Ummm, not real sure what you mean by wirelessly. Use of something like an Astro meter or Watt meter, plugs inline between the pack and esc and reads out volts/amps/watts. Gives you real time readings.

And there are some units available that allow you to download the info to your computer after a flight, aka like a flight recorder.
That way you see how your system is performing over an extended period of time.