When the Parent Unit is removed from the AC Adaptor and in Video + Audio Mode the rechargeable batteries will last approx. 4.5 hrs:
When the Parent Unit has the video screen on constantly as with all cordless devices this will naturally drain the re-chargeable batteries when it is not plugged into the AC Adaptor
In addition to this the amount of noise in each home is different, therefore as the Parent Unit is constantly transmitting background noises, music etc. these will also drain the battery power in this unit
When the Parent Unit is removed from AC Adaptor and in Screen Save + Audio Mode the rechargeable batteries will last approx. 9 hrs:
It is recommended that should you wish to use the Parent Unit in Video Mode (out of power save mode) for long periods of time whilst also using continuous sound transmission that you keep the Parent Unit plugged into the AC Adaptor
This is indicative of any product (such as your mobile phone) that constantly streams information, video etc. This function uses more power that when any unit is standby/power save mode.