Electric Riding Lawn Mower

67795 Views 74 Replies 26 Participants Last post by major, Mar 30, 2011

Alex Everett

Discussion Starter · May 13, 2008

I know it has four wheels but...
Starting out small here on a automobile conversion later in the year. My practice vehicle is a Riding Mower with blown engine.

I have ordered the motor (48 volt golf cart motor) on e-bay for $125.00 I have allready stripped the mower and have installed the battery racks and the batteries. Should have the wiring done this weekend. The question is....
do I really need a controller with this? I figure since the motor will be run full throttle at all times because the blades run off one belt and the selectable speed trans off the other.....

Any thoughts, Ideas, input......
I have a 48 volt on/off switch so I see no need in a controller.

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major

· #2 · May 13, 2008

Alex Everett said:
<snip>
Any thoughts, Ideas, input......
I have a 48 volt on/off switch so I see no need in a controller.

Hey Alex,

I say you should use a controller. First, an "on/off" switch? You need a contactor. You switch 48 volts of battery across that motor and you'll draw hundreds of amps. That will fry a switch. Also, across the line starting like that will pull wheelies and break things. Motor controllers have a current limit and ramp-up features which are there for a reason.

Next, is that golf car motor series or SepEx? If it is a series motor and you run without a controller, try to shift on the fly, when you disengage the motor it will self destruct.

Next, does the motor have a drive end bearing? Most golf car motors pilot on the axle bearing.

Have fun with it, but be careful.

major

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Alex Everett

Discussion Starter · #3 · May 13, 2008

major said:
Hey Alex,

First, an "on/off" switch? You need a contactor. You switch 48 volts of battery across that motor and you'll draw hundreds of amps. That will fry a switch. Also, across the line starting like that will pull wheelies and break things. Motor controllers have a current limit and ramp-up features which are there for a reason.

Next, is that golf car motor series or SepEx? If it is a series motor and you run without a controller, try to shift on the fly, when you disengage the motor it will self destruct.

Next, does the motor have a drive end bearing? Most golf car motors pilot on the axle bearing.

Have fun with it, but be careful.

major

I should have been more specific, I have switch run to 48 volt snap contactor

belts for blades and tranny have pedal/arm release features that will release tension allowing motor to spin and that will slowly engage/disengage drive and blade components preventing wheelie. I.C.E. was 5000 r.p.m. Electric is 4000. R.P.M. and it is a series wound.

I am building mounting plate, adapter shaft with bearing for support of motor end.

I am thinking about an amperage limiter of some sort without purchase of a $300. controller

JohninCR

· #4 · May 14, 2008

CloudElectric has Kelly controllers that will work for you for under $200. I picked up a 200A/100A 24-36V Kelly for $99 on sale a couple of months ago. I also picked up a brand new 350A 36-48V Curtis controller for $122 on Ebay in April.

I've got a 4hp powerpack motor that turns 17k rpms. I've spun it using a controller, but I can't imagine running it with a direct connection. Even if you can force yours to work without a controller, you'll want one eventually, so for personal safety as well as the safety of your motor, batteries and vehicle you might as well bite the bullet now.

Take care,

John

major

· #5 · May 14, 2008

Alex Everett said:
belts for blades and tranny have pedal/arm release features that will release tension allowing motor to spin and that will slowly engage/disengage drive and blade components preventing wheelie. I.C.E. was 5000 r.p.m. Electric is 4000. R.P.M. and it is a series wound.

I am thinking about an amperage limiter of some sort without purchase of a $300. controller

Hi Alex,

That's the problem. You cannot run the series motor at full voltage unloaded and then engage the load. The motor will overspeed and disassemble.

And what is an "amperage limiter"? A resistor?

Regards,

major

Mastiff

· #6 · May 14, 2008

belts for blades and tranny have pedal/arm release features that will release tension allowing motor to spin and that will slowly engage/disengage drive and blade components preventing wheelie. I.C.E. was 5000 r.p.m. Electric is 4000. R.P.M. and it is a series wound.

You can NEVER, NEVER remove the load from a Series wound Electric motor.

If your running the Series wound motor and you let the load off of the motor it will spin up to 10,000+RPM and literally Arc and explode.
This will happen even with a controller.

You simply can not run a Series wound motor without a load on it.

I would look on Ebay for a cheap Altrax 48volt golf-cart controller, just to be safe and take better care of the batteries and motor.

Alex Everett

Discussion Starter · #7 · May 14, 2008

major said:
Hi Alex,
And what is an "amperage limiter"? A resistor?

Regards,

major

I was thinking a resistor of some sort or a voltage regulator of some kind but now that others have chimed in on the "DO NOT DO THIS" bandwagon, I believe I'll go with a controller. I was just looking to save a greenback or two.

Us old folks sometimes get brain farts that lead us off to places we don't want to go......

EL Escort

· #8 · May 14, 2008

Alex Everett

Starting out small here on a automobile conversion later in the year. My practice vehicle is a Riding Mower with blown engine.

I have ordered the motor (48 volt golf cart motor) on e-bay for $125.00 I have allready stripped the mower and have installed the battery racks and the batteries. Should have the wiring done this weekend

I'm just a few days behind you on the mower. I have the Club Car 48 volt motor. A couple of battery cores for the fit and need to follow up on 2 junk golf carts which hopefully one might have a Curtis controller on it. I'll post pics on my thread soon.

Alex Everett

Discussion Starter · #9 · May 23, 2008

Here are some pics of what I have up to now. No wiring in yet but hopefully this weekend I'll have it running

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Alex Everett

Discussion Starter · #10 · May 23, 2008

Forgot to mention, The electric motor fits the opening that was made for the ICE and it is a perfec fit. Drill the holes, mount the plate with bearing on the bottom then add pully for belts.

talonts

· #11 · May 23, 2008

Alex Everett said:
Forgot to mention, The electric motor fits the opening that was made for the ICE and it is a perfec fit. Drill the holes, mount the plate with bearing on the bottom then add pully for belts.

The pulleys are my sticking point so far. I have a 24V motor, AXE controller, contactors, etc. Everything but the large cable and batteries (waiting on that until everything else is fit to the mower, so I know what batteries will fit).

The motor I have has a stepped output shaft, 7/8" closest to the motor, just over 3/4 at the end. I finally found a pulley setup on Ebay that takes a keyed 7/8" shaft, and received it, but mounting it is the problem. I'm going to have to cut the end off the motor shaft (circlip slot near the tip), then drill and tap the shaft for a bolt.

I'm trying to figure out the best way to do that, as I do NOT want to have to disassemble the motor to tap it. I might try running the motor with a 12V battery, and using a cordless drill at low speed to center the hole (if I drill before cutting off the tip, I can use the centering divot to help). The other choice is to finally unbox my drillpress, but it's a small one, so might not have enough throat to handle the motor length. I need to figure out the smallest diameter bolt that I can use, that might be tricky.

After that, I'll have to fit a washer into the pulley shaft and weld it into place, as the keyed insert in the pulley setup just ends about 2" into the shaft, with no shoulder for a bolt.

This stupid pulley mod looks to be the most involved work of the entire conversion!

In your case, you might have it "easy" - since you have to add a shaft anyways, you can mod the shaft before installing it to the motor, and make it fit whatever pulley shaft you have (in my case, the mower used a 1" output shaft, so the pulleys that came on it would not work with my motor).

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Alex Everett

Discussion Starter · #12 · May 23, 2008

second opinion...
If you have a shaft that will fit in the end of the motor and the end of the pully, try to cut the pully end to the proper length(if needed), insert shaft into pully and motor, drill transversely through shaft at each end and drive in shear pins. Trying to drill a centered hole into the shaft end of the motor will be very difficuly to do. depth is too far to see acurately and hardened metal is the most difficult to start a drill hole and keep centered. In addition, any shavings from the drilling that may fall into the motor wouild be devastating. I have an industrial drill press (6 foot tall) and I would be afraid to try drilling that way

talonts

· #13 · May 24, 2008

Alex Everett said:
second opinion...
If you have a shaft that will fit in the end of the motor and the end of the pully, try to cut the pully end to the proper length(if needed), insert shaft into pully and motor, drill transversely through shaft at each end and drive in shear pins. Trying to drill a centered hole into the shaft end of the motor will be very difficuly to do. depth is too far to see acurately and hardened metal is the most difficult to start a drill hole and keep centered. In addition, any shavings from the drilling that may fall into the motor wouild be devastating. I have an industrial drill press (6 foot tall) and I would be afraid to try drilling that way

Thanks for the input! I was trying to figure out a better way. By shear pin, I assume you mean a rollpin, the spring steel rolled pins? Or do you mean solid (what I would consider a driftpin).

That might work, and if not, I can always consider tapping the rollpin hole, and threadlocking some hardened screws into it.

NOTE - my motor does not have a removable shaft. Here are pics of what I got on Ebay:

I'm sure I can unbolt the endplate and find a splined center shaft like most Crown forklift motors, but this one already had the endplate and shaft, so I went with it. The gear was circlipped on, so it's out of the way now.

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Alex Everett

Discussion Starter · #14 · May 25, 2008

Yes by all means keep the end plate with the bearing assembly and convert your pully to go on it.

Update ----- First un-controlled test today (no controller yet) all went as planned. Did a 24 volt set up for test but had low charge on batteries. IT MOVED AND BLADES TURNED. YEEEEEEEEEE HAW Cant wait for remaining components to arrivwe so I can get some green cutting done.

Alex Everett

Discussion Starter · #15 · May 25, 2008

Sorry, I was so happy that my mower worked, I forgot to answer your question. Yes when I say Shear pin I mean roll pin as it is hollow and stands a better chance of shearing upon impact with a solid object that you may run over. A solid pin may or may not shear as easilly and could result in motor damage with unwanted impact of blade (depending upon tension of belt of course). I am having trouble determining from the photo if your output shaft is hardened steel (the gear obviously is). It does not look like it but I have been fooled before. If it is you may have to get a serious bit (carbon tipped titanium) but they are very expensive

. Get only the one you need and not the entire $500.00 set or simply take it to a machine shop that can do it for you. They can also supply the corrrect shear pin.

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major

· #16 · May 25, 2008

EL Escort said:
Alex Everett

I'm just a few days behind you on the mower. I have the Club Car 48 volt motor. A couple of battery cores for the fit and need to follow up on 2 junk golf carts which hopefully one might have a Curtis controller on it. I'll post pics on my thread soon.

Hey Alex, EL and others,

I thought I had better mention something to you guys doing rider mower electric conversions. It is a neat way to start learning EVs. I did one about 15 yrs ago. BUT, these things can be dangerous. They can cause injury or worse. Realize that the electric motor, like a GC motor, will provide enough torque to overpower the friction brake. The one I did had a single disc on the axle. I had an old floor sweeper motor. Those golf cart motors will have 2 or 3 times the torque. No way could the little friction brake stop the motor from propelling the tractor.

Most controllers, like the Curtis, have an input for an interlock signal. Or as I call it, a permissive signal. This input needs to be used. When the signal is not present, the controller shuts off. You need to put a microswitch on the brake pedal. And on the seat. Otherwise someone can get hurt easily. If you drive under a tree branch which is too low and it pins you to the rear of the tractor your first reaction is to hit the brake. It will not stop you unless the motor is turned off. And then if you do get knocked off the tractor, a seat switch will stop it from mowing down your children.

Be safe.

major

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Alex Everett

Discussion Starter · #17 · May 26, 2008 (Edited)

Thanks Major, for the note of caution. Safty is allways first order of business.

I had thought about that particular situation also. My solution was actually a simple one. A power cutt off safty pin attatched to a wrist rope. Yes the exact device used on my Jet Ski. It is going to be wired in to the ign switch circut to cut ign signal to the 48 volt solenoid. It will kill the motor when pulled out. I have allready wired in the seat safty swich to the same circut. Motor will not run unless DRIVER IS IN SEAT and PIN IS IN DASH.

Thanks Lexus.
I will start working on a video and get the teenager to figure out how to load it on that U-ube thing for me.

MarxNutz

· #18 · May 26, 2008

I am doing a very similar project using a 36 volt motor from an electric go-kart. My problem is that the motor has a sprocket on the shaft and it doesn't want to come off. Also, the shaft is 5/8" diameter and the original dual pulleys are for a 1" shaft. I am trying to figure out how I can mate these things, or should I do some engineering to make use of the sprocket? i.e.: mod the system to accept a chain drive?

MarxNutz

· #19 · May 26, 2008

BTW, congratulations on your test run! I'm looking forward to getting mine ready for its first ride as an electric!

talonts

· #20 · May 26, 2008

major said:
Most controllers, like the Curtis, have an input for an interlock signal. Or as I call it, a permissive signal. This input needs to be used. When the signal is not present, the controller shuts off. You need to put a microswitch on the brake pedal. And on the seat. Otherwise someone can get hurt easily. If you drive under a tree branch which is too low and it pins you to the rear of the tractor your first reaction is to hit the brake. It will not stop you unless the motor is turned off. And then if you do get knocked off the tractor, a seat switch will stop it from mowing down your children.

Be safe.

major

My wiring diagram already includes the ignition switch, seat switch, and foot pedal switch, ALL which must be on for the motor to spin - so even moving my foot off the pedal will shut it down. And I'm using a pot throttle that won't let it start at full throttle.

I believe in overkill ;-)

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