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If you live in a rural area or need to access water underground, you’ll need to buy a well pump. Unfortunately, water pumps use a lot of power and could drive your electric bill sky high. That’s why it’s no surprise that many are asking, can you run a well pump on solar power?
A 1/3 HP well pump needs 3000 watts of solar power. The pump only uses 750 watts to run, but the motor requires 2-3 times as much power to start up, so ten 300 watt solar panels that produce 3000 watts is needed.
How Many Solar Panels Does a Well Pump Need?
To answer that question we need to know the power requirements of a well pump. These pumps come in various shapes and sizes, but their wattage use are in this range. The table below provides an estimate of how many solar panels each pump needs.
As you will notice, he starting watt capacity can be two or three times the running watts. We listed the solar panel requirements for starting watts that are three times higher than running. But if your well pump only need twice the starting watts, you can reduce the number of solar panels.
If you have a 1/2 HIP well pump for instance, you need 7 or 14 x 300 watt solar panels, depending on how many starting watts is required. We suggest going with Renogy 12V Monocrystalline Solar Panels because they are proven effective and reliable. Bear in mind these are only meant to give you an idea. You should check the product specs for more details.
|Solar Panels Needed
|10 x 300W
|14 x 300W
|15 x 300W
|20 x 300W
|1 1./2 HP
|25 x 300W
|38 x 300W
|50 x 300W
|75 x 300W
|7 1/2 HP
|100 x 300W
|117 x 300W
Now all you have to do is get a solar power source that meets those requirements. Note that there are two numbers on the chart, the running watts and starting watts, just like a solar powered air conditioner. The starting watt is what a well pump needs, to initialize, similar to a refrigerator. The running watts is what a well pump consumes while it runs.
How to Calculate Solar Power Requirements of a Well Pump
The table above gives you a good place to start. But if you want to do the calculations manually, this guide can help. We need to clarify a few things first.
Well pump starting watts = solar panels needed
Well pumps do not run continuously, with most running for 20 to 25 minutes an hour. So a 750 watt pump might use 320-350 watts. But its starting power requirement is still 1500 or 3000 watts. that is why you should still have at least 3000 watts of solar power.
3000 watts is the minimum required. If you can get more power, add more. A 10 x 3000 watt solar array is going to produce 30000 watts an hour if they perform at peak level. If the panels drop the output will drop below 3000 watts.
it should b pointed out that the starting watt requirement is only for a second. Once the motor starts the pump is going to run 750 watts or so.
This means the solar panels do not need to produce 1500 or 3000 watts continuously. All the pump needs is 750 watts to keep going. This also means the rest of the solar power is free and can be used to run other appliances and devices.
To keep it simple: check the starting wattage of the well pump. Once you have that, you can determine how many solar power watts or battery size is needed.
Do You Need Batteries to Run a Well Pump on Solar Power?
Running a well pump solely off solar panels means you will not be able to use the pump at night or if it is raining. A battery allows you to run a well pump even if there is no sunlight to power the solar panels.
You charge the battery with solar panels and then run the pump off the battery. This way you can use the well pump anytime, day or night regardless of the weather.
The battery size depends on how long you run the well pump off the battery. If you use a 1/3 HP pump for an hour, you will need a 150ah lithium battery. We like the Eco Worthy LiFePO4 12V as it has a long lifespan and runs very well with well pumps.
The longer you run the pump, the more battery power is needed. You can settle for a smaller battery bank if you combine it with a solar array. But it is more practical to use the panels to charge the battery and run the well pump off it. Unlike solar panels, batteries will run even without sunlight and in any kind of weather.
it does matter whether you use a solar array or a solar generator. As long as the system meets the wattage needed, the well pump will run. How the well pump runs though, will depend on whether you use an AC well pump or a DC well pump
AC vs. DC Well Pumps – Which Runs Better on Solar?
There are two types of well pumps you can choose from, AC and DC. Each has its own pros and cons and you have to decide which will work best for your situation.
one of the benefits o fusing a DC well pump is you can run it directly off a solar panel. if you have an AC pump, an inverter is needed to convert DC power into AC. But AC pumps are more common and you can plug it into an AC socket if there is insufficient solar power available.
DC Well Pump
- Does not require an inverter or battery
- More efficient than AC well pumps
- Ideal for small to medium scale projects
- Runs quietly
- Not widely available, may require special orders
- Requires thick, long wires to run, which is expensive
- Large capacity models can be hard to find
AC Well Pump
- Widely available
- You can run it off 120 or 240V
- Runs on higher voltage than DC, uses thinner and cheaper wires
- More affordable than DC well pumps
- Needs an inverter to run on solar, which is expensive
- Not as efficient as DC well pumps
- Requires a large battery bank and/or solar panel
Some well pumps can run on AC or DC, hence the term flexible. It’s not yet commonplace but it’s something to consider. If you’re connected to the grid a flexible well pump could be to your advantage. At least you have the option to run the pump on a battery, generator or on the grid, depending on your needs.
A hand pump is not advisable because they are only good for for a depth of 25 feet. All deep water wells for human consumption are much deeper, hence a submersible pump is required. You could use a hand pump for emergency or backup, However that water is not considered fit for consumption by humans.
Solar Pump Kits. These are all in one solutions containing all the components you need to run a well pump on solar power. Is it right for you? It depends on your situation.
A solar panel kit is for you if you require a self-contained system to pump water. If you’re a rancher or own some farmland, an all in one kit will save you a lot of trouble.
A solar pump kit is not for you if you already have a solar system at home. It’s cheaper to just expand your solar system (add panels, batteries or a generator) than install a kit. it is also more practical to add more components this way than set up a new system based on the kit.
How to Install Solar Power for a Well Pump
If you already have a solar powered well pump, it’s just a matter of assembling the parts. But converting your existing well pump is not that difficult either.
Solar Pump Kit: if you bought a solar pump kit, all the required parts are there. Follow the instructions in the manual and you should be ready in no time.
DC Well Pump Solar Power Installation: find out how much solar power your pump needs. Set up the solar panel, battery or solar generator according to the manual. You can connect the well pump directly to solar power. Unlike AC powered devices which should not be directly connected to solar power, you can hook up a DC well pump directly to solar.
AC Well Pump Solar Power Installation: connect an inverter to the solar panel. Connect the well pump to the inverter using the appropriate wirers and connectors. If you’re using a solar generator, the inverter is already built-in so you just need to connect the well pump to the system.
What are the Benefits of Solar Powered Well Pumps?
Advances in solar technology have made them more accessible to a lot of people. Solar power provides a lot of benefits, and this applies to well pumps too. To lowering the cost to making pumps easier to operate, there is no shortage of advantages to going with solar.
Solar power is easy to install, even for well pumps. Solar pump kits come with every wire, connector and part you need. You can connect a DC well pump directly to a solar power system. A AC well pump just needs an inverter and it’s ready to go. You can of course run an AC well pump on any wall outlet.
Solar power well pump installation shouldn’t take more than 20 minutes. The solar panels, sensors and pump are joined together by screws, so it’s simple. Even submersible pumps designed to go a hundred feet plus deep have a straightforward setup.
Solar panels are easy to clean and low maintenance. You just need to wipe the panels clean once or twice a year and it will run fine. The pumping component should last tat least 5 years while the solar panels are good for 10-25 years.
Complete Systems are Available
You can put together a solar powered well pump, but all in one solar powered pumps are now being sold. Just like solar pump kits, you can put these components together in no time. And thanks to competition, the cost of these systems are going down faster than before.
No Ongoing Expenses
Why do people love solar power? Because once you pay for the system, there are no more bills to pay. You have free energy. That applies to solar powered well pumps too. Once you pay for the pump and the solar system, that’s it.
As long as the sun shines, you’ll be able to use the well pup at no cost. If you connect the pump to a solar battery you can run it any time, day or night. The money you spent will pay for itself quickly as water gets pumped out quietly and efficiently.
Whether you convert an existing well pump to solar or buy a solar powered unit, there’s no questioning its efficiency. Well pumps are essential to many homes, and fortunately you can use solar power for it. As technology improves, expect efficiency to improve even more.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.