You are misunderstanding the problem. Older batteries are unable to provide the short-term burst in voltage required when the system CPU clocks up to handle inc

You are misunderstanding the problem. Older batteries are unable to provide the short-term burst in voltage required when the system CPU clocks up to handle increased load. This failure could (and did, I've experienced it) cause a shutdown, even at 100% battery charge. Turn the phone back on and it still says 100% battery charge. But the battery can't supply the peak voltage load, so the phone shuts off entirely. Myself, I prefer my phone to stay on, even if that means it runs a little slower.