eli5: why can iphones be so quick to charge to 80% and then slow down, whilst apple watch charges quickly and doesn’t havw to slow down
In: 3
Software. The iPhone and the Apple watch have battery management systems. These are what actually controls how the battery is charged. What you plug into the wall is just a power converter.
Apple has programmed that behavior. If the iPhone and watch use lithium batteries with different chemistry this changes their charging profile and best practices to maintain battery health. Normally with lithium batteries they don’t like being fully charged or fully discharged. Chargers will slow down the charge rate as they fill up to reduce heat and maintain battery health. I believe Apple does have some restrictions on charging the watch and EarPods as I get notifications saying that charging is scheduled to complete some time in the morning. The device only charges to ~80% and then waits until just before you need the device to finish charging.
You can see this with EVs. Basic rule of thumb is 20-80. Don’t let the battery fall below 20% and don’t charge above 80% for day to day use. For road trips you can safely charge to 100% and use fast chargers as the battery is designed to handle the extra stress in moderation.
However again specific battery chemistries can change this behavior. In new base Model 3’s from Tesla they have changed the battery chemistry. Now those batteries are fine being constantly charged to 100%. The trade-off was less energy density which is overcome by adding a few more cells. It also might charge a bit slower or something.
Latest Answers