solar lawn mower

Great Instructable!!!! I do have a few questions, hopfully it is not in the comments below but; how long does the battery supposing it is fully charged support mowing? How long can a fully charged battery by any means cut what square meter or square foot of grass, how high, and how long? My family has many acres, my parents have about 4 acres(my father cuts).
It would be interesting to mount more batteries on this unit, how many can it support? I wonder how much for a riding mower, and how much energy it would require? since the mower is moving at low speed I suppose weight does not have much of an effect. what horsepower is the lawn mower you are using? Again great job
-Inductionmind

60 square feet/55.7 square meter. Nice, again very nice instructable.

for a moment there, the panel looked like a flat screen! i could see it now! "you dawg, we put a flat screen on your mower so you can watch Weeds while you mow!"

Actually solar energy is 1kw per Sq Meter.

Congrats on the win! Someday, would you make a quick vid/slideshow of how easy disassembly is? I think it's a big selling point.

a lawn mower for 75 dollars? man isn't 'junk' awesome

So, before I start, how long does the charge last?

Sorry if I missed this already but how many amps will that solar panel put out? What is it advertised at?

you should add a switch to switch between charging mode and cutting mode. you wont have to re wire every thing every time.

Ill make a schematic and post the image here... right now I can't because this computer has no photoshop.

Another thing you can do is throw out the 2 batteries get another 12 volt solar cell put the 2 12 volt solar cells in series to get 24 volts and cut the grass on a sunny day without waiting for the batteries to charge.

Sorry. Not enough Amp-Hours. Assuming that the sun produces about 300 watts per square meter, and most electric lawnmowers use about 18 amp-hours, AND that most solar panels are @ 20% effiency, you would need about 3.6 (about 1.897 x 1.897) square meters of photovoltaic panel(s). Thats a big solar panel.
(For americans it's about 6.22 ft x 6.22 ft.)

It recharges the batteries... it doesn't directly power it. He's right. You would need a lot of solar panels to directly power it.

Regardless of B.S. this is a great idea. I've been looking at battery powered lawn mowers, and this takes the cake. 5 stars.

And you are basing this on...?

your name?

What you have here is a solar powered charger, not a lawn mower without a battery. What he was describing up there was without a battery.

rcmaniac,

"Another thing you can do is throw out the 2 batteries get another 12 volt solar cell put the 2 12 volt solar cells in series to get 24 volts and cut the grass on a sunny day without waiting for the batteries to charge."

I was explaining to him why his plan wouldn't work.

nope. yours will work perfectly fine.

Rcmaniac10,
I would like to know more about how to construct this 24 volt set-up. I'm impatient and don't have all day for the batteries to charge. Do you have a schematic ora written process. I've never done anythign liek this before. Thanks.

Wait a minute is the motor ac or dc? if its ac you can't put the 2 solar panels in series because they give of energy in dc unless you get a circuit to change 12 volts dc to 12 volts ac.

If the motor runs on batteries, the motor is always DC. when you have a motor that gets pluged into the wall of your house it is always AC current. you can get a converter to convert 12 volts DC from a car battery to 120 Volts AC. people usually use them when they go camping. so if this motor runs on batteries it is DC.

Um, not quite, there are "universal motors" that run on AC or DC. They're relatively common in handheld power tools like drills, grinders, Dremels, etc. For jobsite applications you could have a generator (perhaps an arc welder/generator combo) supplying DC for tools and lights, using normal AC plugs and outlets. Before "gee-whiz" solid-state inverters this was pretty common. If the tool has brushes and an AC plug, check the labeling to see if it specifies AC only, could say AC/DC or nothing and be universal.

there are also motors that are called brushless DC motors. These are anything but DC.
You cannot hook these to a battery directly. The controller output is a 3 phase AC power and that is why you only need to reverse 2 of the 3 wires to reverse the motor.

Brushless DC motors are brushless... they are much like the ones used in PC fans and such. Read this for more info.

I meant to say they are DC, not brushless (duh).

[www.linkintech.com/wordpress</a>]

corrected link on my last comment

I think the first send didn't work. Anyhow, now I've forgotten my comment. This is cool but I want a cheap way to convert my electric plugin mower to solar. the cord is a Pita..pain it the butt...and I cut it the other day...solar is the way 2 go but maybe its gonna cost more than buying a battery operated mower..I just paid $179 for this electric plugin. Its great except for the lousy cord. If it cost $600 to make it solar, then I should just stock up on more extension cables..and be more careful...the wordpress link is my own blog..that's what I'm talking about..great instructable but won't work 4 me unfortunately...

I'm in need of a new mower, and have been considering a battery powered one. Not much grass, usually mostly weeds. :) They are kind of expensive, and not real thrilled with the reviews. Will probably take the plunge sometime this month. Most seem to be 24 volts, so will use 2 solar panels in series. Will also use a charge controller, as batteries are expensive to replace. With the charge controller, you can leave the panels hooked up between mowings (week/months), and the batteries won't overcharge. Pretty easy to do in Florida. A robot mower would be awesome, but would still think it necessary to supervise, might get stuck, fallen tree limb, beer bottle over the fence, neighbor's cat... Also, if you don't have a fenced in yard, it's bound to attract attention and admirers. Would think it kind of dangerous for toddlers, and old men...

Where did you get that cute pink lawnmower from anyway?

if you could only run a alternator off the shaft and then weld and mount it to the front,. I was thinking of making a battery starter with a push mower and an alternator but now im looking for solar panels and a battery powered mower lmao

With this, my mower can now go off the grid...
I bought a 24V Earthwise mower this spring just for kicks and it really did a great job mowing. It takes two days to mow; one hour on the front yard, recharge for ten hours, and one hour on the back yard. Thats ok, though, cause I dont want to mow all that in one day anyway.

why did you cut the ciggarette lighter plug out of the law mower, couldn't you have just wired a male cigarette lighter plug directly into the panel

You could use a large 12volt automotive relay and not have to mess around with moving wires for charging. Attached is a wiring diagram.

I saw this on Hackaday.com.

You only need a double pole double throw switch to be able to switch between charge and mowing.

Your schematic will work if you don't have the panel mounted to the mower. I guess I was thinking of leaving it mounted to the mower.

Add a three pole switch and have the third pole disconnect the solar cell in mow position.

i guess you beat me on putting the schematic

Ahoy,
any information you or anyone else can offer on converting a corded electric mower to cordless (battery/solar like this one would be cool)?

Thanks! Great instructable.

I've been thinking about doing just that. It should be possible to run the corded mower from an inverter. I have a very healthy one (12VDC to 120VAC @ 1000Watts). Probably overkill - I haven't got my hands on an electric mower yet to look at the required power. I'd like to also convert the mower to be free running or programmed so it could run itself. The "automatic mowers" on the market ($1,500 & up) use a perimeter wire to limit their mower's cutting area. This should be doable on a homebrew basis.

Anyone else have thoughts?

Probably a bit simplistic but using 120V and 12A (my mower has a 12A motor) in this website:
http://www.jobsite-generators.com/power_calculators.html

gives me 1440 watts. Dunno if that's 100% accurate though.