adam's notes

Battery Replacement

AC Adapters

  • To operate from building power, the laptop needs a power supply to convert the AC supply from the power company to the DC voltages used by the laptop’s components
    • power supply is provided as an external AC adapter
      • normally universal (or auto-switching)
      • can operate from any 110–240 VAC 50/60 Hz supply, though do check the label to confirm
      • rated for their power output (ranging from around 65–120 W)
      • connects to the laptop via a DC jack or a USB port

Info

  • Plugging a fixed-input 220–240 V adapter into a 110–120 V supply won’t cause any damage (though the laptop won’t work)
  • plugging a fixed-input 110–120 V adapter into a 220–240 V supply will likely cause damage

Battery Power

  • Laptop computers use removable, rechargeable Lithium ion (Li-ion) battery packs
    • typically available in 6-, 9-, or 12-cell versions
    • more cells providing for a longer charge
  • connector and battery-pack form factor are typically specific to the laptop vendor and to a range/model
  • Before inserting or removing the battery pack
    • turn the machine off and unplug it from the AC wall outlet
  • A portable battery is usually removed by releasing catches on the back or underside of the laptop
  • battery recharges when the laptop is connected to the AC adapter and is connected to power
  • When the laptop is in use, the battery is trickle charged
    • should come with a power management driver to ensure a proper charging regime and prevent repeated trickle charging from damaging it
  • Li-ion battery life is affected by being:
    • fully drained of charge
    • held continually at 100% charge
  • Balanced power charging stops trickle charging at 80%
  • Li-ion batteries are also sensitive to heat
  • if storing Li-ion battery:
    • reduce the charge to 40%
    • store at below 20ºC

Li-ion Batteries

  • hold less charge as they age
  • typically have a maximum usable life of around 2–3 years
  • If you charge a battery and the run time is substantially decreased,
    • you may need to purchase a new battery

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