This website sells solar generators (ie., basically just big battery with outlets, charged by solar panels).  You have to buy the generator and panels separately, or as a bundle.  Not cheap, but essential for off grid living.

https://www.jackery.com/products/explorer-2000-pro-portable-power-station

Note that these are WAY quieter than using a gas or diesel generator (but not as powerful), or even gas inverters, which will be important for not giving away your position, or drawing attention.

I've thought about solar, but it seems as though I'd need a large number of panels to just get a modest amount of power.  So I've opted for propane tanks and a dual fuel generator (propane & gas).  Propane is good because it stores forever (unlike gas) and if the gasoline supply gets disrupted, you still have your propane.  I have a propane hot water heater (Joolca), a small propane cooktop, and a vent-free propane heater (I figured we'd huddle in a small room).

Big concern I have is that the lower level of my house that requres a sump pump; otherwise it would flood.  And a sump pump would drain a battery very quickly.  I don't think I could keep up with the power needs even with a dozen solar panels.

In any case, I'm not a big fan of the packaged "power station" setups because they're overprice.  If you get some good batteries, the panels, a solar charger, and an inverter, you can get the setup for a lot cheaper.  It's really not that hard to put together.  I don't have one of these right now because it would be very expensive.  Various 12V appliances are more efficient than using an inverter, but those are also rather expensive.

We installed french drains around two sides of our house because during heavy rains the basement would flood. Not badly flood, just a thin layer of water in certain areas. The french drain was connected to a pipe that drained though the yard and out to the street. The foundation of the old house in those areas had become quite porous. The drains worked great - there was no more water incursion. But you might have too much water for that type of drain.

How many thousands of gallons of water are you pumping? Because I'm familiar with pumps, and I didn't think they sucked that much power. I use a 120V "utility pump" connected to a garden hose to pump out my pond (to water my trees each year), etc.

They make 12V pumps, which would be easier to run off-grid and probably more efficient.

Here is the one I have:

https://www.amazon.com/gp/product/B000X05G1A/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B000X05G1A&linkCode=as2&tag=httpwwwchanco-20 />

Unless you have a *lot* of water, you're not going to be running the thing that long. And to state the obvious, it only consumes power while it's running. I guess you could estimate the square footage of your basement, multiply by the depth of water, to get an estimate on how many gallons. These pumps do up to 1800 gallons per hour. So you could estimate their run-time somewhat.