The questions might sound silly at first sight, but let me share my observations so far:

  • I'm in the U.S. right now where I use the charger I got from IT and I see that my MPB charges slowly. It says the battery is 51% full and will take another ~16 hours to fully charge
  • In my workplace I experience that too the charging stops around 80% and does not matter which plug I use
  • In the hotel with the same charger the same MBP charges two-three times faster and does not stop at 80%
  • home, which is Hungary with 240V electricity grid, reaching the fully charged state takes 2-3 hours (does not matter if I recompile my app in every other minute) and never stops at 80%)
  • I brought the charger came with MBP and the phenomenon is the same

Since I'm not an electricity engineer I don't know whether voltage matters in charging or not. In the U.S. there is 120v, but in EU we use 240V. Differences in Amper, I'm not aware of. In the EU, we use 20A or more fuses.

Is it possible the difference I experience is due to something default Apple magic in MBP?

  • Are you controlling for the temperature of the Mac and doing the timings when it’s powered off or sleeping?
    – bmike
    Commented May 20, 2019 at 22:06
  • @bmike: Nope, I don't have anything like that. Commented May 20, 2019 at 22:07

1 Answer 1


There's no "magic" involved in charging.

The standard Apple charger delivers the same voltage and amps to the laptop when used on a 120V grid as when used on a 230V grid. So the type of grid should not matter.

20A fuses are definitely not common in all of the EU, it is much more common to have 10A fuses for lights and other outlets in normal homes, and 16A or more for kitchen appliances, etc. However, this doesn't really make any difference for charging a laptop. Even 10 amps at 120 volts is 1200 watts - which is way more than what is needed to charge any Apple laptop, as Apple's largest laptop charger is a 87 watt charger.

There's also no geographical components to charging. It is not so that the Apple charger knows that it is in Hungary and charges quickly, and knows that it is in the US and charges slowly. There's no such provision in any of Apple's chargers.

The most likely cause of your problem is that you're simply not using Apple chargers or not using the correct Apple charger. When you're in the US, you might be using a less-than-recommmended watts charger - or a knock-off charger. This would explain why it charges slowly.

  • Thanks for the response. I'll get another charger. Commented May 20, 2019 at 22:06

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