Then, magically, when I was reading a blog which had Google Ads in it, I saw an Ad on the right which showed "Hand-pump based rechargeable batteries" and I was like "That's so cool! I want to buy it", then realized how Google's algorithm was influencing me to buy things that I didn't even know existed.
Somehow Google was able to make out that I'm interested in things that are hand-powered. I'd like to think it was random, but I know that's not the case.