MacBook Air battery keeps charging after 100%

[yonz1138]

Hi guys, thanks in advance for any ideas.

Just hooked a MacBook Air M2 to an external display through Thunderbolt 3. The monitor´s Thunderbolt happens to charge the MacBook Air as well, but after getting to 100% charge, the macOS upper right battery icon keeps displaying a ray (which I understand means "charging") instead of a plug, but when I click the icon the menu it says that battery is fully charged and power source comes from power supply.

Even more strange, if I go to "System Information" within Settings of the Mac, in the "Power" section it says it IS charging.

Is this behaviour normal? Can the external display power delivery be faulty and keep providing charge even though battery is fully charged? Can the MacBook´s battery have the risk of "overcharging" (and igniting)? This is driving me nuts and I don´t find any info over the Internet. Thanks in advance!

 

[Bigwaff]

but when I click the icon the menu it says that battery is fully charged and power source comes from power supply.

While laptop is attached to Thunderbolt cable, it drawing power from the TB cable. When charging, some power will charge battery and some power will run computer. When battery fully charged, computer draw power from TB cable, not battery, and battery will stay fully charged (most likely pull trickle charge). This normal. The macOS will manage battery charge/discharge. Unless your laptop is getting too hot to touch, no worries.

 

[yonz1138]

While laptop is attached to Thunderbolt cable, it drawing power from the TB cable. When charging, some power will charge battery and some power will run computer. When battery fully charged, computer draw power from TB cable, not battery, and battery will stay fully charged (most likely pull trickle charge). This normal. The macOS will manage battery charge/discharge. Unless your laptop is getting too hot to touch, no worries.

Thanks a lot @Bigwaff for your reply and explanation, very instructive 😊 Yet, what I find weird and makes me worry is that even though the system said that battery was fully charged, inside “System information” it stated that it was indeed charging.

After I wrote the original post I unplugged the MacBook from the Thunderbolt cable, updated macOS and restarted a few times as usual. Plugged the Thunderbolt back and this time, voilá, “System information” showed that Mac was not charging as the battery icon menu (on the top right corner) said, as before, that battery was fully charged. To sum up, the exact same as before but this time “System info” showed what I expected, and that as battery was fully charged it wasn’t charging anymore.

Don’t know if this thing is a software issue or a hardware issue from the MacBook or the external display…