Solar Panel

[Herb]

I would like to get a panel that will run my well pump and at separate times to keep my refrigerator cold. The pump is around 3/4 to 1 horse and runs off 220 volts and it is about 225 feet deep.  

Does anyone know how to figure the size of a panel I would need? I am looking for one to use when I am out of power due to a storm or something else that causes my electricity to go out for an extended time.


Thank you for your help,

Herb

[meackerman]

seems like you don't really want to run the pump directly off the solar panel(s).  You want the solar panels to trickle charge a battery that then the pump then runs off of.   Solar panel output can be pretty variable (clouds, time of day, etc), and produce no output at night.

[Mr_Mike]

More than you think.

Lets baseline the motor at 1HP and say it runs 1000 watts. Thus, you would need 1000 watts of panels if you has a perfect day, which doesn't exist. Panels are speced on 1000/watts per sq meter of sun light so that all panels are sold with equivalent ratings. The problem is you never see 1000 watts of sunlight. For instance, I have 7250 wqatts of panels and can only produce 5500 watts or so on a good day.

And, you still have the problem in inrush/start current which makes this not work anyway.

You are better served to charge a battery bank and then run the pump off of that. You would have to figure out how much sunlight you get and how long you need the pump to run per day.

I love solar. I think anyone who can make the math work should already have solar.

And after all that, I'd tell you to get a generator. Way more cost effective and convenient.

[Roly]

Don't forget the inverter must be rated for the starting current of the pump. As Mr Mike said look at a generator for the pump. Roly

[Snipe Hunter]

I think you have a good idea but the cost will probably far outweigh the benefit. A generator is more cost effective. I'd figure the wattage of a well pump and purchase a small Gen which could handle it plus your pressure switch. What I'd probably do is find a small 240v transfer switch which could handle those two circuits. So it would need to accommodate at least one 2 pole breaker (assuming it's a two wire pump) and a 1 pole breaker for the 110v pressure switch. Set the transfer switch on the exterior wall near the main panel connected to those two circuits. Then just wheel out the generator when you need it and plug it into the transfer switch. I'm "guessing" a 50 amp panel and a small generator...maybe 1000watts? Maybe less. I'm not sure what a well pump draws. I'm "guessing" between 700 and 1000 watts. It will be tough (if not impossible) to find a 220v generator in the 700 to 1000 watt range so you will probably have to up-size a bit. Since a pump isn't constantly running, you could also buy batteries which charge off of utility power and an inverter but batteries don't last for ever and they will eventually die in a power outage

Just look at your main panel and figure the amps of those two breakers and find a transfer switch that would handle it. It will look something like this:

50 amp outdoor transfer switch.

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Brain fart.
The pressure switch will be inline on the same circuit as the pump so it shouldn't need it's own breaker at the transfer switch. I'm pretty sure somebody sells an "interlock" or "Break before Make" breaker that could be set in a sub panel off the existing well pump breaker. I'd ask someone more knowledgeable than me if that's Kosher. That would be a lot cheaper than buying a transfer switch.

Keep in mind. This scenario is for a simple pump circuit, not for a pump with a control box.

[Roly]

Probably have to upsize generator to 2500-3500 watts to handle the startup current for the pump. Roly