My solar panel is a 100W solar panel and it reaches a charging rate of 90W+. At this rate, I get more energy stored in my power bank than I really need for the rainwater pump. Since I run the water pump once a week for 30 minutes.
Either I would add more rain barrels by daisy chaining them so that I have more rainwater collected or I need to find a better use for the extra solar energy that I am collecting.