how do i charge my airpods case can i charge it without my airpods in the case

You may charge your case with or without the AirPods inside.

Charge your AirPods with charging case and learn about battery life - Apple Support

Is this also true with the new wireless case?

Mine charges perfectly well whilst the AirPods are inside, but when empty, although all the lights are on and the case warms up, the battery level never increases.