Solar Water Pump: The Definitive Guide 2020

A solar water pump system is commonly seen in residential and commercial uses, as well as for irrigation of farmland.

Solar Water Pump

Contents

Solar water Pump Introduce

The solar powered water pump is no gird electricity needed. It’s driven by DC12-110V which provide by the solar or lead-acid batteries.

Usually, a solar water pump system is composted of solar pump, controller, solar panels, and batteries(optional).

Due to it’s small size, it can convenience use in deep well, canal, or some water irrigation source.

Solar water Pump Development

The solar powered water pump which parent is the Electric powered water pump. But you know in some remote areas the gird is not adequate. So if the famer want to make a irrigation for the crop. They have to use there hand or diesel engine as the motivation.

Irrigation by hand is a ancient method, the only thing it bring you is the heavy physical labor. The diesel engine drive the water pump, the famers no need elevate water one barrel by barrel. That’s much mature method. But there some corns of that method. The system is huge do not suitable some small-scale irrigation operation. The diesel engine is a big monster, and noisy all around.

In the 21st century, the people of earth have master use the solar energy. Why not use solar powered water pump. With this curiosity, the smart people start their innovation. Especially in china

,there is a city named Taizhou, southeast of Zhejiang province which famous of electricity gadgets industry. 70% of water pump produced by that place of the world. It’s called hometown of water pumps.

How Solar water pump Works?

Solar water pumping system diagram

Solar Water Pumping System Diagram

The solar panel absorb the sunlight, and transfer to DC12V to provide power.

The electric current stream through the Controller, and the controller control the switch the water pump turn on or off.

And the lead-acid batteries is option, that can save the remnant energy which provide by solar panel. The water pump elevate the water and outlet.

How to Select Use Batteries or Not?

Even if there is no batteries as long as there is sunlight the water pump can working regularly. If you use the water pump 24/7, you best use a batteries. because the night have no sunlight.

If you use the pump occasionally. There no need use a bulk of battery. Because the batteries will increase your budget.

And some one will ask, can solar water pump work well in rainy day or cloud day. I can ensure you that it won’t work well. unless you use a bulk of batteries. Let’s talk about it.

In fact, the water pumps were more used in irrigation. We know that when it dry out we have to irrigation, the rain is satisfied with the most of the crops. It’s needs only several day to irrigate.

But the rest days the solar panel not stop working, so the solar energy will be wasted if we don’t deposit it. If your budget is adequate, you can use batteries. Vice versa, when the rainy day, we no need irrigate crops. The rain did it for us. So the batteries opiate as your wish.

The water pumps specification

There are virous types of water pump can be chosen. Check the main products below:

3 inch and 4 inch DC Solar Deep Well Pump

3-inch-and-4-inch-DC-Solar-Deep-Well-Pump

3 inch and 4 inch Dc solar deep well pump house use the stain streel martials, the outlet martial is brass. With the small size it’s convenience used in the home yard, garden, patio. It can be powered by a piece of solar panel. And it can provide at least 2 m3 water per hour for you.

3 inch and 4 inch AC&DC Submersible Solar Deep Well Pump

3-inch-and-4-inch-DC-Solar-Deep-Well-Pump

This type added a AC power supplement that ensure you can use it at night or rainy day.

You should ensue that there is AC power supply, that can be use in 110V-265V. The wide voltage ensue that suitable any country.

6 inch AC&DC Submersible Solar Deep Well Pump

6-inch-ACDC-Submersible-Solar-Deep-Well-Pump

There are 3 styles of 6 inch solar water pump, their all use stain steel material and high performance.

The 6 inch is rated 25m3 waterflow. it can use in big scenario. And it also use a AC supplement.

It needs make up a series solar panels to power the pump. So It’s a big system. Irrigated farmland is nothing more than the best choice.

How to Choose the Type of Water Pumps?

It’s depends on your using situation.

Generally, 3 inch and 4 inch water flow like a tap water, 6 inch water flow like a fire hydrant. But the deep of the well and lifting height of the water is another two important reference index. Note that flow and head are inversely proportional. Your tap water on the second floor is definitely not as large as the tap on the first floor. If you need a larger head, you can choose a large-diameter pump.

Solar Panel Selection

Before installing the solar water pump and DC controller, we should know how to select the solar panel for the solar water pumping system.

Select the type

Solar panel can be divided into thin-film photocell, polycrystalline silicon solar cell and
mono-crystalline silicon solar cell. The prices are different for the three kinds of solar panel.
Mono-crystalline type has the highest price but the efficient is the best. The thin-film
photocell is the cheapest one.

Select the rated power and Voc

Rated power: The power is proportional to the panel area. Normally, the rated power
of solar cell is 150W per square meter.

Voc: The open-circuit voltage (Voc) means the max electromotive force before solar
panel working. The common open-circuit voltage (Voc) is DC 21V, 36V, 44V, etc. The
lower the temperature, the higher the Voc. Because the open-circuit voltage changes
along with the change of area and temperature. If the Voc is not high enough, connect
more solar cells in series. The total voltage value equals the sum of each panel’s Voc.

How to select Voc and rated power?
When solar panel working, its voltage will decrease, this voltage is called working
voltage (Vmp). The Vmp of solar cell needs to be selected according to the solar
pump controller’s working voltage, and then to confirm the open-circuit voltage (Voc)
of solar panel.

After that, according to the solar pump power to select the solar panel power. The
generating efficiency of solar panel is under 70% usually. In order to ensure the rated
working time (for example 4 hours a day), the solar panel power equals to 1.5 times of
solar pump power. It is the minimum power for choose. That means, if the solar panel
power is smaller than the minimum power, the solar pump can work normally but can’t
reach its rated flow and head. The best solution is to use more solar panels if
condition permits, and it is also ensure more working time for the solar water pump.

Solar panel recommendation for 12V-110V DC solar water pump

When the solar panels are in series connection, the voltage is added, but the current isn’t
changed.
When the solar panels are in parallel connection, the voltage is unchanged, but the current is
added.
Before the power is on, you must use the instrument to detect the open circuit voltage of
solar panels, or apply for series, parallel knowledge to calculate the solar panel open circuit
voltage. The open-circuit voltage of solar array must be less than the maximum input voltage
of the controller, otherwise is will cause irreversible damage.

Solar Panel Specification

Max power: 150W Short Circuit Current: 9A Open Circuit Voltage: 22V Max Power Current: 8.4A Max Power Voltage: 18V

Max power: 265W Short Circuit Current: 8.7A Open Circuit Voltage: 36.6V Max Power Current: 7.68A Max Power Voltage: 30.6V

Max power: 340W Short Circuit Current: 9.5A Open Circuit Voltage: 46.2V Max Power Current: 8.9A Max Power Voltage: 38.2V

Solar Controller Specification

Solar Controller
  1. Nameplate and caution
  2. Operation panel
  3. DC electric cable entrance
  4. Water level sensor cable entrance
  5. Pump electric cable entrance

Working Environment and Electrical Property

Working Environment And Electrical Property

There are 2 type controller can be choose. The DC controller and the DC/AC controller. Obviously, in use the DC/AC controller you can choose connect a AC power in this system. It’s a supplement of the solar system. Especially in some high power water system or high flow system, sometimes the sunlight is weak in the morning or damn, the solar energy is not enough drive the pump working stable. So you can choose use the Ac mode to make it work well.

Batteries(optional)

If you choose use a batteries, you also have many choices. Because there are virous types batteries can suitable for the solar water pumps system. The must used is Lithium batteries and Lead-acid batteries. Obviously, the lithium batteries is more expensive. But it’s eco-friendly and smaller size, long life span then the lead-acid batteries. The price about 1.5 to 2 times of the lead-acid batteries.

The li-iron batteries life span about 3-5 years, according the batteries quality you choose. The lead-acid batteries can’t reach 3 years.

How to choose?

It’s depends on your budget, and the local government environment requirements. If the high environment requirements region such as west Europe, the US, Japan you have to choose the li-iron batteries. And if your area not high requirement, you can choose the lead-acid batteries, but you must do some protection work. We should pay attention to environmental protection.

Solar Water Pump Installation

Solar DC Controller Wiring Diagram

Solar-DC-Controller-Wiring-Diagram

Wiring Instructions

Before you star wiring the controller box switch MUST be in the OFF position. Wire the solar
pump and solar panels to the DC controller as per the wiring diagram. Make sure the pump
and controller are not touching each other. If the wiring is incorrect, the pump will run
backwards. Then exchange two wires of solar panel to the correct wiring. When connecting
with the battery, make sure the polarity is correct, “+” to “+”, “-” to “-“.
Caution:
1. When wiring a battery. Be careful not to reverse or short the terminals. We advise you
remove all metal wrist bands or watches before you start.
2. Solar PV panels connecting together can also produce a lot of energy. So operators are
more careful about wiring.
3. A dark cloth to shade the panels is good precaution to reduce the power output.

Operation

Operation Panel

 Voltage (V): Voltage indicator lights.
Speed (RPM): Speed indicator light.
Current (A): Current indicator light.
Power (W): Power indicator light.
Tank: Light when tank is filled with water.
Well: Light indicates no water in well.
MPPT: Solar energy running lights (twinkling).
Power: Light twinkles at downtime. Light is constant in running.

Set Key: Manufacturer parameter setting (not opened).

Enter: Manufacturer parameter setting (not opened)

UP: RPM setting key, each time you press, the RPM will increase
for one grade.
In fault state, turn off/on the fault display.

Down:

RPM setting key, each time you press, the RPM will decrease
for one grade.

Switch:

In the operation status, you can circularly switch the display
mode in voltage (V) -> speed (RPM) -> current (A) -> power
(W)

On/Off:

In the running state, you can turn it off.
In the stop state, you can turn it on.

Test Running

Before you testing the pump, the controller box switch must be in the off position. The pump must be under water at all times and should have been pre-conditioned for at least 15minutes. Water is the lubrication for the pump and if it is not “preconditioned” properly the bearings will not be adequately lubricated. 

Do not attempt to test pump if even for a moment without if being submerged or permanent damage will occur. You will need a large container so the pump does not pump it dry in seconds. It is used to raise and lower the pump. Never use the power cable to do this.

  1. Attach a durable rope or stainless steel cable to the top of the pump using the mounting hole. Make sure the rope or cable is longer than the depth at which you want to install the pump. This is used to raise and lower the pump. Never use the power cable to do this.
  2.  Attention Do keep the pump under water at all times when operating DO be careful with wiring DO remove the pump if not used for a long time and wipe the screw and body. Wipe with vegetable oil. Do make sure the pump has adequate water around it during pumping. Don’t run without water. Do put your solar PV panels in a sunny position facing true north (southern hemisphere) or true south (northern hemisphere). If the panel angle is fixed then an angle equal to your latitude will be a good compromise. Don’t run the pump out of the water, even momentarily. It will void the warranty. Don’t use the pump in dirty water. Premature wear will not be covered by warranty. Don’t disassemble the pump and controller.

Operation Mode

Pump Start

1.Power on to start

Every time it connects with electricity, the system default boot, and pump start immediately without testing water tank (without any shutdown conditions).

2.Key to start

In shutdown state, press the ON/OFF key to turn on the pump, without testing water tank (without any shutdown conditions).

3.Water shortage to start

If the system boot but the pump stop and water shortage switch is closed, the pump immediately starts. (TL signal terminal of the main control board is shorted to the COM terminal).

Pump Stop

1. Float Switch Mode

In running state, when the water full switch is closed, the pump immediately stops. (TH signal terminal of the main control board is shorted to the COM terminal, and the Tank light is on).

In running state, when the water shortage switch is closed, the pump immediately stops. (WEL signal terminal of the main control board is shorted to the COM terminal, and the Tank light is on).

2. Dry Pumping Shut Down

If the water pump continuous work for a period of time and the power is less than the set power at the current speed and continues for 20s, the pump will stop immediately and report P48 fault. After 30 minutes, the fault is cleared.

3. Button to Stop

In running state, press the ON/OFF key to turn off the pump.

Pump Operation

Every time the pump starts, it will recognize the DC (battery) and PV (solar) power supply mode for 10 second, and then switch to the corresponding mode to run. The setting speed is invalid during the identification process.

1. DC mode (battery)

In DC (battery) mode, the pump speed is adjustable, range of 1000-4000RPM. The default setting speed is 4000RPM. The speed can be set by the UP or DOWN keys, and the speed can be increased (or decreased) by pressing the increment (or decrement) button.

With the pump running, DC (battery) supply voltage will continue to decline to prevent excessive discharge, when the voltage is lower than the corresponding electrical protection voltage, the pump stops working.

2. PV Mode (solar panel)

In PV mode, the pump setting speed is similar to DC mode, and the maximum speed (4000RPM), limit is effective. Pump running speed is also determined by the current solar power. When the solar light enhances, the output power of solar panel increases, the pump speed increases, and vice versa. 

In PV mode, the MPPT indicator flashes. If it flashes faster, it indicates that the current working point is closer to the maximum working point. If the flashing frequency is slower or not, it indicates that the maximum power point is being tracked. 

Solar power is insufficient, the pump speed will continue to fall, when the speed drop to 600RPM, pump stops, and report P46 faults after 3 second.

When solar power is too insufficient to maintain the current system of starting or running, the output voltage of solar panels will drop rapidly.

When the minimum voltage drops to the lowest voltage of system and lasts for 10s, it will report “PL” fault. Try consecutively 5 times to restart, if it still appears “PL” fault. Hold this state for 30 min, then try to start again.

Reverse connection protect

If the positive and negative of power supply is reversed, the controller will continue to alarm.

Dry-run protection

This function refers to the pump pumps out water on well, the system can automatically detect the anhydrous state. Pump will stop working automatically by set program. Dry-run protection is effective all working modes, in manual mode, float switch model and solar mode.
Pump will standby for 30 minutes tore start the work (meet the start condition). Start to detect again whether there is water or not, if no water, stop working automatically. There is water, keep working, that cycle repeats.

Servicing and Maintenance

1. After working 3000 hours, the easily damaged parts should be replaced (such as bearing, sealing ring, mechanical seal), or it may cause much more serious damage.
2. If the pump didn’t use for long time, please scrub it, place at dry and ventilated place and keeping properly.

Final Words

This article details the development process, selection and installation of solar pumps. Especially the installation part, we have introduced a large part. If there is anything you don’t understand, please do not hesitate to contact us or leave a message in the comment area. To get the latest content, please subscribe to us.

Frank Cheung
Frank Cheung

A blogger interested in solar and LED lighting. He studies how to make people's lives greener and more environmentally friendly. Also served as a faculty member for non-profit organizations.