Archives

Since I purchased my first house about six months back, I knew I would like a riding mower to mow its roughly one acre of land. I had finished up the fall of the year with a borrowed push mower. And, while it was possible, it was kind of a pain and took quite a while. So, I decided I wanted to go with a riding mower. It also dawned on me that small engine emissions are really bad, and there was no reason that this mower couldn't be electric powered. So, I began the quest to convert this riding lawn mower.

http://ecorenovator.org/pictures/house325.jpg



I picked up the mower for free (thanks to freecycle.org) during fall of last year. It has been sitting most of winter and this project has finally hit the top of the 'to do list'. I also just picked up a motor, contactors (massive relays), and batteries that I'll be using. So, this project is building up some steam and ready to get going.

I'll be documenting most of the progress on EcoRenovator's forum (http://ecorenovator.org/forum/projects-improvements/161-ecorider-riding-mower-electric-conversion.html). I'll probably post here to give sporadic/major updates.

Here is a teaser picture. And, no the motor isn't in upside down, the motor has two output shafts. :)

http://ecorenovator.org/forum/attachments/projects-improvements/117d1235132155-ecorider-riding-mower-electric-conversion-ecorider-021.jpg

My dad bought a Simplicity riding mower sometime in the early 70's and it is the only mower he has ever used since. It doesn't look as nice as yours anymore but it still runs. Can I have your throw away parts? Seriously you could sell the engine on ebay to fund the conversion. - Dale

Tim, you always have the most interesting projects! I look forward to more pics here when you've got it completed (as I can't see the ones over at the other site without registering).

Thanks Sean. I love tinkering. :) I also just moved my pictures to a public folder. You should be able to see them now.

drimportracing, the engine was given back to the original owner. It was fairly new and that was the requirement should I take the mower. That worked for me! The throw away parts I was planning on selling via ebay/craigslist/whatever. However, there really aren't that many. The only extra parts I have at the moment are the gas tank, starter solenoid, and the ammeter (which only goes up to 10A). I may or may not part with the throttle/choke control as I don't know if I'm going to use a controller yet. The current plan is to run without one, but we'll see.

Funding of the project has been great so far. I've stuck $0 into parts. Everything has been donated thus far. If you want to be picky, you could count the gas spent to pick the stuff up.

Much better, Tim. Good stuff! :D:thumbs_up:

Daox,
After I previously posted I went to the other site and saw how you were getting some great hookups from Ben and others for your project, that is so cool. If I remember correctly I saw a 450 Honda motorcycle in one of your pictures, could this be a future candidate for an EV motorcycle?

Good luck on your project and like Sean said post some pics here so we can live vicariously through your efforts. - Dale

Hi Tim:

___Indeed, good luck with this as it is indeed a super-worthy goal! Having ridden any number of the Big-Rig mowers the past few years, what a plants surprise when all you are going to hear is the blades vs. the 3,600 RPM engines running flat out.

___Good Luck

___Wayne

For some inspiration, I present to you the Heavy Metal Garden Tractor. The only EV tractor with a 144 W stereo system and a 10 disc CD changer http://www.evalbum.com/38

Haha, thats quite the fancy mower! I'm just looking forward to getting mine working. :)

Wayland's creations are ahead of the game. His profession is a fork truck technician and I'm sure the majority of it is in electric.

We are all anxiously watching for your progress!

Well, I just got back from my first ride on the mower!!! I got a big 'ol silly grin on my face and I'm loving it. Still needs a lot of work, but its getting closer. :D

http://ecorenovator.org/forum/projects-improvements/161-ecorider-riding-mower-electric-conversion-5.html#post3128

Oh, SWEET!!!! :D:thumbs_up:

More updates. I decided to rebuild the deck to hopefully lower the amperage draw it takes to spin the blades up.

http://ecorenovator.org/forum/projects-improvements/161-ecorider-riding-mower-electric-conversion-7.html

Daox,

Coolness! When you get your rpms to your correct range do you think that it will have enough charge to mow your entire yard in one cycle? Would a potentiometer reduce rpms without having to reduce the number of batteries? Would it be more storage, less output? I'm not sure.

How about charging the batteries with solar panels. You could mount smaller panels on the hood and build a shade canopy out of a large 200w panel. There would be no need for a trailer full of batteries, speaking of batteries, how hard would it be to get lithium battery packs? :D - Dale

Lowering the rpms to the deck and drive will definitely lower the amperage for using the mower. Unfortunately, I don't have a full set of deep cycle batteries yet. The goal really is to mow the entire yard in one cycle, and it is completely doable. It just takes a bit of tinkering to get there is all. The more I read about battery technology, the more I learn its more about making semi-accurate guesses than it is about cold hard formulas.

I can not simply use a pot to reduce the rpms since I don't even think you can buy pots that handle 100 amps. The solution there would need to be a PWM controller for a golf cart or something. I'm trying to avoid this though as it adds cost to the project and I'm really looking to keep the cost low.

Charging with solar would be the ideal plan in the end. I have looked into it a bit. The first step is to get the mower working. I'm currently charging the batteries back up with the two 12v chargers I have laying around.

A lithium pack would be great. But, again, its the cost issue. Lithium is very nice, light, and also very expensive. Lead is heavy and cheap(er). I have a few feelers out to see where I can pickup some deep cycle lead acid batteries in the area.

The goal really is to mow the entire yard in one cycle, and it is completely doable...

My question is:
How big is your yard?

I'm pretty sure I wouldn't be able to do this as one yard=one cycle.

The area I mow is just under an acre.

Unless your yard is gigantic, you can convert to EV. You just need more or higher capacity batteries (more $). The GE elec-traks from the 70s, a commercial built electric tractor with many attachments, can easily mow 2 acres.

The area I mow is just under an acre.

Unless your yard is gigantic, you can convert to EV. You just need more or higher capacity batteries (more $). The GE elec-traks from the 70s, a commercial built electric tractor with many attachments, can easily mow 2 acres.

Well... Part of my yard is now going to be allowed to go wild, but that still leaves just over 4 acres to mow.

I would be mowing much less than that if the subdivision bylaws didn't require it.

4+ acres, and a subdivision with mowing requirements? Bummer of a combination! I have 3 acres, but I can let it go if I want. (at least until the neighbors start offering to mow it themselves! :D)

4+ acres, and a subdivision with mowing requirements?

Yeah. The subdivision is ~0.25 square mile with 13 lots (~160 acres total). Ours is the smallest lot at 5.5 acres.

The largest lot is allowed to put in an ultralight runway! It's about 30 acres set up in a long, rectangular shape.

The two areas I no longer mow are way in the back and next to the wooded section of our neighbor.

And we are working on many more trees in the yard. This place used to be a wheat field.

When all is said and done, an acre of garden, another acre for scattered fruit trees, and 1.5 acres left wild will leave me with only 2 acres to mow.

You guys have huge lawns!! :eek:

My parents' house down in SC is on a 1/2 acre lot and my house sits on approximately 1/3 acre. I use a push mower and typically finish mowing in just under 50min.

Well... Part of my yard is now going to be allowed to go wild, but that still leaves just over 4 acres to mow.

I would be mowing much less than that if the subdivision bylaws didn't require it.

Wow, thats quite the lawn! Too bad about the bylaws. You could always mow the grass in two cycles. I'm considering that if batteries becomes too large of a pain to find.

I also just dropped $120 on very nice sealed Timken bearings last night. I took apart the deck last weekend and found that about half the bearings were bad. This is by far the most I've spent on the mower thus far. Grand total puts me at about $160 into it. The original goal was to keep it under $300, or the price of a semi-decent used gas mower. Thankfully, the only thing left to get is batteries.

The mowing deck has been rebuilt for a while now. I've been slacking (actually busy with other stuff) and haven't worked on it recently, until now.

Test number two went off last night. I lowered the voltage and only used two batteries instead of three. Oddly enough, my amperage was lower than with three batteries (which is opposite of what it should have been). My guess is that the lower motor rpm really helped out. At 36 volts (3 batteries) the motor spins 1.5 times as fast as 24 volts (2 batteries) since rpm is proportional to voltage. At 24 volts, my motor rpm is much more in line with what was originally intended for the mower. The result was driving around still took 20-25A, but the mowing deck only took another 25A! This is HALF the amperage of the last test. It seems that the deck rebuild and proper pulley sizing really works out well. I am very excited about this!

The next step is to procure some actual deep cycle batteries. My power died off insanely fast because I just used two semi-dead staring batteries. One trip around the house and they were already puking on me. The local battery store has some group 24 deep cycles for $70 which seems pretty reasonable. I'll have to look into what else they have too. I might want to go with something larger. I'd ideally like a 1 hr run time. At 50A, I would get about 40 minutes of run time since you don't want to cycle batteries beyond 50% to retain good life. The alternative is to go back to 36 volts, but resize my pulleys. This theoretically would drop my amperage down to ~33A. This would (again theoretically) give me right around an hour of run time and maybe a bit more because of the peukert effect. So, 36 volts is looking like the way to go.

Any thought of using 2 24V pairs in parallel? Extra battery to buy and carry, but the pulleys can stay the same?

That is definitely an option. However, it'll depend on the availability of batteries.

I got a chance to do some actual mowing last night! The mower works great despite still needing a bunch of things tweaked. Ben Nelson was kind enough to lend me some of his extra batteries for testing. I even got some video. :)

http://ecorenovator.org/forum/projects-improvements/161-ecorider-riding-lawn-mower-electric-conversion-10.html#post4019

Sweet! I just have to wait for my Lawnboy to die... ;)

Looks like its time for the monthly update of this thread. :) For those who would like to catch up quickly, I have actually written a blog series that sums it up fairly quickly.

EcoRider blog series (http://ecorenovator.org/series/ecorider/)

More in depth info is available in the build thread (http://ecorenovator.org/forum/projects-improvements/161-ecorider-riding-lawn-mower-electric-conversion.html) on ecorenovator. Or, you can ask questions here.

I also recently made an evalbum page (http://evalbum.com/2984) for the mower too.



Okay, on to the updates! :)

At the end of last month I picked up the batteries that I'll be using on the mower. They are group 31, 150Ah flooded batteries. I picked them up from a local fork lift repair place. They did blow the budget for the project kinda as they are new. But, with the life I expect out of them, I'm not going to worry about it. I couldn't find any good sources for used batteries at the time.

http://ecorenovator.org/pictures/ecorider058.JPG



Last weekend I started the battery racks. I went with two in the back for traction, but one in the front to keep some reasonable distribution of weight (no wheelies!). The rear rack is all done, but the front one still needs to be made. I like how the rear rack will give me very easy access to the batteries for checking the water level. The one up front won't be quite as easy to check since it'll be under the hood.

http://ecorenovator.org/pictures/ecorider074.JPG

http://ecorenovator.org/pictures/ecorider077.JPG



I'm really looking to get this thing running soon as I need to cut the grass before the snow starts to stick. My in laws recently took back the push mower we had borrowed from them so I have no way of mowing right now.

However, I'm also a bit excited to see the snow fly so I can get a chance to try out this attachment I got a few weeks back. :)

http://ecorenovator.org/pictures/ecorider056.JPG

The front the battery rack was made over the weekend. Here are some pics.


I started out again making it a bolt on item. This will allow me to modify or alter things as needed. Its also easier to make it since it won't be welded right to the chassis.
http://ecorenovator.org/pictures/ecorider079.JPG




http://ecorenovator.org/pictures/ecorider081.JPG




http://ecorenovator.org/pictures/ecorider083.JPG




http://ecorenovator.org/pictures/ecorider082.JPG



I was also able to do some actual mowing over the weekend as well. I wasn't able to do the entire lawn all at once, but there are a number of factors working against me right now. There is still a bunch of tweaking to do!

It's really coming along nicely. Did you resize the pulleys for the 36volts? :D - Dale

Nope, not yet. That is one of the more important tweaks to do. :)

Daox, your mower conversion looks great. Would you be able to assist me in sizing a motor and then perhaps finding some prices on one?

If so, my application will be an old mtd 18 hp with a 46" deck. Are you using a 2 hp motor to replace the gas job? My mower rarely takes 5-8 hp to do it's job with the gas engine.

I was thinking to match the engines rpm (it may be around 3600) so I could leave the tractor/pulleys, ect. alone. I have no idea how much hp I need though and the voltage can be probably from 12,24,36,48 volts.

I'm still in the tire kicking stage, but your project inspires me to do some checking.

Thanks.

Sure nidly, I'd be happy to help you out. I'm no expert, but I know a thing or two.

I've heard that a general rule of thumb is take your gas horsepower and divide by 3 to get roughly what you want your electric motor's horsepower to be. I am actually a fair bit underpowered according to this formula. My motor is rated for 1.6 hp and the gas engine was originally an 8 hp engine. My motor did get warm while I was mowing, but not hot. From talking with other owners, a warm motor is fine, just as long as its not too hot to touch. So, there is definitely some play in that formula. Of course, it will depend on your motor too. Bigger motors with bigger brushes are more capable of producing more power than they are rated for. If the motor does get too warm, you can always add a fan to it for cooling. Its not the most efficient option, but a lot easier than finding a new motor!

Matching the motor rpm to the gas rpm is necessary. However, you can fix that with different pulleys if necessary. My motor is rated for 3200 rpm @ 24V. Since I'm running 36V it is running 1.5x as fast. So, I'm running around 4800 rpm right now. Lemme tell ya, that deck will REALLY shoot that grass out. :) However, running everything that fast is sucking the amps, so I'll be lowering the rpms back down where they should be.

As for voltage, I would see how many batteries you think you can fit on the mower. If you can go to 48V thats a good thing since it'll lower your amperage which minimizes the peukert effect (discharge a lead acid battery 2x as fast and it lasts less than 1/2 as long) and you'll get longer run times. Just keep in mind how this will effect motor rpm.

Yep, gotcha. I can fit as many batts as I need since it will not have a driver (radio control saves weight)

I may look for a 48 volt motor with about 4-6 hp then. I'd like to use all stock pullys and speeds since they are about right for good mowing. I can just slow the tractor down if need be.

Now to find a used/surplus of dc motors and some kind of controller, hehe. This will be as much of a "radio controlled" project as it is an "electric conversion" I'm hoping that losing a 200pound rider will make a big difference.

One thing I'm worried about is keeping the batteries in balance since there may be 4 in series. I guess it is no different than 6 series cells (in one battery) though.

Yeah, since a 12V is just a bunch of series cells, balancing really isn't a big issue with lead acid. Every once in a while you can just top them off individually. Or, just use individual chargers.

I can tell you right now, saving 200 lbs isn't going to save you hardly anything. On my mower, just driving around the yard pulls ~25A, but engaging the blades and mowing takes an additional ~75A. So, the majority of the power is going to the mowing deck.

Yep, thanks for the info.