I have a Galaxy S9+ (with "fast charging"), which requires a USB-C charger. I also have a MacBook Pro with a USB-C charger.

I am curious whether I can (safely) charge my Galaxy S9+ with my MacBook charger. The phone shows that it is charging, and very fast actually.

However, I am not sure whether the charger has too much power and would negatively impact the battery on a short time (perhaps get too hot or even cause physical damage/explode) or long-term (decreased battery health).

  • 1
    Just a thought, you might want to ask this in a forum for Samsung phones... Commented Sep 7, 2018 at 23:57
  • If you don't get an answer here, try asking on Android.SE
    – airsquared
    Commented Sep 8, 2018 at 0:06
  • @SteveChambers the question is related to Mac.
    – Ruskes
    Commented Sep 8, 2018 at 0:38

1 Answer 1


All devices (Phones) are 5 Volt technology.

How fast it charges depends on....

Can the charger provide the power the battery is asking for.

Battery is a SMART battery type (it has a chip build in) so it will regulate the charging process safely.

  • Not all devices are 5 volts. Part of the reason for the popularity for USB-C is that it can provide more than 5 volts. Common voltages from USB-C power supplies are 5V, 9V, 15V, and 20V. These are nominal voltages and some power supplies will output something like 5.2V or 20.2V to account for voltage drop across the wire. Devices that charge from USB-C are "smart", as are USB-C chargers, they will negotiate which voltage will be used and the device will manage the charge applied to its battery. So long as both the charger and device comply with the USB-PD spec connecting them will be safe
    – MacGuffin
    Commented Dec 17, 2020 at 0:49

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