Thinkpad 13 Charger

Does the charger have a built-in capability to detect when the laptop reached 100% and stop charging the laptop?

Background story:
I have TP13 for a few days now and I've been checking the battery health on HWmonitor.
Before today I didn't charge it to the maximum and it didn't have any battery wear before.
But just now, I left it to charge for a few hours and I estimate that I unplugged it 30mins after it was fully charged.
Now I found out that it has 1% battery wear which surprises because I read that chargers and laptops are smarter now and will stop charging to prevent any damages to the lithium battery.
It also saddens me because it's a new laptop.

[I found out about the custom battery threshold in Lenovo setting after this incident. But would still like to know if the charger has the capability]

 

Yes, it stops charging the battery once it has reached 100%.

 

general question - i just bought a thinkpad 13 - the power button on the unit does not light up when i switch on the laptop - is that by design (i.e. no led light under the power button)?