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Discussion Starter #1
Hello

I have been interested in EV conversions for a while. Thought that converting a car would be too much work for me just now. Small lawnmower fits more easily in my carage and doesn`t require that much time eather. My goal is to get it finished for 2011 summer so I have whole winter to build it. I have now purchased a donor mower. It is small Stiga/Monark rear engine riding mower. I have decided that it would have separate motors for traction and mowing. I have also purchased a small forklift(pallet truck) for parts. Forklift traction motor is now installed in the lawnmower and it is working fine. The motor for mowingdeck is not so easy. I think I will use the hydraulicpump motor from the forklift but if you guys have any suggestions I am glad to hear. If you know an international source for a suitable motor I may spend some bucks for that. I live in Finland and maybe you can`t understand everything that I`m writing but you can also check some pictures in my website. https://sites.google.com/site/diysolarprojectsbyantti/lawnmowerconversion I have a building blog there. I wont write everything here in the forum but I can always discuss here about the project.
 

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Your English is very good; I would not have known you were not a native speaker if you hadn't said something. :)

The hydraulic pump motor may nto have the power to accomplish what you're looking for, given the mass of the blade. If you can find an industrial fan (not like a box fan but something with a very large blade, like a warehouse fan) I imagine that could work well.
 

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The fan motor could be very suitable but it is very difficult to find one working with DC. I am going to use 24V batterypack. That hydraulic pump motor I have is 24V 1,2kW(about 2hp) permanent magnet motor. Maybe the power is enough but the motor is not for continous duty and it might burn when used longer period. The shaft is also very difficult to use because it is so short and thin and it has no standard keyway. I also have a 2kW compound wound motor which would have much more torque in lower rpm but it is 12V model and the rotation is wrongway. I think 24V might kill it and changing the rotation is very difficult because the series and shunt windings are connected internally.
 

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I would agree with rillip3
I doubt the pump and motor combo you have will have the power or torque you need to run the mower blades. You also need to to ensure that you run the blades fast enough to cut the, aim for 65m/s tip speed. You could make new blades to solve the direction problem, blades made out of steel bar will work OK just make suree they are fully balanced. Depending on your deck size and the type/lenght of grass you intend to cut will to a large extent determine your cutting power requirements.
 

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If you have a suitable fan knocking around, try and check it out. A lot of common AC motors are single-phase, which will work fine on DC. I'm not sure if your fan will clearly list this information on it's motor, so if you have a spare you can try it out. Worse case scenario, you let the magic smoke out of a fan for a few bucks as an experiment.
 

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I'm interested in doing the same thing. I was wondering what kind of battery you were using and how long it runs the mower for.
 

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Discussion Starter #7
I'm interested in doing the same thing. I was wondering what kind of battery you were using and how long it runs the mower for.
At first I am going to use two used car batteries for testing. But maybe later 80Ah or 100Ah deepcycle. I hope to get half hour running time. I think it`s not necessary to get longer running time than needed for one time mowing. You can always recharge it when done mowing.

I checked about ten different fan motors. They were mostly 3 phase and those which were single phase didn`t work with DC. Single phase motors have a starting capasitor and are brushless. So I am still going to try the pump motor.
 

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I like you projekt !

In my garage are my Husqvarna Rider 13 waiting to be converterd.

All parts are in stock : 9hp BLDC , 25pc 90ah TS , Mini BMS , Kelly 400 a controller.

I will use the standard transmission and ony one motor.

But right now the grass is still growing.....:mad:
 

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That is interesting Peter. I hope you show us some pictures of your mower project too. Jag förstor bara liten svenska so the pics will tell me much more than the text in your site:).
 

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Wow Peter, it really looks great. Could be a bit expensive build, I think.

I have also made some progress with my project during the winter. My mower is now nearly finished and it is working ok. I still need to improve the running time a lot. I am planning to do it by changing better batterys and maybe finding a better motor for the blade. The motor from the hydraulic pump works but it is very inefficient. Pictures and more can be seen here http://sites.google.com/site/diysolarprojectsbyantti/lawnmowerconversion
 
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