RC Lawn Mower - I need your brain power. - RC-Monster Forums

Bmr4life · **RC Lawn Mower - I need your brain power. -** 04.27.2011, 04:25 PM

I've been kicking this around for years and said I would do it when I owned my own house. Well that's been over a year know, time to get started.

I see most DIY RC mowers using wheel chair motors with complicated logic boards and motor controllers.

I'd like to stick to what I know. What I need help with is knowing what size motors I need, KV, and gearing.

A 15mph top speed would be more than enough. Mower probably would weigh around 50-60lbs?

I was looking at these motors at Hobbyking. Maybe with a pair of these esc's. I actually have a pair of MMM's I could put in there, but whatever.

I know I'd need to figure some gearing out. Potentially a chain drive a with some sprockets.

Maybe I'm crazy, but I think a pair of those motors could easily handle it considering a single 2200kv CC motor can power my 15lb Savage to 50mph. As for batteries, that's no problem. I'd just put a ton of lipo's in parallel for run time.

So, anyone got any ideas?

JERRY2KONE · 04:53 PM

There have been a few of them around here in the past two years or so, but none that were terribly successful. Moving the lawn mower is not the problem. Keeping the blade moving under heavy load as it cuts through grass is. This is why even small gas mowers have 5hp-15hp Briggs & Straton motors on them. Good luck.

(http://www.rc-monster.com/forum/show...ighlight=mower)

(http://rc-dc.ch/gallery/displayimage.php?album=34&pos=1 )

(http://www.rc-monster.com/forum/show...ht=R%2FC+MOWER)

(http://www.rc-monster.com/forum/show...ighlight=mower)

(http://rc-monster.com/forum/showthread.php?t=21502)

(http://www.rc-monster.com/forum/show...ighlight=mower)

Bmr4life · 04.27.2011, 04:54 PM

Oh, well the lawn mower is still going to have its current gas engine. I'm not taking that away.

Thanks for the links, I'll check them out when I get home from work.

_paralyzed_ · 04.27.2011, 06:45 PM

I don't know why the mowers you saw had logic boards, they are unnecessary. A wheelchair motor is just a 24 volt brushed motor. A mamba monster max on 6s would be perfect for it.

Two esc's, two wheelchair motors and a tank remote and you are in business.

I have a pair of wheelchair motors waiting for a project like this. Someday....

_paralyzed_ · 04.27.2011, 06:51 PM

thinking more about it, the logic boards were probably there off the original wheelchair electronics, and they allow a single joystick throw to power both motors and track straight. Using a tank remote and seperate joysticks bypasses all that crap and really simplifies everything.

Just drive it like a skid steer.

trev3813 · 04.27.2011, 09:01 PM

Haha, wheelchairs... I have a 10 grand one in my garage i go mudding with, oh how i love expensive toys :)

Bmr4life · 09:46 PM

Quote:

Originally Posted by _paralyzed_

thinking more about it, the logic boards were probably there off the original wheelchair electronics, and they allow a single joystick throw to power both motors and track straight. Using a tank remote and seperate joysticks bypasses all that crap and really simplifies everything.

Just drive it like a skid steer.

Actually, the logic boards are after market units. Not the ones that come with the wheelchair.

I am going the two brushless motors with two esc's route. I just need help choosing motors.

Bmr4life · 04.28.2011, 08:06 AM

Bingo, got the motor figured out.

A guy using 4 of these on a mountain board was able to go 30mph. Said him plus board was about almost 200lbs. This is the motor for me.

I can put a chain sprocket on the shaft to handle power delivery and gearing.

Bondonutz · 04.28.2011, 09:30 AM

The outrunners are def much better suited for this build.

Curious to see more, get to work !

Bmr4life · 01:52 PM

Oh yeah, the plot thickens.

So now I've found some cheap 24v DC motors. They are used in electric scooters like this. If one can power 100lbs to 10mph, two in my lawn mower should be perfect. Hell, I wonder there are any esc's that can take 24v at 10 amps. My MMM's would be overkill.

steveo · 04.29.2011, 07:14 AM

are you trying to cut your grass at 15 mph or do just want to be able to drive it that fast, 2-4 mph is what you need to cut with any faster wont look so good, the mower will hop

Bmr4life · 09:14 AM

Quote:

Originally Posted by steveo

are you trying to cut your grass at 15 mph or do just want to be able to drive it that fast, 2-4 mph is what you need to cut with any faster wont look so good, the mower will hop

2-4mph, thanks. I don't plan on cutting at high speed, but I do want it to have a high speed option for getting from A to B between cutting.

Also, I picked up a used/broken Razor for $15 off CL. Hooked the battery directly to the motor and it works just fine. Probably something wrong with control module which I won't be using.

steveo · 04.29.2011, 10:20 AM

after i saw this thread i went to youtube you should do the same

Bmr4life · 04.29.2011, 10:21 AM

Quote:

Originally Posted by steveo

after i saw this thread i went to youtube you should do the same

I've seen the vids on youtube. Have you seen something in particular?