EcoRider - riding lawn mower electric conversion - Page 8

Daox · 06-10-09, 07:30 AM

Welcome to ER cgates30. Your setup would be very similar to mine being a two belt system. I suggest you start your own thread and post up some pics and we can work out any kinks and questions you have.

A golf cart motor may be good, but from my ebaying, they usually don't have an end on one side since they mount up to a transmission or differential. This means you'd have to make your own which is really not easy unless you have access to metalworking machinery.

You're right, a controller would be nice but is totally unnecessary once you size your pulleys right.

cgates30 · 06-10-09, 08:54 AM

I'm hoping the pulleys don't need to be replaced. My idea is if the motor speed is +/- 20% of the gas engine speed then everything should scale accordingly.

Will do on the thread, just need to get some pics, etc.
Thanks

Daox · 06-11-09, 10:59 AM

Well, I stopped at the local bearing place last night. I walked in, told them what the bearings were for and was asked if I wanted the imported ones, or nice ones. After a pretty short discussion, I ended up going all out and getting the very nice sealed Timken bearings. The guy basically assured me that they'd never go bad. So, $120 later, I have 6 new bearings to pound into the mower bearing carriers. This puts the total project cost at right around $160. That includes the pulleys and bolts/washers.

I'll get pics when I start the work which will hopefully happen this weekend. I really want to hook it all up and see if it made any difference. I also want to hook it up @ 24V and see what kind of amperage it pulls since that puts my rpms back in line with what they're supposed to be. That should give me a much more accurate idea of what my amperage would be if I decided to stay at 36V with properly sized pulleys.

Daox · 06-17-09, 07:54 PM

Tonight was a quick job. I got all the spindles together and degreased them since the new bearings are fully sealed. Then, I sharpened the blades. They weren't horrible, but they definitely weren't sharp.

Daox · 06-23-09, 06:17 AM

This past weekend was another build day. Unfortunately, I forgot my camera again! I did get the whole deck put back together. It just needs a new belt and then it needs to be put back on the tractor. After that, I need to load test it once again and figure out my battery setup.

Here is a picture of the new/old bearings.

Tango Charlie · 06-23-09, 10:05 AM

Quote:

Originally Posted by Daox

...Unfortunately, I forgot my camera again! ...

D'oh! That's grounds for a lynching, mister! Ha ha!
Good to see the project progressing, anyway.

Daox · 06-23-09, 02:08 PM

Well, I could argue that this really isn't part of the conversion, just part of owning a 40 year old mower!

Daox · 08-03-09, 11:40 AM

I finally picked up a new mower deck belt last night. I have no idea why it took this long. I've gone out to work on the mower several times since the last update only to think 'DOH, I need a belt!' By the time the next day rolled around, I had forgotten about it and thus it never got done. So, reassembly will be underway very soon.

Daox · 08-04-09, 08:55 AM

Its almost all back together. I need to stop on the way home and pickup another new belt. The motor must have moved forward a bit compared to the gas engine, so I need a longer drive belt.

Daox · 08-06-09, 09:30 AM

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 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.

06-10-09, 08:54 AM	#72
cgates30 Lurking Renovator Join Date: Jun 2009 Posts: 3 Thanks: 0 Thanked 0 Times in 0 Posts	pulleys I'm hoping the pulleys don't need to be replaced. My idea is if the motor speed is +/- 20% of the gas engine speed then everything should scale accordingly. Will do on the thread, just need to get some pics, etc. Thanks

08-06-09, 09:30 AM	#80
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	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 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. Last edited by Daox; 08-06-09 at 09:32 AM..

06-10-09, 07:30 AM	#71
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Welcome to ER cgates30. Your setup would be very similar to mine being a two belt system. I suggest you start your own thread and post up some pics and we can work out any kinks and questions you have. A golf cart motor may be good, but from my ebaying, they usually don't have an end on one side since they mount up to a transmission or differential. This means you'd have to make your own which is really not easy unless you have access to metalworking machinery. You're right, a controller would be nice but is totally unnecessary once you size your pulleys right.

06-11-09, 10:59 AM	#73
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Well, I stopped at the local bearing place last night. I walked in, told them what the bearings were for and was asked if I wanted the imported ones, or nice ones. After a pretty short discussion, I ended up going all out and getting the very nice sealed Timken bearings. The guy basically assured me that they'd never go bad. So, $120 later, I have 6 new bearings to pound into the mower bearing carriers. This puts the total project cost at right around $160. That includes the pulleys and bolts/washers. I'll get pics when I start the work which will hopefully happen this weekend. I really want to hook it all up and see if it made any difference. I also want to hook it up @ 24V and see what kind of amperage it pulls since that puts my rpms back in line with what they're supposed to be. That should give me a much more accurate idea of what my amperage would be if I decided to stay at 36V with properly sized pulleys.

06-17-09, 07:54 PM	#74
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Tonight was a quick job. I got all the spindles together and degreased them since the new bearings are fully sealed. Then, I sharpened the blades. They weren't horrible, but they definitely weren't sharp.

06-23-09, 06:17 AM	#75
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	This past weekend was another build day. Unfortunately, I forgot my camera again! I did get the whole deck put back together. It just needs a new belt and then it needs to be put back on the tractor. After that, I need to load test it once again and figure out my battery setup. Here is a picture of the new/old bearings.

06-23-09, 02:08 PM	#77
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Well, I could argue that this really isn't part of the conversion, just part of owning a 40 year old mower!

08-03-09, 11:40 AM	#78
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I finally picked up a new mower deck belt last night. I have no idea why it took this long. I've gone out to work on the mower several times since the last update only to think 'DOH, I need a belt!' By the time the next day rolled around, I had forgotten about it and thus it never got done. So, reassembly will be underway very soon.

08-04-09, 08:55 AM	#79
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Its almost all back together. I need to stop on the way home and pickup another new belt. The motor must have moved forward a bit compared to the gas engine, so I need a longer drive belt.