Product Review: DIY Solar Pool Pump (Almost) Changes the Game

I replaced my high-powered pool pump with one of the new solar models. It’s incredibly quiet and powerful but lacks “soft” power transitions and support.

Walk into your local pool supply shop. Ask them what they know about solar-powered pool pumps. You’ll probably get the same blank stare that I did. 

I’m not sure what the market barrier is. The technology is ripe. The biggest deterrent to their widespread adoption, as far as I can tell, is that the U.S. pool industry doesn’t make or offer them. Also, you can find a lot of negative reviews about the imported products that do exist failing after just a few months. 

That’s a shame, because, in theory, a DC brushless motor should last 20,000 to 30,000 hours with minimal maintenance. In contrast, a brushed motor typically has only a 2,000 to 5,000-hour lifespan. That's 6 to 10 times longer for DC versions. 

PV-powered water pumping in general is considered by some experts to be “one of the most promising” applications for PV panels. 

It’s possible, of course, to tie the pumps and PV panels in with battery storage, and deliver more consistent power flow, but that greatly weakens the ROI incentive. Direct power from PV should be just fine for residential pool filtration if the motor works properly.

So why all the bad reviews for these pumps? After installing one, I have a theory: There’s a technical glitch--an oversight, if you will, in how these motors are being controlled. I’ll get to that.

Where Do I Find a Solar Pool Pump?

Not many brands of DC swimming pool pumps exist. The ones I found come from Asia. That’s a bummer because U.S. companies are missing a great opportunity. My experience with my first DC-powered pool pump has been surprisingly positive so far. The thing is powerful, quiet, and runs off sunlight, as advertised.

The brand I installed was this one from Vevor, priced at $341, a 500-watt, .67 HP model. Before I go on, I should note that Vevor has a pretty lame reputation. They are ranked “F” by the Better Business Bureau and not a member, due to the more than 1,000 complaints lodged about their products and their support. 

So yeah, you’re rolling the dice buying from them. I rolled anyway.

The Vevor pump is supposed to run on 48 volts of solar. You receive a controller panel with the Vevor unit that appears (based on my observations) to automatically “step down” the power supply so that the pump operates at lower speeds when the panels are in shadow or a cloud passes. 

My two 400-watt panels have an open-circuit voltage (Voc) of 36 Volts. Connecting them in series gives me a maximum power output of 800 watt at 72 volts. What’s probably happening (the installation manual offers no help) is that the voltage, already stepped down to 48 volts, is dropping down to 24 volts. If the voltage goes lower than that, the pump shuts off completely.

So What’s the Glitch?

The glitch, if you read between the lines of the negative product reviews, is that these units sometimes fail in a fairly short period of time. That’s usually the sign of excessive stress on a DC motor. Various other details of the installation may influence this, such as excessive moisture.

I think the reason is simpler: The pump is cycling on and off too frequently, responding almost instantly to sunlight variations with no real buffer. Left to its own chicken-sized brain (actually a small circuit board), on a cloudy afternoon, my Vevor pump tends to shut down for 10 or 20 seconds, then run for 5 seconds, rinse and repeat--until the sun finally goes down completely. That can’t be good for the DC motor. 

I’ve created a workaround for this problem with a timer, but let’s set that aside for now and crunch some numbers.

What’s the Payback?

To estimate the return on investment (ROI) period for my new DC solar-powered pool pump system, I need to calculate the initial investment versus continuing to operate the old AC pump. Here's a step-by-step breakdown:

Initial Investment: PV plus DC Pump (and Timer)

• Two 400-watt PV panels: 2 x $220 = $440
• Cabling for PV: $25
• 500-watt DC Pool Pump: $341
• Circuit Shut off/timer: $75
• Total Initial Investment: $881

Energy Savings Calculation

To calculate the savings, we compare the energy consumption and cost of running the old single-speed, 110-volt, 1 hp, 750-watt AC pump to the new .67 HP DC solar-powered pump. The savings will come from the reduced electricity bill by using solar power instead of grid electricity.

Old AC Pump Energy Use

The energy use of a 1 hp (horsepower) pump running for 7 hours a day. The formula to convert horsepower to watts is 1 hp = 746 watts. So, a 1 hp pump uses 746 watts or 0.746 kilowatts (kW).)

• Two 400-watt PV panels: 2 x $220 = $440
• Daily energy consumption = 0.746 kW x 7 hours = 5.222 kWh
• Assuming an average electricity cost of $0.13 per kWh (this rate can vary greatly by location), daily cost = 5.222 kWh x $0.13 = $0.679
• Annual cost = $0.679 x 365 days = $247.835

New DC Pump Energy Use

The new system uses solar power, and I only run it when the sun shines, so the direct electricity cost is $0. To calculate savings and ROI, we consider the reduction in grid electricity use. That makes our annual savings: $247.835. Now divide the total initial investment by the annual savings, to arrive at a 3.55-year payback.

* Note that I did not include every incidental cost, such as the fasteners for the solar panels, schedule 40 plumbing to reduce replacement of flexible hoses, etc.

Huge Potential, But Chaotic Consistency

That’s a pretty short payback period. In fact, if the pump were to live up to its brushless potential of 20,000 hours, it would last about 8 years. 

At that point, I might need a new pump, but I’d still have the whole solar setup, with another 15 years of solid performance, so the price of a replacement DC Pump would be my only cost. That cuts my payback ROI for the second pump to 1.3 years. 

At every stage, I’d be keeping tons of CO2 pollution out of the atmosphere, yet still enjoying my decadent Western amenity.

This technology needs to become mainstream if pools are to remain a morally conscionable feature of American homes during this Climate Emergency. It should be an easy lift for a good manufacturer to start building them. 

Here are three low-hanging corrections a new player could make, which are currently holding back the market:

1. Pick a Price. Nobody seems to agree on what these DC pumps are worth. Here’s another solar pump with similar specs to the one I bought, selling for nearly $1,000. The market has not found a settling point in price. 

Either somebody is making a killing retailing this model, or there’s something magical about it that makes it cost triple what my model did. I couldn’t tell from the few specifications offered why one model would be superior to another, but the cheap model obviously has a much better sustainability story to tell.

2. Hire an Expert Technical Writer. No one seems to be able to translate these products into plain English. Expect to do some head-scratching as you leaf through the DIY installation guide for a pump like mine or the one I just mentioned. 

One of the buyers of the $1,000 version above (Lori Lucas) gave it 4 out of 5 stars because the documentation was “horrible or non-existing.” She noted that she liked the price of the unit (this was the $1,000 product), but couldn’t get a live person on the line to help her.

My model had similar weirdness in the brief instructions. It interchanges two different types of pump illustrations and offers precious little troubleshooting guidance, operational tips, or more nuanced help.

3. Fix the Cycling Glitch. The problem of the motor cycling on and off needs to be corrected. It’s damaging to the equipment and probably just a matter of putting in a smarter circuit board in the controller. There’s no excuse for not correcting this immediately. 

What I’m doing with mine, incidentally, is introducing a digital timer between the panels and the controller. It simply cuts off the power at the point in the late afternoon when the panels begin to run inconsistently. It’s not a perfect fix but better than allowing the device to burn out way too quickly.

An Opportunity for Solar Pool Pumps to Shine

There’s no reason some smart U.S. companies couldn’t engineer variations on these DC pool pumps. A frequently referenced figure from the Pool & Hot Tub Alliance (PHTA) and other industry analyses suggests that there are over 10 million residential swimming pools in the United States. 

Additionally, there are upwards of 300,000 public swimming pools across the country. These numbers include both in-ground and above-ground pools but can vary based on the criteria used (e.g., size, type, and usage).

So come on folks, who wants to get rich while creating a product that will vastly reduce the CO2 footprint of pools?