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/   
     
     
 
    sam.wormley@icloud.com