Is it possible to receive in a status callback the battery level/status. How?
In API4 you can see battery level after each downlink message in the confirmation OOB (Out of band) message.
In API5 the voltage is being sent in the daily heartbeat as well. Plus it can be amended to all messages if you wish.
In API6, you can append voltage to be sent to you in a heartbeat or in every message whose hex symbol is between 0x00 and 0x7F.
What are the battery levels for our devices?
For the SimplePack 2.0 RC1 and RC3:
2.0V-3.0V Full power
1.8V-2.0V Weaker transmission range
1.8V-0.0V Device stops working
For the SimplePack 2.0 RC2 and RC4
2.4V-3.0V Full power
2.3V-2.4V Weaker transmission range
2.3V-0.0V Device stops working
For the SimplePack 3.0 Plus RC1 and RC3