I'm not sure this is a realistic use case to try and support. A 10 year old android phone likely has a battery life measured in 10s of minutes, and really isn't something we need to worry about.

You get the guy at the mall to swap in a new battery for $50 in most parts of the world. Its cheaper to do that every few years than buy a new phone, and I have several family members who refuse to upgrade on principle, because modern phones grew too large for their hands/pockets