Electric Skid Steer - Opinions Wanted

[Braddudya]

My wife and I bought our first house. I probably have a million way more important things to do but I can't help exploring building a small electric skid steer for working around the property.

Objectives for skid steer:
Haul up to 1000lbs of gravel, rocks, concrete, lumber, tools, etc
Plow driveway
Front bucket - move and spread gravel and light dirt work

Wishlist:
Fork attachment to move pallets
Lawn Sweeper attachment
Onboard inverter for mobile AC power

Initial Exploration:
I want it to be as simple a machine as possible. My first idea is to simply use 4x or 6x high torque low speed hub motors. The best I have found so far are these.

https://www.alibaba.com/x/B1cjz6?ck=pdp

If I run the 4x config I could use 2x vesc dual output controllers. Using stick controls I could have the right stick control the right two motors and left the same. From my initial reading it should be possible to implement electronic braking (assuming no free wheel) and traction control. I may need some sort of mechanical brake for parking and/or additional braking for hauling heavy loads.

Battery:
One reason this project seems doable is that I am sitting on a bunch of lifepo4 a123 cells that could be used for a "free" (money currently wasted) battery for this thing. I don't think I have enough to give it a long range but I'm sure it's enough to haul some stuff around the yard for awhile.

Questions:
1. Is it realistic that I could get a skid steer like experience using these high torque motors and electric braking from a setup like this? Can I setup the controller to actively brake (opposing magnetic force) and mostly avoid mechanical brakes while driving?

2. Do you all think this is a silly idea? I would like it to actually be able to reliably do dirt work and climb hills while hauling heavy loads. I could always buy a gasoline standing mini loader or just rent a bobcat instead. I am certainly capable of welding up a heavy frame and building the battery to support it but I'm not sure if these available hub motors are up to real work and I cannot find many cases of people putting them to work.

3. Would you recommend an alternate configuration? Maybe 2x high roque motors with chain drive to the wheels?

I guess I am asking the impossible question of does this idea make sense or am I going to end up with a silly yard toy haha.

 

[A-DamW]

I guess I am asking the impossible question of does this idea make sense or am I going to end up with a silly yard toy haha.

If I were to build from scratch, I would use opensourceecology's design for inspiration, or directly copy: LifeTrac
Check out their other cool open source machines

Personally, I would start with a used chassis that fulfilled your needs.
You could probably find a cheap used one with a bad engine, swap in emotor, controller, batteries, done.

 

[offGridDownUnder]

The first task I would do is to work out real wheel (not motor) speeds to ensure I can turn the machine safely. I expect you'll discover these speeds are rather slow at the final axle. Then consider the ramp-up from zero to the slow speed that permits a safe turn - no jerks, no sudden movements with 1000lbs. next to your body.

This is pencil and paper work and you can do this now to define the bottom end of the envelope for the capabilities you need. When you have those figures, you can check what that translates into for straight motion to consider if those speeds are enough or if you need to be able to do more for the entire envelope of desired movements.

With that, I'd have an idea of what translation there must be between whatever motor and the now-defined wheel speeds. I'd also look at torque in light of this.

You can do this on a rainy day for little cost. I'd also start getting the idea that my controls will not be mounted on the machine, but rather at the end of a cable bundle so I can stand far enough away that when it jerks and tips while it's side-hill it can't fall on me.

Having gotten this far, I'd consider if I moved 1000lb loads often enough to bother. How many of those can I split into 4 250lb loads and how often must I do this? Grin supplies a wheelbarrow motor and controls - you could put two of those on a frame with a removable barrow that could also mount a small blade for snow plowing.

How often do you need to move a loaded pallet? If it comes from off-property, I'd expect the delivery truck to manage unloading the pallet, and they can put it where you want it stored - will you need to move it many times?

 

[Braddudya]

Quick update: doing more rough calculations I have come to the end of this project. The price quickly approaches the cost of a new stand on back chinese skid loader not even considering labor hours required. It may not have the same capabilities but it's already tested and doesn't require building from scratch. I'm really not looking for stuff to do (I have plenty) so I think the existing product just makes more sense for me. I still think it would be a cool project but I don't have the time when something similar already exists for similar cost.

 

[OlderGiantFan]

Some things are best left to diesel and gas, earth moving being one.