If you don’t mind tinkering you could make one yourself (esp8266+pir+lightsensor) and it costs a fraction of what a hue or aeotec sensor costs. More on that here
Anyways going back to topic, I’m also using a Hue sensor and Homey v2. The Hue sensor reports relatively often but not real-time. This would indeed drain the battery. The interval seems like approximately every 5 minutes. An example graph with a day’s worth of sensor readings.
Blue = Phillips Hue Motion sensor, Yellow = esp8266 + lightsensor
