All phones have hard coded battery management, but where to set the "100%" level, which trades off the longevity vs battery capacity is fixed, and not user adju

All phones have hard coded battery management, but where to set the "100%" level, which trades off the longevity vs battery capacity is fixed, and not user adjustable. As a phone manufacturer, they want to advertise long battery life, so push more towards that than I would like, and can't decide based on context (e.g. staying home vs travel). There is literally no reason for this not to be a user settable parameter on all devices, other than that there is no incentive for manufacturers to do so. Most electric cars however, do have the ability to set this. However, because phones are locked down for security reasons, there is no way to make these software adjustable with an app, unless you root the device. Hence the need for a hardware solution.