Electric Dixon Zero-turn Mower conversion

[Hondo]

Hi guys, it's been a few years since I last posted, but I have a new project. I bought a small Dixon Zero-turn mower with the idea of converting it to electric a few months ago thinking it would be a great winter project down the road, But after the intake valve stuck and bent the push rod, I was suddenly motivated to get it done right away. So I had a 48 volt golf cart motor (3.1 HP) laying around from a previous project that I thought would work. I made an end plate with a bearing and splined and welded a shaft into the open end of the motor. It bolted up very easily and I got it running in just a couple days. The motor doesn't spin quite as fast at 48 volts as the original, so it doesn't mow quite as fast, but it works. My question to you guys is can I put on one more battery (I have room) to bump the voltage up to 60 volts without damaging the motor? I am not using a controller, just contactors on both sides of the motor. There is a slight load on the motor at all times to turn the Z-drive mechanism via a v-belt, but I am concerned I might over-rev the motor. What do you guys think? Also it would be nice if I could pop wheelies like Ben.

Hondo

[oil pan 4]

As long as you don't over heat the motor you could hit it with 90 volts, but only for a very short time.
Also that motor could be shunt wound and be roughly limited to around 2,600rpm.

The mower motors I have seen are almost always permanent stator magnet with wound armature.

[thingstodo]

Originally Posted by Hondo

My question to you guys is can I put on one more battery (I have room) to bump the voltage up to 60 volts without damaging the motor? I am not using a controller, just contactors on both sides of the motor. There is a slight load on the motor at all times to turn the Z-drive mechanism via a v-belt, but I am concerned I might over-rev the motor

I know that you can test it without harm. Wire in the extra battery with temporary cables and try it out. The human ear is pretty good at judging 'slower' and 'faster' by the pitch of the motor. 'too fast' is a bit subjective ...

If it sounds like it is not going to explode during your first test, I'd put some reflective tape on the shaft and measure the RPM with a hand-held tachometer. The golf cart motors have rated RPM on the nameplates, so you can compare. If the motor nameplate is not readable, a google search may get you your info anyway.

The hydro-static drive (is that what z-drive means?) will also have a maximum speed. That would be in the original service manual, but I'm not sure where else to look. The noise that I hear from my zero-turn mower is mostly the hydrostatic drive. I know what it SHOULD sound like, so I'd be able to tell if it was running WAY too fast. Not sure if I could tell a BIT fast though...

Sounds like you have no idea what current the motor is drawing. You may want to put a shunt resistor between the motor and the negative battery contactor. A 200 amp resistor should be fine. A shunt ammeter display or a meter that reads milli-volts across the resistor will give you approximately how much current you are drawing. The batteries will have a bit of sag, so 48V at about 50 amps would get you 2400 watts, close enough to to 3.1 HP * 746 = 2312 W. You'd only need 40 amps at 60V to get about 3.1 HP. More amps will eventually cook your motor.

[Hondo]

Thanks for the input guys. I don't have an amp meter yet, but one is on order. I decided to give it a try last night at 60 volts, and it went VERY well. About the same speed as with the ICE and the motor didn't get much warmer than at 48 volts. Mowed the whole back yard which was tall grass and pretty wet.

The Z drive is actually Dixon's mechanical/friction drive. Dixon was the first company to come out with zero turn mowers (in the 70's I think) and they used this system up into the 2000's when they switched to hydraulic. It is really a cool mechanism that uses 2 rubber "cones" and two dish shaped discs controlled by the levers to put power to the rear wheels individually.

Time will tell how this all works out, but I am very happy with it and will start making a better battery rack for the front, and covers for the batteries.

Will try wheelies later.

Hondo

[Piotrsko]

The issue with higher motor voltages will be commutation arcs AKA Zorch and toasting the rotor windings from overheat. Also overspeed unloaded.

[Hondo]

On a side note, my next project will be to electrify this 2 wheel drive motorcycle.

Hondo

https://ecomodder.com/forum/attachme...1&d=1538059733

[samwichse]

Hey, it's a Rokon!

[Hondo]

Originally Posted by samwichse

Hey, it's a Rokon!

Yes, and it surprising how few people know about them. I have so many small trees on my hunting land that it is difficult to get through there with my 4 wheeler ATV because it is so wide. I saw someone convert one of these to electric and I said "I gotta have one of those!"

Hondo

[oldtamiyaphile]

Originally Posted by Hondo

Will try wheelies later.

Reminds me of:

https://www.youtube.com/watch?v=MVdn9r-zLMQ