Hello from the bottom of the Rabbit Hole!

I’ve spent most of the last two weeks putting out fires (hard disk failures, email corruption, taxes) and taking the plunge down the rabbit hole that is my riding mower.

I chose to save $1200 by buying the baby of the mower offerings and giving up some of the “features” of it’s bigger brothers. I did that with the full intention of adding those features back. This involves stripping down the mower, documenting how the cables are laid out and what controllers it’s using and then coming up with ways of adding in the features that were deleted from the smallest in the group. They didn’t give it a USB port, or cruise control, and they capped the speed at 7Km/h which I’ve since learned is a legal limit for electric vehicles that can be operated on sidewalks. This mower is actually 3cm wider than the largest mobility scooter I’ve found, will still fit through a doorway without the mower deck attached (which is how I got it into the basement) and has double the range of it’s electric scooter counterparts. Yet those electric mobility scooters cost $3000 more and aren’t nearly as solidly built. At any rate, I think there may be a “solution” to the speed limit problem too.

So, to add these “features” back and improve it further, I need to print a new control panel and probably some mounting brackets for various add-ons. I also wanted to replace the relatively “dumb” meter they had with one that could actually measure the amount of current to and from the battery bank rather than just estimating it from the battery voltage. This is what’s been tying me up for most of the last two weeks.

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Not sure I understand the endgame… is this going to be a souped-up mower in the end or are you modifying it to be an electric scooter? In any event this should be an interesting project.

It’s an electric mower. Being an Electronics Technologist I get along much better with it than I do with gas engines. I bought it because it was quite a bit cheaper than the next model up, I only have 1/3 acre to begin with, and this fits through the fence gate that divides the pool area, sheds and storage from the main yard. The downside is that it doesn’t come with all the bells and whistles that the bigger brother has. This was partly about adding back the missing features and then going above-and-beyond.

The other major reason is the power meter. The original showed “hours”,“Volts”, and “charge level”. They then proceeded only show you the volts for about 500ms during start-up and then stayed on “hours”. The charge level was a bar graph that I quickly determined is actually just a measure of volts and not the actual charge on the battery. To properly measure the charge you actually have to measure current, not voltage so one of the first things I did was to replace the meter.

Replacing the original meter means I lost the “hours” meter, so I added a separate one.

Since I occasionally find myself without a car, I use the mower as my “mini Tesla” and use it for grocery runs, however, since it’s easy for someone to just drive off with it, I added a finger print reader and “lock” button.

I added a USB port, not because I really need one, but because the bigger brother had one. The USB port I found had a built-in volt meter. So now I’ve added an additional switch to allow me to switch between each of the four individual batteries to check their respective load voltages using the USB meter while the power meter shows the actual state of charge as well as the total voltage of the entire battery bank.

Obviously, this necessitated designing my own control panel.

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That’s all kinds of awesome!!! Please share the final result - I’d love to see how it ended up!

Also - what was the original make/model? my FIL is looking for a small riding mower and battery powered might work well.

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https://www.homedepot.ca/product/ryobi-30-inch-50-ah-battery-electric-riding-lawn-mower/1001490679

I actually prefer its small size. Physically, it’s 1.5" wider than the largest mobility scooter they had at Invacare. I don’t use it as a mobility scooter, I was just curious. Mind you, it has twice the range, half the price and much better traction, especially if you put tire chains on it. I use it to plow the driveway.

Frankly, between pulling wagon loads around the yard, plowing the driveway (or soil to level the grass), aerating, de-thatching, and trips to the mall (with a wagon), I end up using it more as a utility vehicle than as a mower.

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I have it installed. I still have to work on the electronics, particularly the fingerprint reader and how to get it to lock out the power switch.

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That’s freakin’ cool! I wouldn’t know where to begin on a project like that.

Wow thats a neat project :slight_smile:

How did you implement the fingerprint reader? Through an Arduino?

Yes. It’s a capacitive fingerprint sensor from DFRobot controlled through an arduino.

https://www.dfrobot.com/product-2051.html

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