What measurement photo voltaic water pump do you want?

Photo voltaic water pumps proceed to develop in recognition, and for cause — they’ll deal with any water provide challenge, from home provide to large-scale irrigation. That mentioned, the wrong-size photo voltaic water pump can flip a clever funding into an enormous headache.

As a potential photo voltaic water pump purchaser, it’s worthwhile to familiarize your self with all the required sizing information. Belief us after we say there’s greater than sufficient incentive to take action.

Failure to buy the proper measurement pump can lead to pointless return journeys to the shop, delivery returns, and, worst of all, you being left with a pump that can’t fulfill your water calls for.

Let’s take a better have a look at how one can keep away from these nightmare situations. 


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Photo voltaic water pump measurement: desk

The next desk highlights the water calls for and corresponding photo voltaic water pumps for various measurement households.

Water wants Amount of water per day Sort of water pump Pump energy (DC) Pump voltage (DC)
Small home (2 folks) 120 gallons (454 liters) Submersible 50W-150W 12V- 30V
Home (household of 4) 300 gallons (1135 liters) Submersible 50W-250W 12V- 30V
Home+ (household of 5 + swimming pool) 450 gallons (1703 liters) Submersible 150W-270W 12V- 30V
Circulation pump for swimming pool 4500 gallons per hour (18m3/hour) Above floor 500W 48V
Agricultural irrigation 5000 gallons per hour (20m3/hour) Submersible 1500W 110V

What measurement photo voltaic water pump do you want?

To find out the scale of the photo voltaic water pump you require, perform the next:

  • Minimal pumping movement: Calculate the minimal pumping movement out of your day by day water wants.
  • Complete dynamic head: Calculate the whole dynamic head from the depth of the nicely and the space from the water supply to your storage cistern or home.
  • Appropriate photo voltaic water pump: Supply the proper pump with matching specs.
Solar water pump diagram.
Photo voltaic water pump diagram.
Supply: researchgate

1. Calculate the minimal pumping movement

To calculate your minimal pumping movement, you could estimate your water wants.

Let’s assume your photo voltaic pump will function throughout peak sunshine hours — between 9 AM and three PM (360 minutes). In case your family consumes 300 gallons day by day, that’s 0.83 gallons per minute (300 gallons/360 minutes=0.83).

Variable energy

As it’s named, a photo voltaic water pump wants photo voltaic panels to perform. Photo voltaic panels are variable energy mills — their energy output varies all through the day and yr. Consequently, a photo voltaic water pump’s water manufacturing additionally varies.

This will develop into problematic as your water wants are comparatively secure, although there may be usually a rise through the summer time months.

The most typical answer to a variable water provide is to retailer water in a cistern. As a rule of thumb, we advocate a 7-day water storage capability.

A household of 4 utilizing 300 gallons day by day would want a cistern of 2100 gallons.

2. Calculate the whole dynamic head

To appropriately measurement your photo voltaic water pump, you could think about the depth of your nicely and the friction from the pipes that slows the water movement. In different phrases: the deeper your nicely and the longer your pipes, the larger your water pump should be.

Pump producers generally use the whole dynamic head (TDH) to calculate the impression of friction loss on the water movement.

TDH = Static head + Friction loss

To calculate the whole dynamic head, you’ll want the next:

  • Static head: That is the space between your nicely’s water stage and the highest of your water tank.
  • Friction loss: This pertains to your pipe’s sort, size, and diameter.

Be aware to our readers: Estimate your friction loss right here.


Your nicely is at a depth of 70ft. Your cistern is on the identical stage, positioned 200ft away out of your photo voltaic pump. Due to this fact, the TDH is:

 70 + 0.14 = 70.14 ft

On this configuration, you’ll should search for a photo voltaic pump with a minimal movement price of 0.83 gal/min and a dynamic head of 70.14ft.

3. Discover a matching photo voltaic pump

You may choose the proper water pump with the minimal pumping movement price and the whole dynamic head.

Photo voltaic water pumps are specifically designed to work at variable energy. You’ll have to take a look at their efficiency chart exhibiting the water movement within the pump energy and the dynamic head perform.

With this configuration, you’ll should search for a photo voltaic pump with a minimal movement price of 0.83 gal/min and a dynamic head of 70.14ft.

Solar water pump flow chart.
Photo voltaic water pump movement chart.

On this instance, the 12V DC water pump meets the water provide necessities (70ft, 0.83 gal/min) with an influence of solely 24W (2.0Ampsx12V=24W).

What measurement photo voltaic system does your water pump want?

Now it’s time to measurement your photo voltaic system. Doing so will assist you to present your pump with the required quantity of energy.

First, collect the next data:

  • Pump energy at minimal water movement and complete dynamic head
  •  Photo voltaic panel hourly energy profile

The movement chart within the earlier part indicated that the pump is able to assembly the water provide necessities — 0.83gal/min, complete head of 70.14ft — at an influence of 24W.

With a 30% additional energy margin, the photo voltaic panel ought to provide at the least 32W between 9 AM and three PM. Now, it’s time to pick a photo voltaic panel that may fulfill this energy requirement.

To do that, you could extract a photo voltaic panel’s hourly energy profile at your nicely’s location. You will discover this data utilizing the photo voltaic calculator from World Photo voltaic Atlas.

Enter your location and the photo voltaic panel’s energy, and the calculator will present an entire report of your potential photo voltaic manufacturing.

On this instance, we examined a 100W photo voltaic panel in San Francisco. This photo voltaic panel will fulfill your necessities from 9 AM to three PM, even all through winter. 

The hourly power profile of a 100W solar panel in San Francisco, California.
The hourly energy profile of a 100W photo voltaic panel in San Francisco, California.
Supply: World Photo voltaic Atlas

In conclusion, to produce water for a household of 4 within the San Francisco space, you’ll solely want one 100W photo voltaic panel coupled with a 12V photo voltaic water pump.

Do water pumps use lots of electrical energy?

A DC photo voltaic water pump makes use of thrice much less electrical energy than an AC water pump of the identical pumping capability.

Naturally, the deeper your water nicely, the extra electrical energy your water pump will use.

Within the earlier part, we demonstrated that for a household of 4 with a 70ft nicely, the water pump makes use of 24W for six hours. That’s solely 144Wh per day (24Wx6hours). As compared, a family-size fridge wants about 1200Wh per day.

Remaining ideas

In abstract:

  • To amass the proper measurement photo voltaic water pump, you could estimate your minimal water movement and the water elevation (dynamic head) from the underside of your nicely to your home or cistern.
  • By estimating your location’s hourly energy output profile, you may decide the quantity of solar energy essential to run your water pump.
  • DC water pumps don’t use lots of electrical energy. 
  • The pump makes use of 8 instances much less electrical energy than a fridge to meet a household of 4’s day by day wants,

In case you have any additional questions, please attain out to us within the feedback part or comply with us on Twitter.

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