Laptop charging data points

I’ve wondered for a long time about the best way to charge my Mac laptops. As you probably know, there is a lot of conflicting opinion on this topic. :slightly_smiling_face:

So last night I watched the wattage in use as my M1 MacBook Air battery charged to 100% while observing with a “Kill A Watt” Energy Usage Monitor in the circuit.

  • from 49% battery to 94% the wattage used was a pretty steady 31.4W
  • at 94% battery, usage had dropped to 16.4W
  • at 98%, it dropped further to 9.7W
  • at 100% battery, the charger was using less than 4W
  • while doing various tasks on the MBA with the battery at 100%, the wattage varied up to 10W as if current was being pulled directly from the house circuit as needed
  • when I put the MBA to sleep, wattage dropped to less than 2W
  • after being shut down, wattage dropped to 0.0W as measured on the Kill A Watt
  • So it seems there are some smarts built into Apple’s battery and charger system. And you are probably okay leaving it plugged in even after the battery reaches 100%.

The fact remains that now the battery is holding at a full charge which is not supposed to be good for it.

I think I’ll return to my practice of making an effort when I can to begin charging at 40% battery level and discontinuing at 80%. My past experience with a swollen battery urges me to caution.

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I keep my MBA plugged in 90% of the time and use the ALDENTE app to manage my battery.

AppHouseKitchen – Mac Software for the Gourmet

Thanks for the reminder about this app. Their website seems much improved. Keep us posted if you would about your experience with the app over the long term. Getting past the three-year mark (1000 battery cycles) with no battery swelling would be a good sign.