My modular hybrid farm toy idea.

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Fireside
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My modular hybrid farm toy idea.

Post by Fireside » Sat, 26 Nov 2016, 14:22

Hi all, new member here. Not entirely sure which section this question belongs in so I though't I'd just say G'day and throw the idea out here in the lounge.    I'll try not to get any on the carpet.

I'm based in Qld down on the border East of Stanthorpe. But I come up to Toowoomba to access the internet and various other services. I have a background in mechanical engineering, and I'm an avid tinkerer with a reasonably well sorted workshop.

I've had this idea for a small skid steer vehicle to be used in the bush as a general purpose mini tractor/tug, with a flail mower attached to the front for slashing and mulching pest weeds like blackberry throughout a forested setting.

Originally I was just going to take a small ICE FWD engine and go with a mechanical solution. But recently while lugging a 5.5Kw generator around, it crossed my mind that I should consider some sort of hybrid electric design.   I've done a lot of reading, but the numbers don't mean much without the benefit of experience, when trying to decide what sort of motors would be "enough".   

So I joined up to ask some questions and get peoples thoughts.   The vehicle doesn't need to be fast. If it could go faster than I can jog between work sites, that would be great. Ideally it would be able to tow a small utility trailer.. Perhaps even drag a small (6-8") log 100m or so.

I would like to use an Over The Tire rubber track system. So I'll need two motors and controllers. And I like the idea of being able to slot the genny {frame and all} into a recess at the back of the chassis. I'm not particularly worried about weight. And will design the size to suit.

An optional 3rd or even 4th motor to drive the flail mower and perhaps a small hydraulic pump. (powersteering pump)ish... Would be great.

And beyond that I have no idea what would suit best.. DC, AC with or without supporting batteries etc. I welcome any and all thoughts on the idea. Image
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jonescg
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My modular hybrid farm toy idea.

Post by jonescg » Sat, 26 Nov 2016, 18:22

So Liston then? I come from Warwick so the whole area is my old stompen ground. Sounds like a really neat project. I've always wanted to build an electric tractor capable of light duties, or the occasional heavy duty job. AC is a superior drive in every way, but DC is cheaper. DC motors don't like moving at high torque demands and very low RPM, so if you were to use a big DC motor you would want to gear it quite generously which is about right for a slow jog.

Hydraulics are rather lossy, but they are more forgiving in sticky situations (like digging a post-hole and hitting a rock). Parker make some small but torquey servo-style motors with bevel gearboxes which could run the hydraulics, or even do the digging directly.

Batteries will set the overall scope of the project, but shouldn't be decided upon until the rest of it is sorted. For an application like this you can get LiFePO4 cells for about $600 per kWh.

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Fireside
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My modular hybrid farm toy idea.

Post by Fireside » Sun, 27 Nov 2016, 02:35

Hi, yeah just down the road from Liston. The hydraulic option I have in mind is probably just a single piston to raise or lower the cutting height of the flail mower. I guess I could probably achieve that mechanically with an electric motor as well. Even a small pneumatic solution would probably be more suited as I think about it.

Am I being too simplistic thinking a pair of 240v stationary motors with speed controllers running directly off the genny might do the trick?

Something like this.. http://www.ebay.com.au/itm/2-2kw-3HP-28 ... 5731.m3795
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Richo
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My modular hybrid farm toy idea.

Post by Richo » Mon, 28 Nov 2016, 20:42

Fireside wrote:
Am I being too simplistic thinking a pair of 240v stationary motors with speed controllers running directly off the genny might do the trick?
Yes - too simplistic...
ebay motor
That's a single phase cap run motor - not really suitable for speed control.

Sort of on the right track - pardon the pun Image

Controller ebay 272338747720 $150
Motor ebay 171756190172 (3-phase 2.2kW 4-pole) $211+shipping

Although I haven't looked at them closely for suitability they'd be better than a cap motor.

Still I'd be skeptical if that was enough for traction.
Think of a couple of weak 50cc scooters..

The Motenergy motor might be more suited to traction.
There are others available AC and DC in this range.

Guess it depends on how much you'd want to spend on all the electrical side of things.
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Richo
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My modular hybrid farm toy idea.

Post by Richo » Mon, 28 Nov 2016, 20:46

If you add a small battery pack you can run the two motoenergy motors 30kW peak.
Then have a 2-5kW Battery charger running off the genny.
Could give you ~10km range in ev mode.
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Richo
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My modular hybrid farm toy idea.

Post by Richo » Tue, 29 Nov 2016, 20:27

Have a look at this:

It's 145kg, 40kph, 10kW - ONLY $9,000...
If only it had a seat I'd be there Image

http://www.ozimall.com.au/dtv-shredder- ... in-vehicle


Image
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