A single AA battery. That’s all that is needed to power the most basic phone dubbed SpareOne Plus. As you can tell by the name, this one is intended to be a backup phone only to be used in case of emergency (it was originally designed for first responders). Its best feature is that it can sit on a shelf for 15 years and be ready when you need it. Modern phones with their lithium batteries can’t match such endurance – the self discharge rate can be as high as 2% per month, meaning lithium batteries lose charge even if the device is completely powered down. And they are, of course,...
Source: https://www.gsmarena.com/flashback_that_phone_runs_on_what-news-47607.php
