Help: Pump water into barrel for cheap? (and off-grid)
The goal: pump water from a small stream into a rain barrel (or IBC tote) in a location with no electricity. It's for having water available for watering fruit trees and doesn't need to pump much volume (even 100 gal/week would be great). It does have to do it while I'm not around though and I'd like to do it as cheaply as possible.
My idea is to make a small diaphragm pump out of pvc (for the housing) and some rubber (for the diaphragm) and a couple check valves. My inspiration is this guy's pump. I could drive it with a small DC motor powered by a solar panel. Maybe install a float switch that turns it off if the barrel gets full.
Any other ideas on making a diaphragm pump using cheap or found parts?
I've never done anything with solar and would appreciate any advice on components. What needs to go between the panel and the motor, if anything? I've heard talk of a "controller" but have no idea what it is or what I'd need... Also a goal is to design using as low power motors as possible so that I don't have to spend much on panels.
I've also played around with the idea of something wind powered, like this thing (but cruder, presumably). And had this other crazy idea to make a bellows-style pump for a windmill using a toilet plunger.
Anyway, any thoughts and ideas are appreciated!