you look at your smaller plate, you will notice that the open holes are drilled out wider on one side than the other. You want those WIDER holes to be facing away from the motor, towards you. You have to use your hex-key bolts, because you won't be able to fit a wrench inside of that hole. Hopefully that makes sense!

Okay, NOW you can refer to the picture on the left. Once your smaller plae is tightly screwed on to the motor, you can set the larger plate on top of that! Don't screw it on yet though!

I am missing another picture here, but it's also very easy, you need to slip the belt over the 2 pulleys. First put it on the larger pulley, slipping it over the clutch plate, and THEN slip it over the smaller pulley.

NOW you can attach your screws! They go in from "underneath", that is, from side of the plate that the motor is on. That's why I wanted you to set the motor up on a milk crate. Those bolts screw in to the four welded-on nuts on the big plate. Just put them on loosely for now, and Don't forget the washers.

As you can kind of make out in the bottom picture to the left, the holes that these bolts go into are much larger than the bolts themselves, that's o we can move the motor around and in that way tighten the belt! So, go ahead and slide the motor around until you get that belt pretty snug on it's teeth. Don't overtighten it, you aren't trying to tune a guitar string, it should just be snug. NOW tighten those bolts on so that they won't let the motor slip and loosen the belt!

Okay, now we attach that plate/motor assembly to the back of the tractor. You are almost at the point of having a working tractor!

As you can see from the picture on the left, We set the milk crate down under where the motor was going to go because this assmebly is heavy. It took all three of us to set it on, and it took several tries, because you sort of have to "jimmy" it on so that your clutch plate fits back on to its old familiar place slipped over the sprocket heading in to the transmission.

Have the bolts handy, so as soon as you've got it "sorta" on, you can use the bolts to pull the plate in the rest of the way. Having done this MANY times now, I can tell you this is the ONLY way to get such a heavy plate on!

Now you are ready for the electrical components!

First, let's make the all the cables you will need. Find the cable and cable ends (also called cable lugs) in the box from Electric Vehicles of America. You have to cut the cable to the right size, stip off about 1/2" of insulation from either side (enough to fit in the cable ends) and then crimp the cable ends down.

First, cut the cable. You can use a hack saw, or... I put the cable in a vice, and attached a metal disk-blade to my circular saw. That made very short work of the cutting process.

      -Make three (3) pieces of cable that are exactly 2'2" (two feet-two inches) long.
      -Make two(2) more pieces of cable exactly 1'10.5" (one foot-ten and a half inches) long.
      -Make one (1) piece of cable 1'5.5" (one foot-five and a half inches) long.

      -Make two (2) super-short pieces of cable... Just big enough to fit terminal ends on either side.

Now, strip the ends about 1/2 an inch (check the length with the cable lugs you received, there are different types, and you don't want to have extra metal showing.

Permanently fix the cable lugs on one side of each of your wires. Attach the other side loosely. Afix the cables to the tractor as noted below. Note the alignment of the cable lugs, and THEN smash them down in that same alignment. Does that make sense? I hope so. It takes a bit longer, but if you do it this way, your cables won't be twisted at all, reducing torque on the terminals of the components and batteries.

You can buy a cheap little tool to correctly and permanently smash the cable ends onto the cables. I hope I don't get in trouble for saying that I just smashed the cable ends flat with a hammer the first time I did this, and... they are working great. It is essential that the contact between the cable and the ends is EXCELLENT, not just "good". If you do a bad job, do it again -even if you have to go to the auto shop and buy more cable and ends. There are a LOT of amps flowing through these wires, so a loose connection is going to heat up and will very possibly melt... Certainly it will pop and hiss and your tractor will not run very smoothly.

All of this electrical work is very simple, but must be done perfectly neatly and securely and it should be checked often and repeatedly throughout the season because your tractor is going to be bouncing and jiggling and things do loosen up! It takes less that 60 seconds to check the obvious connections for tightness. We made a sign for our tractor that we used to leave on the seat to remind us. It saves trouble (not serious trouble, but trouble and confusion nonetheless) down the road.

I'm going to repeat that above advice, but I wanted it to be playing in everyone's head as they are building.

Okay, set your cables aside, and let's bolt more components onto your tractor.

Battery Platform (not fully assembled)

Arrange the batteries on the platform as shown here.

Attachment points for battery platforms.
Okay, first let's put the batteries on. Most of you will have purchased your machined parts from Niekamp Tool Company, and they nowinclude a battery box platform (without the plywood). All that remains for you to do is cut a piece of plywood for the batteries to sit on that fits into the welded metal frame they made. You can see in the diagram to the left where the battery platform bolts onto the tractor.

To the left, you can see the plywood battery platform we cut out (one battery has been removed, and not all cables are afixed.) Note that we drilled two holes to feed the cables through to the motor and controller. You don't have to do this, but you should. It makes it so much neater (though I have to admit this picture isn't very flattering!)

Once the plywood platform is on, set the four 12 volt batteries on the platform as shown in the configuration diagram to the left. The platform should be big enough to hold 6 eight volt batteries as well.

If you machined your own parts, then obviously you will need to make a little platform for the batteries to sit on yourself. This is VERY easy to do.

Take a look at the picture to the left. It shows the existing spots you can use to mount your battery box. You are looking at the tractor from underneath the battery box we built.

The left hand side of the picture is the front of the tractor, and that left arrow is pointing to what used to be the mount for your old gas tank. The right hand arrow is pointing towards the two bolt holes you would use to attach a rear implement. There are plenty of other ways you could configure the battery box, this is just one way.

You can tell we welded angle supports and the square frame to hold the batteries, but for our first prototype tractor we bought angle steel from Home Depot that had lots of pre-stamped holes in it. We cut four pieces down to size, attached them to the four connection points, bolted on another four pieces to make an upper frame, and set a plywood box on top of that, and it held up for three years with relatively few problems.

For everyone:
The batteries weigh 80lbs each. In the years that we have been running this, we have NEVER affixed the batteries to the box, or even attached the box to the metal frame. In the version you are seeing here, we don't even USE a box, just a flat piece of plywood, and it hasn't caused us any trouble. 320 lbs of lead just don't move around much! We built a wooden cover box to go over these batteries just to protect them from the elements, but recently someone suggested that we just put an appropriately sized rubbermade tub over the batteries... that would be even easier.

Optional Electric Hydraulic Motor Installation
This is an optional step, but I'm glad we did it. For the first year, we used the existing hydraulics on the tractor. Not everyone's "G" tractor even HAS hydraulics. Some of you have big long levers to raise and lower your front implements, and they work great for you.

We had a hydraulic motor on our tractor, and although the electric conversion didn't impact our existing hydraulic pump, it was really slow and annoying (just because it was so old, I think). So we purchased a 12 volt hydraulic pump with an attached 3-way joystick switch , (the cheapest, smallest one,) from the Northern Tool catalogue ( They don't call it a hydraulic pump, they call it a "12 Volt Power Unit", and I'm sure lots of places on the internet sell them.

We removed the original old battery box from the right hand side of the tractor (you know, the battery that used to start your gasoline engine). We screwed a square piece of 2x8 onto the mounting holes for the battery box and then we bolted the new electric Northern Tools hydraulic pump onto that piece of wood. (You can't bolt it directly to the tractor because the mounting holes for the original "G" battery box don't line up with the mounting holes on the hydraulic pump. Using the wood makes it easy and you don't have to weld anything onto the tractor!)

This placement of the pump (with the attached joystick on top of the pump) means our hydraulic controls are close and handy right next to your seat! It cost under $300, and the electrical installation is a no-brainer (just two wires running to a battery in the back).

This is an easy thing to add on in the future if you feel it's worthwhile. We do like ours. One important point if you DO decide to do this, is that the hydraulic motor is a 12 Volt component! So... you would NOT want to run it off all 4 batteries (putting out 48 volts) or you will burn it out!

We just chose one of our four batteries and run it off that one battery. Of course that is not how you SHOULD do it, that is a "Farmer Hack" but we find that it doesn't matter at all. Yes, that battery must be running down a little faster than the others, but the truth is that we only operate the hydraulic pump for literally 1 second bursts at a time, and then a very finite number of those 1 second bursts in a given day, so... I haven't seen that it is noticeably exausting the battery. I do change the battery that it's running off of a few times a season, though....

If you want to do it right, Electric Vehicles of America sells the 48volt-12volt converters you need. I'll write about this again at the end of this installation section when we talk about powering the Contactor.

There are 3 of these spacers to keep the controller up off the plate. If you purchase a different controller, it's easy to install it on a piece of plywood, and then attach the plywood to the plate, but you'll still have to use the three spacers to keep the plywood spaced off the plate (or you'll interfere with the pulley screw underneath).

The installed controller. Ignore the wiring for now.

OKAY! There are only three more pieces to bolt on to the tractor! Let's start with the most complicated, the Controller.

You may not have the same controller we list in the "Parts Ordered" page. They keep improving them, and prices keep changing up and down... don't worry about it (just make sure you did get the weatherproof version!). The basic configuration of what wires go where is consistent and well labelled on the two controllers we've seen. If you don't have the same labels, you should read the directions. I have to admit I couldn't understand the directions on our controller, so Bob at EVA had to interpret them for me. Now it works great and I understand why.

If you have a different controller than I list here, you may also find the mounting holes don't match up with the mounting holes we've given you on that back motor plate! Don't panic! It will just take a LITTLE bit of creativity on your part...

No matter which controller you have, as you face the rear of the tractor, the controller mounts on the LEFT hand side (see picture at left).

You will see there are three holes in your plate. Those holes are threaded so you can actually screw a bolt into them. Mount your controller so the terminal ends are facing UP. If you have our exact controller, you will see there are four mounting holes on the sides of the controller. We are only going to use three of them. We are also going to use the three little spacers (see picture at left). You need the spacers because the pulley screws are underneath the controller!

Now, in case you don't have our listed controller, see if the holes line up anyway. Maybe you will be lucky! If they don't line up, can you drill new holes through the aluminum plate on the bottom of the controller? (Obviously WITHOUT breaking through the case). If you can, then great. Otherwise, take a piece of plywood and drill holes through that to line up with the holes on the plate of your tractor. Now drill new holes so you can bolt (not screw) the controller to that piece of plywood! Easy!! You will need to use the spacers between the plywood and the metal plate, but you DON'T need spacers between the controller and the plywood.

Installing the Contactor
Now attach the "Albright Contactor".

Why do they call this a "Contactor" instead of a "Relay". I don't know. It is just a big Relay switch. By applying 12 volts of power to the relay, you turn the switch "ON" and the full 48 volts can flow to your motor.

You may ask, (like I did) "Why do I need a Contactor? Why can't I just turn a normal, manual switch on and off?" Or, you may be cheap (like I was) and say, "Oh... I'll just turn the tractor on and off by touching the wires together. What's the big deal? And I'll save $55!"

I must admit, it's been very exciting to learn why this is a bad idea. I'll spare you the science, but basically, because this is a low voltage DC system, the CURRENT flowing through these wires is very high! (That's why we need to use such thick wires.) If you tried to use a normal switch to turn this on and off, or if you just tried manually connecting and disconnecting the wires where they are supposed to go when you wanted the tractor to start up, there would be a blinding flash of light, a puff of smoke, and metal would literally VAPORIZE before your eyes! WOW! Could this be on-farm proof of E=MC2? I think so!!! When you are able to see again, call all your friends and tell them you are a genius.

We don't do these sorts of fun experiments anymore, but you can tell that we DID at one time because there are lots of chunks of metal missing from the ends of our cables. Our original set of batteries (which were destroyed) show where we melted through the plastic. What expensive fun we had in those early days. If only we were rich enough to afford it.

You can save yourself some money in batteries and wire by just imagining the fun we had and using an Albright Contactor from the beginning. Hopefully you got the "all weather" version. If you didn't (like us), you can make an "all weather" case by dropping your contactor into a capped piece of pvc pipe and caulking around the hole where the wires go in and out! Then, where your mind clears from all the toxic PVC fumes, you can still call your friends and tell them you are a genius.

The Contactor screws in to threaded holes that are supposed to be drilled near the center of that back Motor Plate, in between the controller and the motor (See picture to the left). Don't worry if you ended up getting a DIFFERENT contactor than we did. The best thing to do though would be to drill and tap new bolt holes in that back metal plate in configuration with the holes on the Contactor you purchased. Don't attach this very tightly, because you will need to futz with it a little bit when you attach the wires as you'll see in a few minutes.

Here is how we screwed the "Potbox" into the metal frame supporting the battery box.

This is how the metal rod screws into the original throttle on the tractor. Although we used a new shiny metal rod here, you could just as easily use the original throttle rod once it is bent straight and cut a little smaller.

Now attach the Speed Controller (Officially called the PB-6 Potbox).

This item attaches to your tractor so easily that you will wonder if the AC-"G" folks back in 1947 were planning for these new millenium electric conversions. First, if you ordered the machine parts already made, you have it REALLY easy. The Potbox just screws right in to the bottom of the battery platform -right into the metal. If you made your own platform, just drill and tap two holes so that you can screw this item roughly in line with the existng throttle control on your tractor (the lever on the left hand side, under your seat.).

Niekamp Tool company will send you a shiny metal rod with a hole in it to attach the Potbox to your existing under-the-seat throttle control. If you machined things yourself, you can just use the rod from the original tractor! Bend it straight(er), cut off the excess and wire it on to the end of the PotBox switch.

Try it out, and make sure you connected it the right way. When you push FORWARD on the lever under your seat, it should pull the Potbox lever forward, (allowing you to drive forward at increasing speeds) When you push backwards, it should allow the Potbox lever to spring back to it's original resting place, bringing you to an easy stop.

It's that easy! Now let's connect the wires!

Wiring Diagram for all big wires.
Note the the placement and labelling of terminals on your controller and motor may be DIFFERENT than what you see here. Look and follow the labels as written on your components, rather than just automatically attaching the positive battery terminal to the far left Controller terminal (for example)!!
Also, note the black wire between A1 and S1 on the motor... see the description to the right.

Final Wiring
At this stage you are just a few minutes away from driving around the yard on your electric tractor.

Note of caution
I need to start by repeating what I wrote above. This is going to feel like such an easy job, but establishing good strong connections, and no loose wires, is essential to safe and happy electric tractor operation. Check your connections often (like every day before you take off) to make sure they haven't loosened up.

Installing shrink tubing
Bob at Electric Vehicles of America is now sending out shrink tubes to go over the lug ends of your wires. You could also use electrical tape. The point is, you want to minimize the open surface area of your wires. The shrink tubing is a breeze, you just slide it on, and then heat it up by quickly waving a propane torch under it (not so it melts, just enough heat that it starts shrinking.) We didn't have this when we built our tractor so I don't have a picture, but it seems like a good idea. Do this step after you have figured the alignment of each of the wires and have smashed down the loose lug side.

Below are more detailed written instructions of exactly what you are hooking up and where. To the left is a diagram. Please do read the descriptions below.

#1: Take a 1'10" piece of cable. With a permanent marker write Batt + on one side and B+ on the other side. Facing the back of the tractor, one side goes on the left-most POSITIVE battery terminal. The cable fits through the hole you probably drilled in the bottom of your battery platform and attaches to the big terminal marked B+ on your controller. When you have the alignments right, smash the battery lug all the way down on the wire (obviously remove the cable from the tractor for this step!) and shrink wrap or tape the unnecessarily exposed parts of the wire and go ahead and tighten it down on top of the battery, but NOT on the B+ terminal of the controller because we are about to attach another wire there.

#2: Attach a 2'2" cable from B+ on your controller to S2 on your motor. Once you have the alignment of the second cable lug correct, remove it, smash it down, shrink wrap or tape the ends and tighten back on correctly on both sides.

#3: Attach a 2'2" cable from M- on your controller to A2 on your motor. Once you have the alignment of this third cable's lug correct, remove it, smash it down, shrink wrap or tape the ends and tighten both sides.

#4: Attach a 1'10" cable from B- on your controller to either large terminal ends of your Albright Contactor. Once you have the alignment of this third cable's lug correct, remove it, smash it down, shrink wrap or tape the ends and tighten both sides.

#5: Attach a 2'2" cable from the open terminal on your Albright Contactor to the Negative terminal of the right-most battery. Once you have the alignment of this third cable's lug correct, remove it, smash it down, shrink wrap or tape the ends and tighten both sides.

#6: Note the black wire in the diagram to the left between A1 and S1 on the actual motor. They must be connected together, but on our motor they are so close that we couldn't actually make a cable small enough to fit! While you could do multiple wraps of exposed copper wire, bolted on, we actually cut out a piece of 1/8th inch copper, notched it, and then bolted that between the two terminals. It looks very neat.

Now it's time to connect your batteries to each other. Because the batteries are all on one plane, alignment of your cable ends isn't going to be a problem. So you can go ahead and smash down all the remaining cable ends and shrink wrap (or tape) them up to protect the unnecessarily exposed parts.

#7: Starting with the left most battery, attach a super-short cable from the (open) negative terminal to the positive terminal of the battery to the right.

#7: Now attach a 1'5" cable from the open negative terminal of that second battery to the positive terminal of the the 3rd battery to the right.

#8: Now attach a super short cable from the open positive terminal of that third battery to the negative terminal of that last battery.

That's it! You're done, and you shouldn't have any more big cables left!

Let's attach the small wires coming off your Potbox

Start with the grey wires coming off your Potbox. Crimp "Quick Disconnect" terminals (from your local auto-parts store or Radio Shack) of the size appropriate to fit onto the small terminal ends of your Controller.

Looking more closely at those small metal contact points on your controller . The terminals are numbered on both our Alltrax controller and our earlier (unknown brand) controller. Attach the small black wire from your Potbox to terminal end #3. Then attach the small white wire from your Potbox to terminal #2.

Now take a short piece of wire and crimp on a quick-disconnect terminal to one side. Attach the other side to the big B+ terminal (or directly to the positive lead on your battery if there is more space for that) and slide the quick-disconnect onto the small terminal marked #1. When adding this small wire, it's essential that you don't diminish the contact between the battery cable end and the controller (or battery).

NOTE: Obviously, you should read the instructions for your own controller. I am telling you how we installed two different companies' controllers, but I don't know what other controllers look like. I've written the details here because it is LIKELY you will end up with our same Controller componentry. Even if you don't, hopefully it will help you to understand whatever you do purchase, because this was a very complicated step for me.

What I've written here is the easiest way to approach the pot-box/controller wiring, but you may want to read through your controller manual (even if you have the same ones we have) to see if you'd like to do it another way.

For example, we don't actually run positive power from our battery directly to the #1 terminal of our controller as I've written above. Instead, we run the power through the Potbox. If you look more closely at your potbox, you will see that it also has some small terminal ends sticking out. I hesitate to give exact details here because (again) I worry that your components may not be exactly the same as ours, but you can read the instructions (or use the resistance/continuity tester of your Voltmeter) to learn which two of those leads give you a simple "ON-OFF" switch. When the Potbox is in the fully relaxed position, they are off and discontinuous. If you move the lever even the slightest bit forward, they become "connected" and the switch is "ON".

We connect it that way so that even if power to the tractor is left on, unless the Potbox is activated (by pushing the throttle lever under your tractor seat) no power will run to the controller. It's not necessary, but nice to engage this feature.

The last item is the On-Off switch . You should read the instructions for your Contactor, because, as with the Controller, I don't have a lot of experience with different companies' contactors!

The basic concept is simple though and will be consistent with any Contactor you buy. It's just a big relay switch, so you need to run 12 Volts of power to make the switch "close" and allow the massive amperage (and full 48 volts) to power your motor.

You can mount the on-off switch wherever is convenient for you. I'll leave instructions for that out... I'm embarassed to say that ours is still just hanging off the back of our batteries from it's wires! I really meant to make it nice and pretty, but... in all these years, I never have on either of the tractors.

Make sure your switch is in the "off" position and run a piece of the insulated 14 gauge automotive wire from the the positive terminal of one of your batteries to the on/off switch. Then run a piece of insulated 14 gauge automotive wire from the on/off switch to the small positive terminal (or it may be a wire -probably a RED wire) of your contactor.

Now run a piece of insulated 14 gauge automotive wire from the negative terminal of that same battery straight to the negative terminal (again, it may be wire -probably a BLACK wire) of your Contactor [remember, the Contactor runs on only 12 volts of power. If you run it on the full 48 volts of power you'll burn it out!]

Note: As with how we powered the 12volt hydraulic motor, this is the "farm" way of approaching this installation. Officially, you should have a DC converter to bring your 48 volts to 12 volts, and that should be charging a separate (fifth) 12 volt battery, and then that fifth battery is what should be powering the Contactor (and Hydraulic Pump, and any other 12 volt components you may add to your tractor... like lights.)I don't do that because I am cheap and becuase the Contactor uses so little power that I haven't observed that it is draining the one battery it is connected to more than the others. Still, I wanted to note that what I have done isn't exactly "by the book."

OKAY! You should be able to turn the switch on and drive away! If this is the first time you are running the tractor, make sure your batteries are fully charged before you really head out into the fields!

Good Luck! And please do send an email to let me know how it's working out for you and how these instructions can be improved!