All rechargeable batteries are consumable components that
become less effective as they get older-and their age isn't
determined only by time. A battery's lifespan depends on its
chemical age, which is affected by factors such as its
temperature history and charging pattern. As your device's
battery ages chemically, its charging capacity gets smaller.
Sage advice: Don't get caught with your battery down. Don't
be out of juice when you need it most.
Maximizing Battery Life and Lifespan
https://www.apple.com/batteries/maximizing-performance/
Update to the latest software.
Apple software updates often include advanced energy-saving
technologies, so always make sure your device is using the
latest version of iOS, macOS, or watchOS.
Avoid extreme ambient temperatures.
Your device is designed to perform well in a wide range of
ambient temperatures, with 62°F to 72°F (16° to 22°C) as
the ideal comfort zone. It's especially important to avoid
exposing your device to ambient temperatures higher than
95°F (35°C), which can permanently damage battery capacity.
That is, your battery won't power your device as long on a
given charge.
Charging the device in high ambient temperatures can damage
it further. Software may limit charging above 80% when the
recommended battery temperatures are exceeded. Even storing
a battery in a hot environment can damage it irreversibly.
When using your device in a very cold environment, you may
notice a decrease in battery life, but this condition is
temporary. Once the battery's temperature returns to its
normal operating range, its performance will return to
normal as well.
Here are some ways to safely charge older phones:
Never cover your phone while charging. Lithium-ion batteries
can overheat if covered with a blanket or clothing and if it
gets too hot, they can explode. Never charge your phone in
bed or under your pillow.
Don't charge your device with cheap cables, docking stations
or adapters. Always use official or certified chargers and
cables. Knock-off brands have had overheating problems in
the past.
Never use cables or charging accessories that are damaged.
It only takes a small spark to start a fire.
Stop using your phone while it's charging. Using your phone
while charging can rapidly increase the temperature, putting
strain on your battery, screen and processor.
Caring for your Surface battery
https://support.microsoft.com/en-us/surface/caring-for-your-surface-battery-9ccdfa7b-d074-f629-425c-1c090ac66bed
About battery health management in Mac notebooks
https://support.apple.com/en-us/HT211094
System Preferences > Battery
iPhone Battery and Performance
https://support.apple.com/en-us/HT208387
Settings > Battery > Battery Health
Maximizing Battery Life and Lifespan
https://www.apple.com/batteries/maximizing-performance/
Charge and maintain your iPhone battery
https://support.apple.com/en-us/105105
For most customers, the battery in your iPhone should last
the whole day. You can charge your iPhone every night even if
the battery isn't fully depleted.
iPhone automatically stops charging when the battery is fully
charged, so it's safe to keep your iPhone connected to a
charger overnight. Charging resumes automatically if your
battery level drops below 95 percent.
When possible, unplug your iPhone after it has fully charged.
By default, your iPhone uses Optimized Battery Charging. To
improve your battery's lifespan, Optimized Battery Charging
reduces the time that your iPhone spends fully charged. It
fully charges your iPhone just in time for you to use it.
sam.wormley@icloud.com