Electric Conversion

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  #1  
Old 12-06-10, 09:22 PM
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Electric Conversion

I have a Wheel Horse 265-H (hydrostatic drive), and am interested in replacing the vertical gas engine with an electric motor that will put out the equivalent of 20 to 25 HP.

It would turn the vertical shaft continuously, and as the drive pedal tightens the belt the tractor transmission engages, forward and reverse as it does with the gas engine.

Does anyone have experience, advice, suggestions, resources for doing this? Are there books, plans, websites where I can learn what's needed and how to put it together?

Thanks,

Antifa
 
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  #2  
Old 12-07-10, 12:24 AM
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A D/C motor? I doubt there are plans out there for putting a 25 hp electric motor on a mower. Can I ask why you want to?
 
  #3  
Old 12-07-10, 03:18 AM
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Well . . .

My property is a 15 acre woodlot, with two acres cleared for raised bed gardens. And it is all on a slope -- I swear the only level ground on the whole place is the kitchen floor.

If the guy who originally built this house had put it at the bottom of the property instead of the top, I could just roll firewood down to the house (and replace the occasional window when I miss).

But he didn't. So I haul firewood uphill a lot, and I haul trailers full of manure uphill to the garden as well. I never mow with this tractor, just haul stuff uphill with it.

The tractor originally came with a 15HP Kohler engine, which lasted 7 years before breaking its rocker arm. I asked the repair shop for a 20 or 25 HP, but they replaced it with a 13HP Kohler, saying they couldn't find anything bigger.

Which means this smaller engine can only haul smaller loads, and is still likely to die itself in a year or two. There is no reason to think I will be able to find a large Kohler engine for it at that time, meaning a new tractor must be bought.

I'd rather spend that money when the time comes on converting to a fully electric tractor that I can charge via solar or house current. It will be quieter, which will allow me to work near the house early mornings in the summertime without waking up everyone.

No, I can't just buy a golf cart because it would be too wide. The thing I value most about this tractor is its 36" width, which I built the two-acre garden around, all raised beds and all 48" apart to allow me to get in between them with the tractor/trailer and still have room to stand.

I just prefer electric going forward. Even if I could find a 25HP Kohler vertical engine, I would prefer electric.
 
  #4  
Old 12-09-10, 09:44 AM
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A 25 HP electric motor is HEAVY, and will need a LOT of batteries to run. I'd suggest a 15 HP electric motor as it will generate enough torque to do what you want. I realize you are looking for a DC motor, but to give you an idea, a 25 HP AC motor will weigh in the neighborhood of 360 pounds and requires 78 amps @ 240 volts at full load. Yes there are sites around about folks that do this sort of thing. Try a Google search for "electric tractor conversion"
 
  #5  
Old 12-09-10, 09:55 AM
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Just did a little reading and a 5 HP electric motor will likely do all you need to do. Much better torque curve with electric than with gas.
 
  #6  
Old 12-09-10, 10:05 AM
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Thanks . . .

It will definitely have to be a DC motor, and I figure 24 or 36 volt from linked deep cell batteries.

There are a few useful websites out there.

It has become clear that direct drive to each wheel is more efficient, and has the advantage of eliminating the hydrostatic transmission, so I am looking at that as well. I may end up getting a small ATV frame and tinkering with that instead.
 
  #7  
Old 12-09-10, 10:47 AM
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From the few minutes I spent reading, seems like keeping the hydro would be cheaper and allow the motor to run at a constant full speed, developing full power while using the hydro to vary your ground speed. I'm guessing that coupling the motor to the hydro would be fairly simple vs. coming up with direct drive to each rear wheel. Yep, I know it will be less efficient, but that's your call. I have no idea what kind of time or budget you have to invest in this. Sounds like an interesting project.
 
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Old 12-09-10, 12:50 PM
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I would look at after market golf cart components. There are many high performance DC motors and speed controllers available. The motors probably are not right for your application since they lack a bearing on the output end, but the high amperage speed controllers could be useful.
 
  #9  
Old 12-10-10, 07:59 AM
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Questions, looking for information and advise

Hello everybody,

I have an interesting problem, but need more information to solve it. I have an input of 72 volt and 230 amp DC. I want to invert this to AC. Currently I have a 12 volt inverter.

How can I (cost effectively) convert 72 volt into 12 volt?

What will happen to the amps (will they go, up down or stay the same)?
 
  #10  
Old 12-10-10, 03:02 PM
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I agree about coupling the motor to the hydro being the simplest and most cost effective way of doing this. You won't need a very big motor, as mentioned. Gas engines are rated at their peak hp, while electric motors are rated at their continuous hp output. Electric motor peak output can be 8-10 times their hp rating. Electric motors also generally have far more torque than gas motors, so a 5hp electric motor may be more than you'll need. A 3 hp motor might even be more than needed. Horsepower by itself means nothing until you factor in rpm. You'll want to be able to run the hydro pump shaft at the same speed the gas engine did, so if it is direct drive, you'll want an electric motor that can deliver around 3200-3600 rpm. If you can't, then you either have to settle for less speed, or gear it up with a pulley system. If you find a 3 hp motor that is rated at 3500 rpm, it will not have the torque of a 3 hp motor rated at 1750 rpm. I'm no expert on the subject, but those are just some of my thoughts about attempting the conversion.
 
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Old 12-10-10, 04:43 PM
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Originally Posted by Duec2 View Post
How can I (cost effectively) convert 72 volt into 12 volt?
Assuming you have 6 - 12 volt cells/batteries you would just rewire them in parallel rather then in series. Connect all the negatives together, and all the positives together.

Originally Posted by Duec2 View Post
What will happen to the amps (will they go, up down or stay the same)?
As voltage goes down, amps will go up.
 
  #12  
Old 12-13-10, 04:45 AM
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You say you want to convert 72 volt DC to AC, and you say you already have a 12 volt inverter. Why do you want to convert to AC? Is this to run an AC motor to power your tractor or do you just want a 120 volt outlet to power had tools?
 
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