Introduction: Solar Power Cordless Lawn Mower

Picture of Solar Power Cordless Lawn Mower

Hello, and thanks for reading my 'How to Make a Solar Powered Lawn Mower.' I didn't take any pictures of it when I was building it, as I was to busy building it. I hope you will enjoy this Instructable and get some good ideas on your own project.

Step 1: The Battery

Picture of The Battery

So one night I was walking to my house and a neighbor was throwing out an old cordless lawn mower. Sweet! But there was a catch, batteries where toast. Why you may asked? Over charged from the wall changer caused the battery to swell and crack. The two bad battery's that where in the lawn mower where 12v, 10ah and need to be replaced. I made a decision to replace the old battery's with the same capacity batteries to fit in the removable battery.

Step 2: Everything I Needed

Picture of Everything I Needed

So for a long time I wanted to make solar powered lawn mower. I already have a solar panel mounted outside from another projects. My solar panel is a 12V 500ma solar panel I got from eBay. I also have a solar charger controller that works with my battery's I picked up for a kit.

KEEP IN MIND

I was hoping I could recharge my two battery's in parallel but keeping them in series but it won't work. Unless you broke the series circuit before wiring them in parallel and then breaking the parallel circuit when you want series circuit, if not, a short will happened.

Step 3: To Recharge

Picture of To Recharge

To prevent a short I have two pig tails coming from the removable battery, for each battery. To recharge the removable battery I plug my solar panel and solar battery charger controller to one of the pig tail and wait for the controller "charge" LED turns green. Once one battery is fully charged I switched over to the other battery until the solar change controller LED turns green.

When I got the new batteries I had to remake the connections to add the pig tails for the solar panels. Other than that this was the hardest part to make as the battery area was pretty small from the start and adding more wire didn't help.

Something I should add is that gel cell battery's can't take a high change current. A while ago I have read online article that was taking about the charge current on sealed gel cell. The article said that the charge current for a gel cell battery shouldn't be anymore then {C/20 = charge current} where C is the capacity of the battery. so for me my 10 amp hour battery should have a maximum change current of 500ma and I do.

Step 4: All Together

Picture of All Together

The battery takes about 2 to 3 days to fully recharge and it can fully mow my lawn with battery capacity to spare about 50%. In this picture you can see I have two solar panels connected to the removable battery. The two solar panels are electrically separated so there isn't any risk of the a short circuit. If I use the two solar panels the recharge time is about a day and a half.

Step 5: Thats It!

Picture of Thats It!

Thank you for reading my Instructable I know it's not as very helpful , but it's all I had and one day it might help somebody.

Comments

daemoncan (author)2015-09-29

Nice write-up. Where did you find the 10Ah SLA batteries. I have the same model and was forced to resort to using 7 Ah batteries due to the sneaky manufacturer tactic of using non-standard (off the shelf) battery sizes.

NRG4UandMe (author)2014-12-06

Nice write-up and way to go on recyclying your neighbor's old mower ! I just wrote up on the greenworks mower that has twice the capacity battery -- might I suggest, if you can get solar panels about $1/watt, to get 50 or 100 watts, then you can charge others things and your mower alot faster, even on cloudy days -- it's alot of fun not having to worry about a gas mower much anymore !!

NRG4UandMe (author)2014-12-06

Nice write-up and way to go on recyclying your neighbor's old mower ! I just wrote up on the greenworks mower that has twice the capacity battery -- might I suggest, if you can get solar panels about $1/watt, to get 50 or 100 watts, then you can charge others things and your mower alot faster, even on cloudy days -- it's alot of fun not having to worry about a gas mower much anymore !!

KROKKENOSTER (author)2014-09-20

This charging the gel type batteries @ C/20 amps is new because I worked with them on Pathfinder electronic steering of turret truck in warehouses maybe that was designed in but that silly 723 voltage IC gave endless problem We had to set the voltage of the 24 volt gel batteries at 27.6 volts Excellent way to use the Sun

myclangelo (author)2014-09-16

I just happen to have an electric mover with a sealed lead-acid battery with the
same voltage and wattage (even the same LED charge status display). My mower is a Riobi brand model, but I suspect they both were both manufactured by the same factory. I have contemplated building a solar charging station too and found your project to be very interesting. Thank you for taking the time to put this
together! As you said it might not be perfect but it provides just enough
guidance to intrigue folks to start looking into projects that fit their specific
mower. Since there are so many different designs for electrical movers on the market now with different battery types and supporting electronics that the best that one can hope to accomplish here is to inspire others. Great Job! Overcharging is a common problem with these older lead acid battery designs, so one of my objectives for my solar project is to build in overcharging protection. It seems that in the last 6 months or so many of the new electric mower designs have switched to lithium-ion batteries which as I understand it must be protected from overcharging by default.

DGW (author)2014-09-14

May I suggest solar panels from solarblvd.com for cheap prices. They are on eBay too. I bought an $11 solar charge controller on Amazon. Thanks for giving me ideas towards building an electric robotic mower. People should not have to spend an hour mowing their lawn in this age of technology. (Yes, I know it has been done with some measure of success.)

rnorton2 (author)DGW2014-09-15

I like where your heads at!! One less thing to do and just one time fee. and thank you jeremythesolarguy for the inspiration.

847MicRoss (author)DGW2014-09-15

I agree it should be filled with edible plants. Get some return for that patch of grass you have to pay property taxes on for sitting there doing nothing. You might as well get some food out of it.

dr_jing (author)2014-09-14

Nice work on the mower set-up, but your write-up is almost unreadable. It's as if you wrote it on your phone, and you were in a hurry.

847MicRoss (author)dr_jing2014-09-15

"Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't
mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng
is taht the frist and lsat ltteers be at the rghit pclae. The rset can
be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is
bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the
wrod as a wlohe."

I am sorry, I have a some issue with spelling and how words work. I will get a friend to look it over. Thanks for your feed back.

cbeard2 (author)2014-09-14

give him a break.... typos happen.

dick55 (author)2014-09-14

Have you read the last sentence in your Instructable? Actually very funny!

PeteJaz (author)2014-09-14

You say "change a lot and I think you mean "charge"?

bremus (author)2014-09-14

Cool, battery powered and solar charged versus using the grid.

discostu956 (author)2014-09-12

simple but effective. I guess you only mow once a week or so, so no issues waiting 3 days for it to charge. nifty!

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