this Instructable will show you how to mow you're grass using solar power to charge the mowers batteries
Step 1: What you'll need
-battery operated lawn mower
-12 volt solar cell
-wire (red and black)
-multi meter
-multi tool (I used my leatherman)
-12 volt solar cell
-wire (red and black)
-multi meter
-multi tool (I used my leatherman)
Step 2: Wiring
you'll need to cut off the cigarette lighter plug in and then strip your wires .you will also need to cut two lengths of red wire and two of the black and strip both ends of those .when using stranded wire its best if you pull the insulation away slowly as you twist it to keep the wires neat
Step 3: Connecting the wires
locate the positive and negative terminals on each battery and connect the wires accordingly .it uses two 12v batteries connected in series circuit and you have to undo that connection .and wire it in parallel circuit to charge .then you must undo that and reconnect it to mow
Step 4: Bring out the solar cell
now that you have those connected you will need to connect the red wires together and connect the black wires together
be sure you disconect the the jumper wire so theres no short and the solar cell is able to charge the batteries
once thats done you'll need to connect the solar cell to leads
be sure you disconect the the jumper wire so theres no short and the solar cell is able to charge the batteries
once thats done you'll need to connect the solar cell to leads
Step 5: Charging
once you've hooked it all up all you need to do now is set it in the sun and let it do its thing .it doesn't have to be a cloudless day for your solar cells to work but they do work best in direct sun .it takes about 4-6 hours to charge depending on how clear the day is and position of the sun in reference to the solar cell .and it is about to cut thick grass for 20-30 minutes on the mulch setting so that time would be greater if you were collecting it in a bag
the solar cell does not stay connected for use of the mower (it is only for charging) .and the batteries have to be hooked back up to the manufacturer's specs .but for free power the 3 minutes it takes to do that is worth it
.it only took me about 45 minutes to complete this project since I had all of the stuff just laying around (my father is a "junk" collector)
I'm sure you will be able to locate a battery lawn mower online .my dad bought this one on clearance for somewhere around 75 dollars ,and you can purchase a 12 volt solar cell for around 65 dollars from harbor freight
I hope this is helpful and I would like any feedback and criticism you would like to offer as this my first instructable
the solar cell does not stay connected for use of the mower (it is only for charging) .and the batteries have to be hooked back up to the manufacturer's specs .but for free power the 3 minutes it takes to do that is worth it
.it only took me about 45 minutes to complete this project since I had all of the stuff just laying around (my father is a "junk" collector)
I'm sure you will be able to locate a battery lawn mower online .my dad bought this one on clearance for somewhere around 75 dollars ,and you can purchase a 12 volt solar cell for around 65 dollars from harbor freight
I hope this is helpful and I would like any feedback and criticism you would like to offer as this my first instructable
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If you want to make it you need a 12 V Solar Panel
Here you need a cheap Solar Panel
You can use Surplus Solar Cells You can get pay back in 1-2 years
There is an Engineer from Chicago his name is John Sommer
He explain it All in his Blog http://topdiysolarpanels.com/
Using push mower with a dc motor of (T)hp, a blade length of (U) a battery with (W) amount of joules is able to cut X meters of grass of w\ length by Y density =Y. all that has to be entered is the variables, and we can make good predictions of the area that could be mowed assuming the batteries are fully charged and the grass is as wet as the control condition, lets assume dry.
You do know the amperage of a solar panel if you know the wattage and what kind of battery it was designed to charge. A 12v panel in the full sun will probably charge at about 16 volts. WATTS = VOLTS x AMPS, so 5watts = 16volts x AMPS. Solving for AMPS, you get about .3 or .35 amps from a 5 watt solar panel.
I'd recommend DIYers look at the voltage that goes into their mower from the wall AC adapter. If the adapter says DC out - something like 26 or up to 30v DC out, then you can simply put 2 '12v' solar panels together in series to double their voltage. (Think of how you put two AA batteries together to get 3 volts.) Then find the adapter plug that is identifcal to the one on your AC adapter and attach that to your solar panels. The molex.com website is very helpful in tracking down the odd adapter plugs used by Black and Decker and will let you order one free!
I'd also recommend when shopping for a used mower to start this project that you choose a single battery (12v) model. It removes the need to put the panels in series. I have a black and decker single battery model and have had a 5 watt panel (now 10w by connecting 2 identical panels in parallel to increase the wattage without changing the voltage) charging my mower for 3 years winter and summer. After buying the molex connector, I just plug the panels into the female receptacle in the exterior of the Black and Decker mower. It handles the power maintenance, though my panels both DO have blocking diodes to prevent power going the wrong way - if the mower doesn't do that itself.
In my case I was lucky. The battery is a 26amp hour battery and will run for about 50 minutes and was in great shape 3 years ago - and is still in 'okay' shape now. You should keep your lead acid based batteries on trickle/solar charge all the time, rather than charging them up and storing them till use. Also, try not to use up all of the charge ever - the battery will last a bit longer. Any body have any good 'This mower runs on SOLAR" stickers?!
I've been tinkering for a while with the Arduino microcontrollers which will serve nicely as a 'brain'. I've also just started out with stepper motors coupled via an EasyDriver stepper driver, which as the name suggests, is VERY easy to hook up.
It'll likely be less of a mower, more of a 'grazer' I think. ;)
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Time to charge depends on size of panel size of battery depth of discharge and available sunlight. HE is in texas he gets a lot more sun than for example ME in pennsylvania.
Assuming FULL depletion 3 weeks to recharge the batteries in PA 1 week in Texas. I assume he does NOT use 100% of the batt cap to cut his grass so probably 4-6 days to recharge which is fine since I assume he does it once a week.
Overcharging. he is only putting in 2.5 watts AT PEAK (sun directly overhead) at that charge rate its a virtual FLOAT charge and he has almost zero need to be concerned about over charging.
ask the manufacturer about how thick the grass it will cut he did not design or build the mower :-)
IF you can find a battery electric mower that WILL meet your demands what you do is GET that mower and then use his instructable to convert to solar charging.