Green Solar Powered Water Barrel




Introduction: Green Solar Powered Water Barrel

About: 30 Year Retired Electrical technician from the Royal Canadian Navy

A Green way of using rainwater with the convenience of city water. The attached solar regenerated pump enables you to water plants with pressure, even when the water in the barrels falls low enough that it barely passes the level of the faucet. The sun-warmed water also aids in the growing of plants as it does not shock them. The twin 85 gallon barrels are raised onto a very sturdy 4x4 box assembly from recycled wood, held together with new carriage bolts because the total weight of all the water when full is approx 1700lbs. This frame is resting on eight 2 inch thick 18 inch square cement pads to prevent sinking. The barrels are raised to increase the head pressure and decrease the work load on the pump.
Vote for me if you think my idea is worth passing on to show people being green doesn't have to mean sacrificing quality or convenience . Thank you for taking the time to look at my instructable!

Step 1: Water Supplied From Mother Nature

link barrel to downspout. ensure top of barrel remains below level of water entry. I found the Watersaver attachment for the 3x4 downspout pipe works perfectly. In order to enable adequate water flow to the barrel I adapted the Watersaver attachment by drilling out the side and adding a flange for a 1inch PVC fitting. I sealed this by using a rubber gasket and additionally using a silicone sealer. Ensure there is a downward slope between the downspout and the barrel entry.

Step 2: Overflow Back to the Downspout

ensure you have a complete path for water from the downspout to the barrel or barrels then from the overflow to the downspout again.
1" pvc overflow line from last barrel back to downspout. ensure you maintain a drain angle towards the downspout or sediment could collect in the line.

Step 3: Downspout Drain Connection

1" pvc entry back into downspout. ensure pvc pipe does not fully block 2"x3" downspout and keep the downward slope to the pipe to make the water flow towards the downspout.

Step 4: Manifold

common connection point for using water.
this photo of the manifold is before I put the water gauge on. (shown on intro and last step)

Step 5: Water Filter

filter the water from the barrel to protect the pump. keeps the roof sediment from wearing out the pump. This water filter will last forever, as it has a reusable nylon mesh filter inside, that only requires periodic rinsing.

Step 6: Battery Box With Power Switch

keeping the battery and pump protected from the elements inside a full size battery case .

Step 7: Inside View of Battery Box With Motor

An inside view of the standard size battery case and equipment layout. the solar cell was left with clamp connections in order to enable quick removal of the battery case lid for cleaning and maintenance.
The pump was recycled from an older sailboat. The battery is a standard size lawn tractor 12v, and with proper maintenance should last 6-10 years before being needing to be recycled at the depot.
An older car battery that just doesn't have the power to crank the car fast anymore would be more than adequate for this application, and a great alternative to buying a new battery.
The 5.5W solar cell was also recycled for a fraction of it's original cost from an online classified, and solar cells have a lifespan of aprox 15-20 years. I wanted this little project to last as long as possible before needing any repairs.

Step 8: Flowjet Pump

closeup of Flojet 4405-143 pump particulars
another pump that I have seen that is almost identical to this is made by shurflo
This type of pump is used in RV's or sailboats to supply water pressure, as well as for using as a wash down pump on boats.
I chose this type because it had an internal pressure switch that stopped it from running all the time, only turning on when the water pressure in the hose drops. In addition I got a super deal on it secondhand.
There are many different styles of pump available that will be more than adequate for this application. It depends on your budget, and availability of secondhand pumps in your area.
Other things to consider would be whether or not you want the pump running all the time (lawn sprinkler) or only when you press the trigger on your hose nozzle. Without a built-in pressure switch, the pump would run all the time as soon as you turned on power. In all types of applications, make sure the pump output pressure does not exceed the pressure rating of your hose/pipe or you might burst it if the outlet was closed or blocked unexpectedly.

Step 9: Water Gauge

As the water level changes inside the barrel the level inside the tube will follow the same level.
This was fun to install as I didn't want to waste all the nice rainwater and drain the tank before I drilled a 3/4" hole in the bottom of the tank to install the angled shut-off valve. Reminded myself to only use a battery powered drill :)
I reused some 1/2 inch plastic tubing that I had left over from another application and connected it to a 3/4 inch angle valve with a shut off (which came in handy during install)
I sealed around and under all penetrations into the barrel (valve and screws) with a two part epoxy that was a water proof filler and sealer.
It is important to not completely seal the tube or the level will not change to reflect the level in the barrel.



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    160 Discussions

    Hello. May I ask where you got the downspout screen shown in the Step 3 picture? thx

    Where did you get these tanks?

    Great project! I think I'll incorporate the pump and charger into our rain barrel setup. Can I make a suggestion? If you use one of the RainReserve diverters, and mount it in the downspout at the level that you want the water to fill the barrels to, you can eliminate the need for a drain line. Once that level in the barrels is reached, the water simply runs down the downspout. They're also very durable; ours has withstood four rather bitter Northern Illinois winters, and we don't do any winterizing with it, it just sits there. Just a thought, thanks very much for sharing.

    1 reply

    Hey there BilgeD,

    I like your comment about the diverter. Makes kind of sense to me, but am a bit confused why that would mean no need for a drain line. Is it that the water overflow then just flows back out the diverter and down the rain spout, bc it's at the same height? Am i understanding the physics of that right? (otherwise if the diverter is too high, the pressure wouldn't allow that) Thanks a bunch :)

    Thank you so much. I have had an old Flo Jet pump for some time now wondering just how I could use it in this type of situation. Your model is excellent. The water level meter is an excellent addition. I will definitely be building this bad boy. Be well.

    Great project..!! Thanks for taking the time to document, share and answer questions. Very much appreciated.

    i was looking to put in a small submersible pump with a float that is solar powered so i don't have to do the hose siphon thing in the rain at night! any idea of a good inexpensive pump i might use?

    So, you have the solar panel clamped directly onto the car battery and the pump wired right to the terminals, too? Could you go a little more in-depth on that? Something like this would be a perfect solution for watering my grass. Thanks!

    5 replies

    from the battery positive it goes to a 10amp fuse, then it goes to a single pole-single throw switch then to then positive lead on the pump. battery negative goes directly to the motor negative lead. Solar panel positive is directly clamped to the battery positive, and panel negative is clamped directly to the battery negative.

    Another question if you don't mind: can you please point me in the right direction with respect to the battery box? I'm having a hard time finding one like yours with a switch that's also reasonably priced (and doesn't have extra stuff I don't need, like 12V outlets on the outside). Failing one with an integrated switch, any advice on how to add a switch to the mix? Many thanks again!

    Awesome setup! Thanks so much for posting this! I'm going to try something very similar with my rain barrels.

    Question though: is the 10amp fuse something I would have to buy separately, or would it come with one of the other components (pump, solar panel, battery, battery box)? If separate, anything special I should look for in buying a fuse? Also, how is the fuse connected exactly? I'm new at this type of electrical installation. Many thanks!

    Is there a diode in series with the solar panel? It might be built in, but if there isn't one, the solar panel will drain the battery at night when there is no sunlight.

    Very clean design lines. It appears the battery is exposed to the elements? Other suggestion, is to consider a filter in front of the pump inlet to capture what will be some of the roof top deposits that may be mineral components of the shingles, moss build up that flows down the gutters or other 'stuff'. A good sized clean out on the bottom to access the tank as solids build might really be good as well. Unless I am missing those in the overall design and if so.....never mind. GREAT job

    I have seen a good priced 10w solar panel, could I use this with your system? I know it needs to be 12 volt but that is about it :)

    2 replies

    sorry for the delay. but to answer the question...yes!
    Larger is better as it will decrease the recharge time of the batteries.

    Thanks for your reply, I have sourced all of the items I need and have found a great 20W solar panel. This is going to be my spring project ready for the summer. Cheers.

    Great idea. Have you considered alternative water sources when there is no or limited rain? Luckily, I live on a canal and am considering something like this to irrigate my yard so I could attach a low-volume pump to fill the barrels when rain does not. Another alternate method might be a sand point with a low-volume pump. This could have it's own solar powered unit or run off the main. I would set it up on a switch or one could put a level sensor in one of the barrels and put a limiter on the low-volume pump circuit so that it only runs when there is sunshine.

    Thanks for the idea very creative. Quick questions for you: would like to insulate it for winter but ignorant on that?

    If you look around, you can find an all plastic pump that won't rust out from the rainwater. It's important that it's a jet pump so you get enough pressure to run the attachments. Or you can get a submersible and put it in the bottom of one of the barrels. That will give you huge pressures though so you'll need a regulator. Either way, never start the pump with the attachment(s) turned off or you will get cavitation which wears out the impeller(s). If you hear a louder "swooshing" sound, turn if off right away. That means it's cavitating and you don't have enough flow on the output for that size pump.