Getting closer

With the single pulley reduction, I hooked up 36V and took it for a spin. WAY too fast for mowing! I changed to 24V, which gave a perfect speed. So I measured current draw at 24V to help figure out battery size. I needed 30-50A on my yard (straight, turning, slight elevation changes, etc). Too much. I wanted to keep the drive in the 20-30A range.

I thought putting the original variable pulley back in would slow it enough to run on 36V and lower current. After ordering replacement belts and tension springs (which I didnt need, I just misplaced the originals) I put the original system back in.
Advantages: 6 mechanical speeds, original design
Disadvantages: 2 belts, much more complicated system.

But at 36V it was still too fast for mowing, except for in the lowest speed setting available. The highest speed setting was like a go-cart. Fun, but not as useful! So I tried it at 24V. PERFECT speeds! Mowing in the upper speed ranges, extra slow in the lower ranges.

I figured I'd need a little less current maybe. Nope, it still draws 30-50A.

So it looks like I may have little use for the electrical 2 speed I built. I havent tried running it with the series resistor yet, but I'm happy with the speeds at full voltage.

PULLEY
I had to make myself a new pulley for the motor. The belts are 5/8" wide. I dont have the original pulley that was on the engine (it wouldnt come off). I just cast a large cylinder of aluminum and turned it down to a pulley. My motor has a very large shaft (3/4" IIRC), and I cut the pulley to be as small as physically possible while still fitting on the shaft. It seems to get fairly warm when in use. I hope it's not bad, I really dont know.

BATTERIES
So I figure It will take me an hour (probably less) to mow my yard. It takes me about an hour to do it now with my electric push mower. I assumed an average 40A draw for an hour to a 50% DOD. So I need at least an 80Ah battery, or 120 minute Reserve Capacity. I still dont know how I'm going to spin the mower blade though. I bet the drive motor has plenty of power to spin it, I just have to try building an adapter shaft to hook it up.
I'll just have to go visit a few battery places to see what is available. I dont have a lot of room on the mower to mount batteries. I think I can fit a couple of 12V RV or marine batteries behind the seat.

WELDING
I've always wanted to weld at home. I have used oxy-acetylene and MIG before. I looked into stick welding a bit and found it's not as difficult to do as I thought. In fact, the Electrack had a welding attachment that just taps into the batteries. I bought some 1/16" welding rods, goggles, and a torch. Using some old jumper cables I hooked up a pair of 12V batteries and started welding the plow ladder out of EMT conduit. WOW! I was welding at home without a >$200 machine! I was quite excited and surprised, and very happy that I can now do my own welding. when I finish my lawn tractor, I will have a semi-portable DC welder too.

TRAILER
I know, I dont even have the mower fully working and I'm already making accessories? Yup! It was fun and easy to do. I've already used it too! I picked up some 4x8" wheels on sale. I found (dumpster diving) and bought some 1/2" and 3/4" electrical conduit. I bought the axle. Also one sheet of 4x8x1/2" plywood and an 8' 2x4. I based mine on plans available online. I adjusted it slightly to suit what I had, keeping the center of gravity over the axle, but the piviot point behind the CG. I also had to raise it up a little to fit the tires I have, and I wanted it light weight. The metal frame is very light, maybe 10lbs. The box is 40"x31"x12". It seems bigger than I invisioned it. I sized it the same width as the mower, both will fit through a doorway (into my garage). I'm in the process of staining the box and designing the hold down latch. I'm thinking about adding a linear actuator to automate the dump mechanism. Maybe later.

PLOW
I built up a ladder that mounts to a couple of piviot brackets on the rear axle and protrudes under the front wheels. It attaches to the mechanism which raises/lowers the mower deck for vertical lift. Install/remove with just 3 pins. It wont provide downforce, but some weight on the end might work. Now I need to finish the front end of it and figure out some kind of blade.

METERS
I ordered some LED meters from China on ebay. I got LED so they could stand up to outdoor temperatures (cheap LCD wont). I bought 200Vdc and 100Adc 4 digit meters. I dont know where I will put them yet. I'm thinking they will go best at the base of the steering shaft.