# Please Help Me Get Started



## joed (Mar 13, 2005)

Probably not.
A 5 HP 3 phase solar system will not be cheap.


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## Deja-vue (Mar 24, 2013)

Takes about 15-18 250W Solar panels, a good Inverter[SMA] don't know where you would mount the Panels, and Labor is involved.
Without knowing all of this, I'd guess about $17K would cover parts and Labor. YMMV, of course.
ROI in 7-8 years, probably.


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## seharper (Mar 17, 2020)

The first law of alternative power is _conserve first_. In utility supplied mains, they don't care - they just throw inefficient hardware at the job and declare victory. So I would re-assess the pump system and see if efficiencies can be had there. If a motor half the size will do the job, you just cut system cost in half. Or if the motor could be driven by a VFD at lower power draw, that'd be great too. 

Running _direct_ off solar is challenging because solar panels have variable output depending on their angle to the sun and how clean they are. So either you laughably oversize the system and have power to burn in midday, or you have weak pumps in morning and evening. 

So if you have a 4000W motor and an optimistic 2:1 solar panel sizing, that's 8000W. But on cloudy or stormy days that energy just won't be there and the pump will not run well or at all, depending on the protective circuits. Probably best would be to have a VFD of some kind designed to drive the motor as fast as it is able given the power available. That would also assure a soft start. 

If you want to run it on battery, your fountain currently uses 70 KWH per day. If you had a 1 day battery supply, that is roughly the power pack of a Tesla Model S. Even "slightly used Tesla modules off eBay" would be $15,000 of battery. It could be somewhat less if you didn't mind the battery going flat and the fountain shutting down during several-day sequences of poor solarization. 

Possibly use a much smaller battery, and in poor days fall back to a schedule so it runs during commute or *runs on motion sensor when a car approaches LOL*. After all, why run it if no one is there to see it? Wow, that really is the best plan, now that I think of it. 

To fill a 70 KWH per day battery, an optimistic rate I've hear is to assume 4 hours/day of _useful_ performance from panels. So a 70 KWH battery would need 17KW of panel, or about 4 times what Deja-Vue said.



If all you want is to offset the electric bill, then you are "using the grid as a battery" and talking about a _grid tie_ solar system, and "70 KWH/day" is simply your production target. I doubt they will give you "net metering" on a commercial account, so you would have to do a business deal to get the power company to buy your generated power. So we're really into a business venture at that point. It hardly makes a difference whether the solar is at the fountain, or in a more practical and productive location, such as Antelope Valley, CA.


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