Is there a way give a sub class charges?

Is there a way give a sub class, charges in one of its ability

You can, under "Racial Trait" > "Action" > then "Limited Use".

What Sigvard said, except "Feature" instead of racial trait. Also you have to create and save the action before you can set the use limit.

Whoops... for some reason I had subrace not subclass in my head as I was typing. 

Unfortunately, if you want those “charges” to work for multiple spells I’m not sure it will. Hopefully I’m wrong and someone can educate us both.