How to Run a Well Pump on Solar? The Ultimate Guide
Is your conventional well pump consuming a lot of power and draining big from your grid system as well as your pockets? Here’s a cheaper alternative you should consider:
Converting your AC power well pump to solar and running it with the free energy of the sun.
- 1 How to Run a Well Pump on Solar? The Ultimate Guide
- 1.1 What is Solar Well Pumping/Types of Solar Pumping Systems?
- 1.2 Can Well Pumps Run on Solar Power?
- 1.3 Why do you need a Solar Well Pump?
- 1.4 Solar Well System Pump Kit
- 1.5 Running a Well Pump on Solar (A step by step process)
- 1.6 Installing Surface well pumps
- 1.7 Installing Submersible well pump
- 1.8 Solar Well Pumping System Maintenance
- 1.9 Solar Well Pump Backup
- 1.10 Wrapping Up
And here is the most interesting part: You only need an inverter to convert the DC power from solar panels and batteries to AC for your upgraded well pump.
If you’re a beginner in well pumping, you can invest in a DC well pump kit and tap into solar energy from the word go.
There’re endless benefits of a solar water pump. It can run off-grid and provide water even in the driest remote areas, not to mention that you can use it when there’s a power outage.
Now I know the kind of questions running in your mind:
- Can my well pump really run on solar?
- How do I size solar panels and batteries for my solar water pump?
- How do I install a solar-powered well pump system?
Well, if you have these questions, then we have an ultimate guide for you.
What is Solar Well Pumping/Types of Solar Pumping Systems?
Solar well pumping is using electricity from a photovoltaic array to run a motor pump system that draws water from a well.
There’re 3 common types of solar well pumping systems:
- Submersible pumps,
- Surface pumps,
- Floating pumps.
Following is a description of each of these pumping systems.
|Type of the pump||Location of the water pump||Location of the solar PV array||Location of pump controller||Suitable for||Special note|
|Submersible well pumps||Within the well||Near the top of the well||Near the solar PV array||Deep wells||The solar pump should be powerful enough to pump water out of your well.|
|Surface pumps||At a section above the water level.||Near the water pump.||Near the solar PV array||Shallow wells||A suction pipe must be connected to the pump to draw water from the well.|
|Floating pumps||Mounted on a floating surface with the pump within the well.||At a section above the water level||Near the solar PV array||Open wells||A flexible pipe is crucial to respond to changes in the water level.|
Can Well Pumps Run on Solar Power?
Definitely! And this will happen either directly (DC power) or indirectly (AC power).
Indirect solar power (AC well pump)
If you have a pump already installed for your well, high chances are it’s an AC pump.
To run your well pump that’s strictly AC on solar, you need to invest in an inverter. An inverter is a solar power component that transforms direct current to alternating current.
While an inverter isn’t an inexpensive component, the cost-saving you’ll have by investing in it is definitely worth it.
Pro: Cheap initial cost
Con: The upgrade to solar comes with extra costs
Direct solar power consumption (DC well pump)
The second option is to use DC power directly from your PV array to draw water from a well.
You can invest in a DC solar well pump designed specifically to use solar power if you’re starting out.
Pro: Expensive to acquire
Con: High efficiency
A bonus option: Flexible solar pumps
These are water pumps that can use both AC and DC to pump water from a well.
Pro: Highly convenient since it’ll continually function even when there’s a power outage or insufficient solar power production.
Con: Average efficiency
Why do you need a Solar Well Pump?
There are more than enough reasons why you need a solar well pump, but here are the 4 primary ones:
- It’s a practical method of well pumping (It has been used for quite some time to pump water in remote areas, mainly for agricultural purposes)
- It’s a perfect off-grid water pumping solution
- You get emergency power for well pumping
- You’ll save a lot by cutting your electricity bills.
Now that you know why solar well pumping is crucial, here’re the components you should get with about any solar well pump kit.
Solar Well System Pump Kit
Solar array includes the photovoltaic panel and the supporting structure needed to keep it properly tilted to the sun. Any electrical wiring needed for the setup is also part of the solar array.
Pump – The pump is the motorized device used for drawing water from the well. It has an inlet that goes into the well and an outlet that directs water to the storage tank.
MPPT – A Maximum PowerPoint Tracker need not be defined. It’s just what it implies- a component that tunes the power produced by solar modules and converts it to the best voltage and current for the load (the well pump).
Pipes – These are the interconnections between the water source (in our case, the well), the pump, and the storage tank.
Inverter – The inverter converts DC to AC, and you’ll need it when you want to run an AC water pump with solar.
Batteries – Batteries will come in handy if you need a backup solution for your solar power array (i.e., power to pump water when there’s insufficient sun).
NOTE: I’ve mentioned the storage tank several times above, but it’s, of course, not part of the solar well pump kit. You have to install the tank as you construct the well for water storage purposes.
Running a Well Pump on Solar (A step by step process)
Before we discuss the steps, I must mention that this is quite a technical process.
Therefore, you’ll need the input of a well-skilled drilling contractor and an experienced solar contractor.
Additionally, if you have an AC pump already installed, you should skip the steps about setting up the pump.
Now let’s dive right in.
1. The design step
This is more of a research and evaluation step. Essentially, you’ll need to determine the following in this step:
- Average solar irradiation of the area where your well is located.
- Perfect location for the solar array.
- Best orientation and tilt of the solar array.
- Ideal location for the solar pump and pump controller.
- Length of cables and size of pipes needed based on the two factors above.
- Maximum flow rate and the expected frictional losses.
- Expected dynamic head (the maximum height that the water from the well will be pumped) taking into account the frictional losses in the pipe).
2. Selecting the most suitable solar well pumping system
If you’re looking for a solar water pump for your well, this should be your major consideration:
The well pump should match your well type, its location, dynamic head, and flow requirements.
The good thing with solar water pumping system manufacturers is that they provide software to help you select the most suitable pump for your needs.
3. Selecting and installing the PV array
First, you should understand that a DC well pump comes with enough solar panels to power it. Additionally, it’ll come with all the mounting components and mounting guidelines.
On the other hand, if you want to convert your AC pump to solar, you need to work with a solar technician to determine the number and size of solar panels you’ll need.
Generally, though, the power output of the solar panel should match the wattage of the pump.
If your AC pump is 100W and a single solar panel is 20W, then you’ll need 5 such modules.
To install the modules, start by first fixing the supporting structure, which can either be fixed-ground or pole-support. With this secured, you just need to mount the solar panels.
The best tilt angle for optimum power production is 10°. This angle will also optimize the self-cleaning process of the solar panels by rain.
This is making the necessary connections needed to integrate all the solar water pumping components.
Generally, you’ll follow the manufacturer’s guidelines to make these 3 main connections:
- PV array to pump controller
- Pump controller to pump
- Earthing of all exposed metal module frames
Tip: Ensure that all the connections are well-supported and mechanically protected from damage.
5. Pump controller installation
Just a refresher- a pump controller is essentially an MPPT for a DC well pump and an MPPT and inverter for an AC well pump.
Regardless of the configuration, a solar well pump controller should be mounted on the frame or mounting pole of the solar array.
Manufacturers’ recommendations (including the ingression rating, which should be a minimum of IP56) should also be followed.
6. Well pump/ pipes installation
Here, the installation will vary with the kind of pump you’re dealing with.
Let’s discuss surface and submersible well pumps.
Installing Surface well pumps
For surface well pumps, you should:
- First, construct a supporting base, preferably one of concrete. Note that elevating the pump reduces vibrations that may interfere with the surface water pumping.
- Then use a sheet metal cover to shield the water pump from direct sunlight.
Follow these recommendations when installing the suction pipe:
- Keep it lower than the inlet of the pump to prevent the trapping of air bubbles.
- Keep the length of pipe as minimum as possible.
- If the pipe must be longer than 3 meters, ensure it’s buried to prevent water heating. This can damage the pump.
- Ensure that the end of the suction pipe has no debris that may cause blockages.
- The discharge pipe should be installed continually rising to the tank with no bends.
Installing Submersible well pump
For the submersible type, here are some recommendations when installing the pump:
- Ensure the pump is 1 meter (3.3feet) above the well’s bottom.
- The pump should be below the drawdown level so that the pump never operates dry.
- Include a water sensing system to prevent the pump from operating dry.
- Support the weight of the pump with a cable fixed on the borehole cap.
When installing the pipes, follow these tips:
- Screw the discharge pipe to the pump to support its weight.
- Install a non-return valve to the discharge pipe just above the submerged pump.
- Install a gate valve to the discharge pipe just above the well exit point.
That’s it! You can now commission your solar well pumping system and get water pumped to your storage tank, leveraging the sun’s free energy.
Solar Well Pumping System Maintenance
Installing your solar water pumping properly is crucial, but focused maintenance is what will make it run properly.
Generally, the PV array will take up the biggest section of the maintenance process.
You’ll need to:
- Clean the solar panels
- Inspect for any loose connections and fix them
- Confirm that the array produces its expected output
- Check and confirm that there’re no mechanical damages to the wiring
For the pump, you should follow your manufacturer’s recommendations- the maintenance practices differ from one pump design to another.
The pump controller should be kept clean and in ambient conditions. Similarly, you should ensure that there’re no loose connections or damages to the cables.
Solar Well Pump Backup
It’s good practice to have a backup for your solar power well pump. The best backup is definitely investing in solar batteries.
When it comes to sizing the batteries, you should follow the same process for solar panels. Simply ask yourself this question:
How much solar power does my water pump need?
If you have a 220V well pump, then you’ll need a battery system that will provide that amount of Voltage. Similarly, a 12V well pump will need a 12V battery backup.
A hand pump can also act as a backup for your solar well pump. It’ll be a hustle to get water with it, but at least, you’ll not go back to relying on the grid.
There you have it. You now know how to use solar power to run your well pump.
In summary, you only need to properly select, size, and install a solar PV array and pump controller to run a well pump with solar.
If you’re starting out, I would advise that you go for a DC well pump so that you eliminate the extra cost of installing an inverter for an AC water pump.
Nevertheless, if you already have an AC well pump, running it on solar power still makes sense.
By powering your well pump with solar, you’ll save a lot and have something you can rely on to pump water when there’s a power outage.