Solar pool pump questions

I have a 15 x 30 above ground pool (4 ft) which is about 11,000 gal. I currently use a 1.5hp pump and sand filter and it works just fine. I would like to switch over to a solar pump system over the winter. It's difficult for me to grasp what kind of setup I need for this task. I have a building with plenty of roof available for the panels, but I just have no idea what size system I need for this.

I'd be fine with it just running when the sun is out, but then again, I would really like a system that could be run 24x7 if I wanted it to.
I know some folks here are into the solar world, and I'd love to get some good advice on this, so at the very least I can understand the mechanics of what I'm trying to accomplish.

one system I found but have no idea if it's enough.

a reply to: network dude

Not sure what all equipment is involved, but you may wish to check the MTBF for the components beyond the solar cells that actually convert the collected "energy" into something that electrical devices like the pump can use.

I've heard ~ 10 years for systems that power houses, and that replacing the electronics for the system can be quite expensive.

Disregard if I'm mistaken in this case.

Cheers

a reply to: network dude

The first thing you need to do is figure out how much usable solar power you have falling on your roof, because that will determine how many solar panels you would need. That link you provided to the solar electric powered pump says that it does NOT include the panels. Probably the first step would be to search online for a free solar energy calculator. Find one that asks for your zip code, because that should take into account your latitude and average amount of sky cover due to clouds. That will tell you how many Watts of solar energy is falling on a hypothetical 1 square meter of ground, at your location. You might not actually get that much power in practice once you take into account which way your roof is facing and whether there is any shading due to trees or other structures.

Here's a free online calculator:

www.solar-estimate.org... 0CPU%2FMOB%2FTAB%20%2430%20tCPA%5D&utm_term=solar%20panels&utm_content=CPU%2FMOB%20-%20solar%20panels%20-%20broad

The most accurate way to get this number is to ask one of the solar power companies in your area for a free assessment. They can get a satellite image of your property and run it through a computer program that will show which parts of your roof would receive enough sunlight to pay for the cost of the panels. The problem with this approach is that once those companies have your name and phone number they will keep pestering you to let them install the system for you.

As a rough approximation, residential roof solar panels typically come in sizes around 200W output, so you might need a minimum of 6 or so for your application. And they would put out that power only at times of peak insolation--so definitely not a 24/7 proposition. If you want to be able to pump water more nearly continuously, you would need to double or triple the number of panels and add some battery storage capacity.

You're probably looking at a minimum of 2K$ worth of solar panels, not counting installation.

If your just looking to keep it from freezing, I'd check out a bubbler.
For filtering idk, 1.5 hp has a decent draw.
Up north we have some big boats that stay in the water all year, a bubble rig like a drip irrigation hose is weighted down around the perimeter of the hull, it bubbles up and stops all freezing around the boat out to a couple feet.
There are some low draw air bubblers out there too.
Heating for swimming, good luck, Id go gas for that

a reply to: Mandroid7

no, looking to install new pump, and power it with solar so the filter can run without power from the grid.
I plan to install over the winter and run it when the pool is opened back up in spring. NC doesn't really have frozen water issues. Especially not during pool season.

a reply to: network dude

I believe boomer1947 pretty much covered it. I will add there is really no use running the pump for 24 hours. An already clean pool is fine with 10-12 hours of circulation. Allow it to move during daylight hours because of sunlight exposure while at night you can allow the pump to rest.

a reply to: network dude
Amp hr rated pump would require same amp hr battery. I'm guessing 4 35amp hr batteries exclusive to the pool pump, wouldn't put too much draw on a maybe 1500 watt panel array.
canada

I'm poor and go the harbor freight route.

a reply to: loveguy

that's the part I'm trying to wrap my head around. I don't want to over engineer it, but also if I'm putting money in it, I want it to be right. I think going with a more efficient pump motor might make a difference, but I have to understand the power requirements, then how to supply that plus a little for the eventual decline in power as the cells age.

I am hoping someone did just this at some point and can tell me all the things they wish they would have done differently. That's gold if you can find it. Thanks for the reply

a reply to: network dude
Customer reviews can help once determining the flow rate of sand filter (resistance) 15,000 gallons + ?gph pump rated at 5amp hr. 2" inch pipe - I think 5 ah is the sweet spot?

That's some hard figuring that needs paper and pencil- and a qualified electrician is the best resource available.

IBEW union guys are great to pull aside and ask electric equations if ya get the chance. You'll want a good one to inspect your work and make certain it is to code.

a reply to: network dude

Oh, I see. Yeah, I like the above idea of running it in the day.
My pool ran on a timer and wasn't constant on, you definitely don't need that.
You can run it for as little as 15 min, every 4 hours if you want to handle cleaning.
Full time on would be noticeable on your power bill on the "grid"
That setup with a battery bank would be nice.
Battery bank with smaller solar cells needed combined with timed runs would save a ton of cash on cells.
That product link looked cool, but haven't run comps on the motor though. There are some high efficiency dc brushless motors out there.
The filters typically have a pressure guage that builds up as it gets dirty, so psi isn't static on the diatomaceous filter setup, so you need a decent hp motor behind them, or good bypass valve.
good luck..post your setup when its done,

Dude if your happy with how your setup works now then all you have to do is look at the wattage your pump draws and make sure you supply that amount from your solar setup.

A solar regulator can be purchased off the shelf at reasonable prices to output your wattage requirements at the voltage your pump needs.

If you don’t mind it working only when the sunshines then you likely won’t need batteries. Pumps generally don’t need ‘clean’ power so as long as you supply the pump with electricity it won’t care about the source.

There should be a panel on the pump that has the wattage written on it, if you post the details I can probably find some links to equipment that will supply your juice.



a reply to: network dude

We live off batteries and big ones at that, in my opinion you won’t be running a 1500 Watt pump for long on previously suggested little 35 AH batteries at night, in fact they possibly wouldn't last a month and would be flat in a very short time each night. What is needed here is either real batteries 1000 or 2000 AH at either 24 or 48 Volts DC, then run an inverter to convert the DC in to appropriate AC power alternatively run a DC pump, which will offer greater efficiency as there are less conversions going on. You might also reduce the required power by using a smaller pump, however you then need to look at the flow of water through the filter when doing this.

Possibly the best rout is to buy or build a MPPT hot water regulator and drive a DC pump from this. That way no batteries are required and the pump will run when the sun is out. Most house panels are 250 to 500 Watt these days, and at a guess you will need about 5000 Watts of panels, to run your pump most days for 4 or 5 hours this should be long enough. You need to remember that as the heat increases the performance of your solar panels will decrease.

Second hand panels here in Aussie are very cheap, as a lot of folks have to rip out a previous instillation to install a new one, as lots of installers don’t leave much head room within the equipment spec due to costs etcetera. It does get more complicated if you start running different size panels and a clean slate is easier in lots of cases. Anyway best of luck.

Okay, so I kind of do this for a living (not intentionally, sort of a by product of other elements).

Just some straight math (and keep in mind, these numbers are optimum values.)

The typical residential solar panel produces about 300-400 watts.

A 1.5 HP pump draws about 11-12 amps at 110 volts. This equates to roughly 1,250 watts. Therefore, in a perfect world, you would need at least four (4) solar panels to support the load of a 1.5HP pump. Again, this is in a perfect world. Now let's talk about the real world (the one we live in). Depending on where you live, you won't have sunshine all day, every day. And, you won't have it at night either. You can easily find (on the net) factors to tell you what your solar energy is for your area. It will give you things like average days of sun, average length of day (throughout the year), and available energy based on attenuating factors such as particulates (smog, moisture, etc.) in the air.

Now let's talk about the solar panels themselves. A solar panel fresh out of the box will perform at maximum levels. However, as soon as that panel begins to collect dust and water spots, the performance % will degrade. A good nominal number to use as a rule of thumb is 50% of optimal performance. (yep, you read that right). What this translates into is, you will have to increase your solar panel count to account for this reduction in efficiency. So, just for illustration, let's say you increase your solar panel count by a factor of 2x. Now you have eight (8) panels required to run your pump.

The average solar panel size is roughly 3' x 5', or 15 SF. (8) x 15 SF = 120 SF (roughly a 10' x 12' area). This is the roof (or other) area you will need for the panels.

Now, we have to talk about running during 'off-hours', and this involves storage in the form of batteries. First, storage is expensive, so you're going to want to limit the amount of energy you are storing. Storage is also fairly high maintenance, and has fairly low MTBF numbers. So, it's expensive to buy, expensive to maintain, and it doesn't have a very long life. (short version).

Before we go too far down this storage path, we need to discuss some other things, inefficiencies. Nothing is 100% efficient. We already discussed inefficiencies of the solar panels, but there's more. Your electrical system will also have inefficiencies, and these inefficiencies jump significantly when storage is involved. Power can only be stored as direct current (DC), and your solar panels output DC, so no issues there. However, your pump uses AC current, and this means you will need an "inverter" to convert your stored DC power to AC current. The highest performing inverters in the market perform at a max of 90%, but this is the top of the line gear. Most residential systems will perform at values more like 80% efficiency. Thus, you have to add another 20% of capture to meet demand, if the load is fed from storage. In other words, even more solar panels. An additional 20% is essentially another (2) more panels.

Storage costs are about $1,000/kWh. Our load is 1,250 watts. If we assume 12 hours of sunlight and 12 hours of dark, then we're going to need roughly 15kWh of storage capacity to span 12 hours. Rough math = $15,000 for storage.

We don't do residential stuff, so I had to poke around a bit to see what a non-commercial / residential 4kW system would cost (so take this with a grain of salt). The solar panel system cost is roughly $17,000. And then there will be electrical work to connect everything together. The basic rough electrical work will be about $2,500, but to this you are also going to need to add one more component and this is a transfer switch to switch the load between battery and active. This will cost another $2,500+/- (most of the ones we do are much, much, larger).


System - 4kW system
Storage - 12 hours
Bottom line - $37,000

ETA - There's probably a couple other things in there I should have included. A voltage regulator and transformer will be required because the panels output a different voltage than the batteries require, and there's another power factor to consider there also though not as big as the inverter. Probably only around 3-5% reduction in efficiency (which we've already covered with the excess capacity of the added panels earlier). Figure another $400 bucks for the transformer.

Assumptions - Obviously, there are a number of assumptions here. They are essentially as follows:
- 12 hours of sun and 12 hours of dark
- 100% backup for off-hour operation (you can cut costs significantly by reducing this as much as possible).
- You don't live in Seattle! LOL! (where there is cloud cover for like 240 days per year).
- Your system can be installed in a fairly consolidated area. More spread out equals more $$ due to larger wire gauge to deal with DC voltage drop.
- Manual transfer switch. (If you want auto, double the transfer switch cost).

originally posted by: network dude
that's the part I'm trying to wrap my head around. I don't want to over engineer it, but also if I'm putting money in it, I want it to be right.

I think Flyingclaydisk gave really solid data of solar and it shows that it kinda sucks.

The one thing I will add is that you may be able to get a bidirectional counter, if you don't already have one, so that when your panels are pumping out power it runs backwards, offsetting the use from the grid by your pool system when they are not. This allows you to leave out the storage sub-system.

a reply to: Flyingclaydisk

in the OP, I linked a pump (DC motor) and a pump controller. It shows this connected straight to solar panels. I saw a youtube video of an installation like this and it just ran when the panels were powered. I would probably be fine with that, as long as it pumped a good bit of the day. The entire reason here is to help with the cost of running the pump over a long time. Anything over a few thousand bucks would be pointless.

The pump has good flow numbers and if it worked like it appears, it will be just fine. But I'd hate to waste time and money on this if it's pointless in the end.

I do appreciate all the knowledge from everyone.

a reply to: network dude
If the panels are not tracking the sun you won't have power for the pump for most of the day, without a storage system.

I think the formula used when designing a fixed solar panel system only uses 5 or 6 hours a day of usable sunlight with a ramp up for a couple of hours and a taper for a couple more. That leaves you with only 1 or 2 hours where you are getting "good" performance.

a reply to: network dude

If it works for you then I'd say go for it. However, just be aware, there is a whole lot of 'smoke & mirrors' in the solar power sector, particularly on the marketing side. Things are often not what they seem.

I wind up having to work with solar quite a bit in my job. I often have to do this because people are looking for what I call a "free lunch". (not suggesting this is you, just explaining). Unfortunately, there is no 'free lunch' with solar.

I am not anti-solar, nor pro-solar; it has its place, but is often wildly misunderstood. The point here is just that I get dragged into solar often times because of exaggerated marketing claims in the solar industry.

You know, I probably should have added something else for an explanation earlier, because I understand what you are trying to do, and I think you should do it if you can swing it. I also get not wanting to spend a fortune on the solution. So, hopefully this explanation will help a little. I'm going to throw the following explanation out here for yourself and any others who may be considering solar in the future (because it pretty much applies to any application of any size).

The bottom line with solar is this, based on my experience; solar can be a good investment over the long haul IF a person understands a couple key basic concepts:

1. The return on investment for solar is longer than most solar manufacturers want you to believe. And, the reason for this is because, if there's any question about the lifespan of their equipment, it can have a dramatic affect on the a customer's ROI. (This can make or break a sale for them, and they can't change the lifespan of their equipment, so they will often make the ROI numbers overly optimistic (i.e. shorter time)).

2. The ROI is longer than most customers think initially, so the longer time frame is often a big surprise to them. Consequently, the up-front capital seems very steep to a first time buyer. When the time element, and the up-front cost, element are combined together, the overall commitment (mentally) 'feels' a little overwhelming (understandably). To better understand the costs, customers have to amortize these costs over a longer period of time.

3. The critical "key" factor in the whole solar equation is to find equipment which will remain viable for a period of time which is longer than the return on investment. Seems like a no-brainer, but if the equipment fails and needs to be replaced before it has paid for itself then the buyer gained nothing.

Ten years ago, there were very few, if any, manufacturers out there who could make the ROI numbers work. They relied on government subsidies in order to demonstrate value (in real terms). Without the subsidies, up-front investment was often 2x or greater than the equipment lifespan, so full replacement would be required before the equipment was even paid for.

Only just recently has this changed, and as much as I hate to say why, but it is because off-shore sources have become the leading source for solar panels whereas these used to be US sourced (we won't discuss the trillions wasted by the US Govt under Obama subsidizing this industry). Now, investment and ROI on solar systems can be made profitable. So, this is a win for the consumer.

(and no, I am not in the solar business, nor do I want to be. And, the gear we work with is almost exclusively commercial / industrial grade equipment, so I really can't give you any specific manufacturers to consider for the residential sector).

Hope this helps.

If you can do simple electrical hook ups you could save allot of money. You pay more when you want ready made systems.

batteryhookup.com...

www.aliexpress.com... exp_id=fc048eab-7527-4870-be97-2b02b3d1d270-0&pdp_npi=4%40dis%21CAD%2141.70%2126.27%21%21%2129.79%21%21%402103244b16971750878881776e1731%2112000030840 716075%21sea%21CA%214482255984%21&curPageLogUid=VVCfkiO6QbNd

a reply to: XL5
Maybe I did the maths wrong but that battery would only run a 1.5hp motor for about an hour.

They cost $385 each so, if OP wanted to store enough energy from solar, they would need 18 or 19 of them, that's about 7K just in batteries, not to mention all the extra panels needed to charge them so they can run the pump during the 18 to 19 hours when the panels are not producing at peak efficiency.