OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Ride On Mowers Questions on Greenfield Ride On Mower Frames Electric conversion of a Greenfield ride on

In order to give something back as I solve all sorts of problems on the web I would like to share my electric conversion of a Greenfield tractor 8.

I am told that this mower is about 25 years old, I was given 2 of them years ago and always wanted to convert 2 into 1 electric one after I saw an electric conversion in Seattle. Robert Bonnell did the conversion that inspired me, he gave me the �next time I would� advice that helped me size the batteries etc. Thanks for the tips and inspiration Robert!

EV Drives sell a DC motor that is sized to replace ride on mower motors, 3600rpm @ 48v, even the motors drive shaft fit the drive pulley so it was very easy to replace the petrol motor.

My partner is a solar installer so she did the electrics and sized the batteries, 85 amp hour x 4 batteries = 48v, they are 30kg each.. I have only just started using it so don't have lots of knowledge on how much area I can mow per charge but it has been designed to last for 45 minuets. It draws 50amp when on, 70amp when driving and 120amp when driving up hill and mowing. It goes very fast and cuts 50cm grass no problem.

The motor is very exposed to dust and grass so I added a fan and filter, the big white protrusion on the bonnet. By blowing filtered air into the motor it stops grass and dirt, the fan also helps cool the motor which is only a good thing even through it is designed to run at up to 80C.

We are avid gardeners so collecting mulch is a must, I can fill the back of a ute with cut grass from one charge! That is full and overflowing. I had to make a bracket to hold the catcher to the mower as they are no longer available, a new catcher fit just fine.

Much of the mower has been re built, fixed along the way. I found many of the original welds to have very poor penetration so with its age and my working on it a few have broken and needed re welding.

The project cost a bit, $1000 for the motor and electrics and $1000 for the batteries, then restoring it, battery holders etc.

The reason I love electric vehicles is the quiet operation, the torque you get, fast and never stalls! I charge it from solar panels as our house is off grid, no oil changes or stinking petrol and it starts with the flick of a switch!

The main question in my mind is whether you can reduce the motor speed below 3,600 rpm? With a petrol engine on a Greenfield, you have an engine speed control, and the art of using the machine successfully requires that you use the lowest engine speed you can, so that the amount of clutch slip is minimised. If the petrol engine is allowed to run at its maximum speed of about 3,200 rpm while manoeuvering or mowing at less than maximum speed, the forward clutch becomes glazed. Then it is likely to squeal, slip erratically, and be generally annoying.

In my design it has a set motor speed. If I was starting from scratch I could select a mower where the accelerator is the speed control like in a car not a clutch slipping. A variable speed control would essentially be the accelerator.

Thanks Paul, that answers my question. I suppose you will be able to observe what happens to your clutches over a period, and consider adding a speed control if it turns out to be necessary. Alternatively you could reduce your fixed motor speed, or change the final drive sprocket ratio. However because you have 4 batteries, a simple contactor-controlled selectable motor voltage system seems the easiest to implement. The down-side is that you would then have to charge the 4 batteries individually, requiring 4 regulated, high current 12 Volt battery chargers.

The Greenfield clutch system seems to work very well, provided you have a governed petrol engine with variable speed. The Briggs petrol engine has a minimum speed of 1,750 rpm and a maximum of about 3,200. Of course you can't get much torque out of the engine at idle, but from about 2,000 rpm upward it will pull quite vigorously. My current guess is that you are going to have to make a change of some kind in your electrical design to achieve something similar, but time will tell.

Hi Ravin, Hope you are still around the forum to accept an accolade. Awesome conversion, and considering you did this 9 years ago I hope it is still all going well. Many thanks for sharing.

Kindest regards
Paul