Switch gives a low battery icon even though it's charged, and will sometimes crash and make a SUPER high pitched ringing noise while overclocking.

[Pyoro_]

title, one time, it started doing this while I was playing a game without overclocking, is my switch faulty?

 

[BigOnYa]

You can check the health of your battery by booting into Hekate, goto "Console Info" / "Tools" / "Battery" and it will show you this screen as shown below. To find out your battery's health, divide "Capacity design" by "Capacity full" and that is the percentage of life left on the battery. Example below is 4667/4670= 0.99, meaning 99% life left. If it is low, I would replace the battery. Not sure about your other issues though, sorry.

 

[thesjaakspoiler]

A high pitched noise usually comes from the coils in the power circuit.
That might indeed be some battery problem (too high resistance or too much current flowing to it).
Batteries at the end of their lifetime do behave like you described.
The report incorrect voltages and the charge can suddenly drop significantly.

 

[TomSwitch]

Seven years old is a ripe old age for an electronic gadget.

 

[ChanseyIsTheBest]

title, one time, it started doing this while I was playing a game without overclocking, is my switch faulty?

I'm confused are you overclocking or not the title says you are but your post says you aren't.