Some days ago I setup a simle RTL-SDR based monitoring station. Now after about 5 days of more or less constant monitoring I found one interesting thing:
One of my neighbours has a TOYOTA car. Its TPM sensors seem to transmit permanently. As you can see here, more or less regularily:
So I assume this car must have a pretty large battery, where this constant power consumption did not harm?!
The number of other detected TMP sensor is small, compared to the traffic on my road.