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What dimension photo voltaic water pump do you want?

Photo voltaic water pumps proceed to develop in recognition, and for a great motive — they’ll deal with any water provide mission, from home provide to large-scale irrigation. That stated, the wrong-size photo voltaic water pump can flip a smart funding into a giant headache.

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

Failure to buy the right dimension pump may end up in pointless return journeys to the shop, transport returns, and, worst of all, you being left with a pump that can’t fulfill your water calls for.

Let’s take a more in-depth have a look at how one can keep away from these nightmare situations. 


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Photo voltaic water pump dimension: desk

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

Water wants Amount of water per day Sort of water pump Pump energy (DC) Pump voltage (DC)
Small home (2 individuals) 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 dimension photo voltaic water pump do you want?

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

  • Minimal pumping move: Calculate the minimal pumping move out of your each day water wants.
  • Whole dynamic head: Calculate the whole dynamic head from the depth of the effectively and the gap from the water supply to your storage cistern or home.
  • Appropriate photo voltaic water pump: Supply the right pump with matching specs.
Solar water pump diagram.
Photo voltaic water pump diagram.
Supply: researchgate

1. Calculate the minimal pumping move

To calculate your minimal pumping move, 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 each 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 operate. Photo voltaic panels are variable energy turbines — 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 typically a rise in the course of the summer season months.

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

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

2. Calculate the whole dynamic head

To accurately dimension your photo voltaic water pump, you could take into account the depth of your effectively and the friction from the pipes that slows the water move. In different phrases: the deeper your effectively and the longer your pipes, the larger your water pump should be.

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

TDH = Static head + Friction loss

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

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

Word to our readers: Estimate your friction loss right here.


Your effectively is at a depth of 70ft. Your cistern is on the similar degree, situated 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 need to search for a photo voltaic pump with a minimal move price of 0.83 gal/min and a dynamic head of 70.14ft.

3. Discover a matching photo voltaic pump

You’ll be able to choose the right water pump with the minimal pumping move price and the whole dynamic head.

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

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

Solar water pump flow chart.
Photo voltaic water pump move 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 dimension photo voltaic system does your water pump want?

Now it’s time to dimension your photo voltaic system. Doing so will allow you to present your pump with the mandatory quantity of energy.

First, collect the next info:

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

The move 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 a minimum of 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 effectively’s location. Yow will discover this info utilizing the photo voltaic calculator from International 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: International Photo voltaic Atlas

In conclusion, to provide 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 a variety of electrical energy?

A DC photo voltaic water pump makes use of 3 times much less electrical energy than an AC water pump of the identical pumping capability.

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

Within the earlier part, we demonstrated that for a household of 4 with a 70ft effectively, 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.

Last ideas

In abstract:

  • To accumulate the right dimension photo voltaic water pump, you could estimate your minimal water move and the water elevation (dynamic head) from the underside of your effectively to your own 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 a variety of electrical energy. 
  • The pump makes use of 8 instances much less electrical energy than a fridge to meet a household of 4’s each day wants,

When you have any additional questions, please attain out to us within the feedback part or observe us on Twitter.

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