Simple addition to my pump sprayer so now it is solar powered.

That moment that one of your ideas works, and works awesome ( rare). I added a valve from a tire to my pump sprayer, then I hooked up my car tire pump, with my homemade battery bank from laptop batteries. It pumps to 50 psi, and I don't have to pump the sprayer anymore for spraying my plants!!! This is part 1 of me making a foam device for air crete. I think i can put the battery bank in my back pack with the air pump will be portable !!

That is a brilliant idea.

I rarely use sprayers so i have some questions. If the sprayer is full, how many times does a person have to stop and pump before its empty? If its more than one, can you leave the pump on while you are spraying ?  That would be pretty cool.

It also seems that you are bypassing the portion that fails. When i say i use it rarely, it literally means i buy one, use it, then one or 2 years later when i have a use again i cant get it pressured up. I bet this trick allows it to work year after year.

As I thought about this, I realized I have another portable air tank.       I could fill that tank up to 50 psi drop in wheel barrow than fill up as needed without any safety concerns.    

Pressure blowoff valves are out there. Similar to what an air compressor has. Heck, i think there are caps for tire valves now that bleed off air if over inflated. I remember that being a cheat in nascar to maintain a set max airpressure from the heat expansion going 200 mph. Not sure if that tech has reached the marketplace. That would be in a range below 50 psi and as simple as drilling in a second air valve and adding the cap.

The question being whether you fill as needed or leave it running while you spray. If you refill, really dont need a blowoff. Maybe the sprayer already has one. Maybe there is leakage designed in the sprayer. Lots of stuff i dont know. Lol