Panel size? for pond pump 120v 60hz 460mA 20watts

Re: Panel size? for pond pump 120v 60hz 460mA 20watts

Your best bet--dig an 18"+ deep trench from your home (and GFI outlet) out to the pond and use the 120 VAC pump...

It will be the cheapest, most cost effective, and most reliable solution...

Otherwise, you are looking at, very roughly, spending about 10x your cost of electricity from your utility to buy solar panels, charge controller, batteries, inverter (if you want 120 VAC)...

Problem is that most DC pumps are not that reliable or that large in capacity. AC pumps are better, and you can get some nice well pumps that will run off of solar panels--but that is probably way overkill for this appication--and you have the decision if this needs to run 5 hours per day or 24 hours per day (which needs batteries)...

If this is a fun project to get your feet "wet" in solar--decide on what your pump (load) will be... AC or DC, wattage, hours per day, lift, etc...

Once you have those numbers, figuring out the rest is just a relatively straight forwards working backwards exercise.

Not knowing the load and power requirements--it is pretty difficult to give you a good idea of what the system would cost...

-Bill

Re: Panel size? for pond pump 120v 60hz 460mA 20watts

120 VAC at 60 Hz is the common North American utility power that comes out of your wall... Solar Panels and Batteries can only output DC voltage, and usually at a low voltage of 12 volts or so...

The small solar pump you have now is probably designed to operate with a solar panel. The motor may either be a brushed motor--which will not last real long (think of your electric drill motor with sparks coming out the brushes).

There are electronic motors that convert the DC into AC that last a pretty long time (the most common are DC powered fans used in computers).

I have not run across a DC electronically commutated motor used in a small solar powered water pump--there may be some--but I have not seen any myself.

So, if you want to do this small scale, find the DC pump you want to power, check the voltage and amperage requirement (best would be to use a Volt/Amp meter to measure the current under load). Then you would pick a solar panel that would best meet that load (using its own ratings for output voltage and current)...

You could do more--but that runs the cost and complexity up--something that you don't want.

Your basic cost will be--take the motor (say 12 volts x 2 amps = 24 watts) and look for a panel that has those specs... It will cost you around $5/watt *24W=$120 or more for the solar panel(s)...

There are some other issues--but it would be best to identify the DC motor/pump first--but basically, a solar PV panel is not a great source of regulated voltage--so it is easy sometimes to damage the loads if they are not designed for the wide range in voltage a solar panel can put out.

-Bill