@cengland0 For a long time, janitorial supply places and a few other outlets had three volt batteries that were the diameter of a D cell, and twice as long. Of course, what they really were was a thin cardboard tube with two ordinary D cells inside it. They pretty much vanished from the market about 20 years ago, although a few suppliers of flashlights for government contracts still coughed them up with some regularity. Yes, part of the reason for their existence was so that your friendly neighborhood federal government could spend more money on a thing that they could have bought more cheaply at any local store.
@thebigtverberg Why would the big manufacturers jump on something that would jeopardize their ability to sell tons and tons and tons of very profitable alkaline batteries that are guaranteed to go bad before people finish using them?
Removeable batteries for cell phones, so you can just have as many as you need to get through your day, and also not have to replace your whole phone every couple years just to get better battery life.
Wait, has that been done before??
Does your device require a C battery, but you don’t have one? Stick an AAAAAAAAAAAAAAAAAAAAAAAAA battery in it! Does it need a 9v battery? Use this AAAAAAAAAAAAAAAAAAAAAAAAA! Those annoying button batteries? This AAAAAAAAAAAAAAAAAAAAAAAAA will do the trick!
Idk, maybe with converter cases or something and it will magically do the job you need.