> They were slowing the phones to preserve battery life, giving the appearance of longer useful battery lifespan. I don't like this explanation because the ter

> They were slowing the phones to preserve battery life, giving the appearance of longer useful battery lifespan. I don't like this explanation because the term "life" is loaded and could mean a few different things. The issue wasn't with the battery's capacity, ability to hold a charge, and not really how long the phone could run before needing to be charged. The issue was that the battery's C-rate was too low for the load. The C-rate is the rate at which a battery can safely be charged or discharged without damaging it. When you exceed the C-rate you damage the battery and increase it's internal resistance. As a battery's internal resistance increases, the amount of current it can supply decreases. When the amount of current a battery can supply drops below what the load draws, the voltage drops. This voltage drop would cause what Apple described as "unexpected shutdown". Apple throttled the devices to reduce their maximum current draw, not because the batteries were discharging too quickly but because they were drawing too much current which was further damaging the battery AND causing low voltage drops AND unexpected shutdowns. It's not clear if the batteries were out underspec, of spec from the supplier, or had an issue which caused them to prematurely degrade. In any cause, they were defective and Apple manipulated the defective devices to hide the issue and when called out offered people discounts rather than issue a recall.