Pumping water without batteries in emergency situations

First off pv panels are current sources and inverters are looking for voltage source like a battery. So connecting the panels directly to an inverter will not work.

Now you can run a DC pump directly from the panels provided the pump is rated for the output current and voltage the panels system produces.

I have a DC fan in my shed that is connected directly to a small panel and it runs at different speeds depending on the amount of sun hitting it.

If you are trying to use solar to run a water pump during an emergency you will need to build a solar/battery system which includes batteries and charger along with the panels and inverter. Depending on what the pump requires to run it will probably be cheaper to just get a small generator to run it to some type of tank and then send the water to the use point by gravity.

Thank you for the reply! While I understand that the panels are a current devices like a semi conductor but they also have voltage. For instance a 48v MPPT charge controller will not function unless enough panels are placed in series to exceed its output voltage by a margin. If I put a DMM on the panels output it shows a increase of voltage as i add each panel. This voltage is still present with current flowing. Would this not meet the input requirements of the inverter if configured to them? I know your answer is no but i dont understand why... Is it Because the current is determined by the panels not the load of the inverter even if they are matched?

PV panels cannot produce consistent power. The sun is always fading in and out - our eyes cant see it. And Panels cannot produce surges of current needed to start an AC pump.

Sadly, a generator is a better option for short term emergencies.

Basically the panels rarely provide a constant current output to a load which why that load need to be variable speed. Fans and DC pumps work with panels but an AC load connected to an inverter will not be able to run if the panel current & voltage changes. You need a constant voltage source like a battery to feed the inverter.

Thank you for the reply suneagle!

Ok I found this. "DC-DC Boost Converter with Constant Output Voltage for Grid Connected Photovoltaic Application System " https://core.ac.uk/download/pdf/12342408.pdf

And this ... https://www.ebay.com/itm/1500W-DC-DC...oAAOSwRWdfROTu

Assuming i can get max power out of it 20 amps at 60v, Its very marginal with inverter losses. However I was running my pump and household needs off a 1500 watt inverter for a while till I upgraded with no problem. Lighting desktop and on demand propane water heater all on at same time as pump and inverter didnt choke so... Maybe that grundfos SQ is pulling under 10a 120... Have to get a clamp on amp meter on it. The "soft start" claims start amps same as run amps.

Hey what can I say it how i get my kicks. It a relatively inexpensive way to have fun.

That item may work. But it is your money and time to spend on experiments.

Let us know how it works out for you.