# [EVDL] Best lawn tractor for conversion?



## EVDL List (Jul 27, 2007)

I want to convert a riding mower or lawn /garden tractor this winter.? Who has opinions on the most appropriate model?? 
I've got a very beefy motor thanks to Jim Husted and the 2007 Nedra Nationals Raffle ;-p
However,?I?am torn between the light weight and simplicity of a classic Snapper rear engine rider versus a heavier lawn tractor (I've got enough bb600 nicads left to make a small high-power 36V 34 ah pack).? A garden tractor with more attachment possibilities could be nice, but is more than I really need.? 
Plus, I sent an inquiry to the National Lawn Mower Racing Association, as their rules currently require gasoline.? With that 7.5" Husted Special, I'd sure like to at least give a demonstration run at the local NLMRA races!!!
Anything out there use a shaft drive instead of v-belts?? Hydrostatics strike me as less efficient, and?seem to be?quite pricey even in the salvage market...
Also, this mower will need to mow, not just race.? I've also got a couple of 24V cordless push mowers that I've contemplated cannibalizing to power the mowing deck, eliminating one belt and allowing more independent adjustment of blade speed vs ground speed.? 
Other ideas?
Thanks, 
Jay Donnaway
www.karmanneclectric.blogspot.com
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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

Hi Jay,

Yeah, electric yard tractor conversions are fun, and
useful. I did one about 15 years ago. Have used it a
lot ever since. I don't mow with it. Mostly tow a
trailer, yard waste, firewood, rocks, etc. Batteries
give me good range doing this. When I pull the lawn
sweeper, it loads it up to 30 to 50 amps, and I only
get about 15 minutes. Mowing decks suck a lot of
amps, so you don't get much range, unless you use
large batteries.

I bought a used Sears tractor. I think it was about
10 or 12 hp gas. It was well used. No engine. No
deck. Good seat and tires. 3 speed axle with
reverse. $25. Mounted an old 6.6 inch floor sweeper
motor vertically under the dash. Belt drive to
original transaxle pulley. Played with pulley dia on
motor and belt length. Got it nice where 2nd is
normal, 3rd on pavement to about 25 mph. First can
pop wheelies. Curtis 36/48 v, 225 amp controller. 
Started with 4 lawn tractor starting batteries at
about $17 each. After a few years, got 4 Hawkers,
about 30 amp-hrs. Those did great. Lasted 8 or 9
years. Now I have some UPS batteries about same size.
Don't like those much, after the Hawkers, but they
were less $.

I like the belt drive. Pretty simple to do. And
cheap. Easy to change ratios. I did eliminate the
tensioner/clutch. Still has the friction brake. 
Brake pedal pushes a microswitch to turn the
controller off. I use a throttle cable to the PB-6. 
So the friction brake would not stop the vehicle
unless the motor was turned off. 

I finally put new rear tires on a few years back. Got
tired getting stuck in the snow. Got those ones with
big deep lugs. The old electric tractor looks like
crap, but just keeps running and running. I just
replaced the line contactor a couple weeks ago. It
had been acting up for a few years. It used to stick
on. I think it was on for 6 or 8 months once. I just
kept the batteries charged. I could get it to open up
by striking it with a steel tool. But it started not
to close. So replace it and installed a precharge
circuit. Hopefully that will prevent contact welding
and last longer than 15 years.

Have fun.

Jeff M





> --- [email protected] wrote:
> 
> > I want to convert a riding mower or lawn /garden
> > tractor this winter.? Who has opinions on the most
> ...


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## EVDL List (Jul 27, 2007)

Hey, Jeff: I had been thinking of converting using a shunt or PM motor so you always got a consistent RPM. Have you found it has been easy to use a series motor and controller?

Do you just set the throttle using the lever and then leave it alone like you would with a mower set up to run on gas? Have you had any problems with overspeed?

Thanks!



David Brandt


----- Original Message ----
From: Jeff Major <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Friday, September 28, 2007 12:10:28 PM
Subject: Re: [EVDL] Best lawn tractor for conversion?


Hi Jay,

Yeah, electric yard tractor conversions are fun, and
useful. I did one about 15 years ago. Have used it a
lot ever since. I don't mow with it. Mostly tow a
trailer, yard waste, firewood, rocks, etc. Batteries
give me good range doing this. When I pull the lawn
sweeper, it loads it up to 30 to 50 amps, and I only
get about 15 minutes. Mowing decks suck a lot of
amps, so you don't get much range, unless you use
large batteries.

I bought a used Sears tractor. I think it was about
10 or 12 hp gas. It was well used. No engine. No
deck. Good seat and tires. 3 speed axle with
reverse. $25. Mounted an old 6.6 inch floor sweeper
motor vertically under the dash. Belt drive to
original transaxle pulley. Played with pulley dia on
motor and belt length. Got it nice where 2nd is
normal, 3rd on pavement to about 25 mph. First can
pop wheelies. Curtis 36/48 v, 225 amp controller. 
Started with 4 lawn tractor starting batteries at
about $17 each. After a few years, got 4 Hawkers,
about 30 amp-hrs. Those did great. Lasted 8 or 9
years. Now I have some UPS batteries about same size.
Don't like those much, after the Hawkers, but they
were less $.

I like the belt drive. Pretty simple to do. And
cheap. Easy to change ratios. I did eliminate the
tensioner/clutch. Still has the friction brake. 
Brake pedal pushes a microswitch to turn the
controller off. I use a throttle cable to the PB-6. 
So the friction brake would not stop the vehicle
unless the motor was turned off. 

I finally put new rear tires on a few years back. Got
tired getting stuck in the snow. Got those ones with
big deep lugs. The old electric tractor looks like
crap, but just keeps running and running. I just
replaced the line contactor a couple weeks ago. It
had been acting up for a few years. It used to stick
on. I think it was on for 6 or 8 months once. I just
kept the batteries charged. I could get it to open up
by striking it with a steel tool. But it started not
to close. So replace it and installed a precharge
circuit. Hopefully that will prevent contact welding
and last longer than 15 years.

Have fun.

Jeff M





> --- [email protected] wrote:
> 
> > I want to convert a riding mower or lawn /garden
> > tractor this winter.? Who has opinions on the most
> ...


----------



## EVDL List (Jul 27, 2007)

Hi David,

Actually it is a compound wound motor. It was rated
for 24 volts. But what the heck. Seems to work just
fine at 48 volts and a Curtis intended for series
motors. I never checked RPM, but does not seem to be
a problem, even in neutral and full throttle. If run
hard, 40 to 50 amps, you only go about 15 minutes. 
More typical stop and go with the trailer, maybe 20
amps for an hour or two. Motor does get hot to touch,
but never any smoke (knock on wood). Controller has
no problem (knock on wood, again).

I first tried a 5.5 inch PM motor. I did not think it
pulled well. Didn't use it long at all. I did
another one, an Elec Trak rebuild for a guy using a
bigger PM motor and 400 amp Curtis at 36 volts and it
pulls great. Have seen it pull a train of 5 wagons
total of about 3 tons. Even up slight grades. He
went to a chain drive. It is geared lower than mine.

Yeah, on mine I just used the original speed lever. 
Shortened up cable so it goes to PB-6 instead of carb.

No over speed problems. But you probably thought I
had a series motor. If you do use a series motor, you
will have to deal with that. On a go cart we did, we
put on a speed sensor and circuit to turn off the
Curtis at a set speed, 5000 RPM, I think. That seemed
to work well. Just wanted to protect the motor in
case the chain broke.

When it comes to these small tractors, you can use
just about any type of motor. They are a great way to
get your feet wet with EVs for not much $. If you are
going for a high end job, I suggest a SepEx motor and
control. I use SepEx on some IUVs, and next to AC
induction motors and inverter drives, I think they are
the best way to go. SepEx is about same $ as series
motor and control combos and gives you regen and
programmable top speed and lots of other features.

Jeff M




> --- David Brandt <[email protected]> wrote:
> 
> > Hey, Jeff: I had been thinking of converting using
> > a shunt or PM motor so you always got a consistent
> ...


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## EVDL List (Jul 27, 2007)

I ended up with a McCullough electric push mower. These are Chinese made and
what you might expect. Still, I replaced the batteries with a couple
Hawkers. It has only about 60% of the rated power, but the new batts last as
long as the larger originals.

It's about right to mow my small yard, if I don't let it over grow. The good
part is, about the time I'm getting bored, the batts are going dead, so it
gives me an excuse to knock off.

I do miss the self-propelled, but not the gas and maintenance.

----- Original Message ----- 
From: "David Brandt" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, September 28, 2007 1:10 PM
Subject: Re: [EVDL] Best lawn tractor for conversion?


> Hey, Jeff: I had been thinking of converting using a shunt or PM motor so
you always got a consistent RPM. Have you found it has been easy to use a
series motor and controller?
>
> Do you just set the throttle using the lever and then leave it alone like
you would with a mower set up to run on gas? Have you had any problems with
overspeed?
>
> Thanks!
>
>
>
> David Brandt
>
>
> ----- Original Message ----
> From: Jeff Major <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Friday, September 28, 2007 12:10:28 PM
> Subject: Re: [EVDL] Best lawn tractor for conversion?
>
>
> Hi Jay,
>
> Yeah, electric yard tractor conversions are fun, and
> useful. I did one about 15 years ago. Have used it a
> lot ever since. I don't mow with it. Mostly tow a
> trailer, yard waste, firewood, rocks, etc. Batteries
> give me good range doing this. When I pull the lawn
> sweeper, it loads it up to 30 to 50 amps, and I only
> get about 15 minutes. Mowing decks suck a lot of
> amps, so you don't get much range, unless you use
> large batteries.
>
> I bought a used Sears tractor. I think it was about
> 10 or 12 hp gas. It was well used. No engine. No
> deck. Good seat and tires. 3 speed axle with
> reverse. $25. Mounted an old 6.6 inch floor sweeper
> motor vertically under the dash. Belt drive to
> original transaxle pulley. Played with pulley dia on
> motor and belt length. Got it nice where 2nd is
> normal, 3rd on pavement to about 25 mph. First can
> pop wheelies. Curtis 36/48 v, 225 amp controller.
> Started with 4 lawn tractor starting batteries at
> about $17 each. After a few years, got 4 Hawkers,
> about 30 amp-hrs. Those did great. Lasted 8 or 9
> years. Now I have some UPS batteries about same size.
> Don't like those much, after the Hawkers, but they
> were less $.
>
> I like the belt drive. Pretty simple to do. And
> cheap. Easy to change ratios. I did eliminate the
> tensioner/clutch. Still has the friction brake.
> Brake pedal pushes a microswitch to turn the
> controller off. I use a throttle cable to the PB-6.
> So the friction brake would not stop the vehicle
> unless the motor was turned off.
>
> I finally put new rear tires on a few years back. Got
> tired getting stuck in the snow. Got those ones with
> big deep lugs. The old electric tractor looks like
> crap, but just keeps running and running. I just
> replaced the line contactor a couple weeks ago. It
> had been acting up for a few years. It used to stick
> on. I think it was on for 6 or 8 months once. I just
> kept the batteries charged. I could get it to open up
> by striking it with a steel tool. But it started not
> to close. So replace it and installed a precharge
> circuit. Hopefully that will prevent contact welding
> and last longer than 15 years.
>
> Have fun.
>
> Jeff M
>
>
>


> > --- [email protected] wrote:
> >
> > > I want to convert a riding mower or lawn /garden
> > > tractor this winter.? Who has opinions on the most
> ...


----------



## EVDL List (Jul 27, 2007)

> David Brandt wrote:
> > I had been thinking of converting using a shunt or PM motor so you
> > always got a consistent RPM. Have you found it has been easy to use
> > a series motor and controller?
> ...


----------



## EVDL List (Jul 27, 2007)

> On 2 Oct 2007 at 7:55, Lee Hart wrote:
> 
> > The GE Electrak electric garden tractors used PM motors for just this
> > reason.
> ...


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## EVDL List (Jul 27, 2007)

Just to be a little more clear....

GE used only PM motors on all of the mower blades. The mower motors were connected directly to pack voltage through a contactor. This resulted in a somewhat stable and predictable blade speed.

They used several different sizes of PM and/or compound wound motors for the drive system in a variable speed configuration. They were constantly experimenting with the drive speed circuitry. There are almost as many different speed regulation schemes as there are Elec-Trak serial numbers ;-) 

But, all of the tractors used the same mower motor configuration. Although there are 2 different types of mower motors, they are both 36v PM motors with the same rpm/volt specs. I believe this is the part of the tractor Lee was referring too...even though the speed of the tractor may have changed because of either throttle or terrain change, the mower blade speed remained constant.

--
Stay Charged!
Hump
I-5, Blossvale NY
> 
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of David Roden
> Sent: Tuesday, October 02, 2007 11:58 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Best lawn tractor for conversion?
> 


> > On 2 Oct 2007 at 7:55, Lee Hart wrote:
> >
> >> The GE Electrak electric garden tractors used PM motors for just this
> >> reason.
> ...


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## EVDL List (Jul 27, 2007)

I have an old 1974 (maybe) cub cadet, it had an 8-horse on it. the engine is
no good and i was wanting to convert it to electric. It's a shaft drive
with the 3 foward and 1 rev. transmission. probably like to use it to pull
sweeper, wagon, etc. has any one seen one of these converted?





> dave cover-2 wrote:
> >
> > Jay
> >
> ...


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