Thanks for trying to help me out 
• The batteries should be ok. They are brand new IKEA rechargable batteries, which came directly from the charger. Homey even shows battery level of 63% for the other sensor that doesn’t show temperature or humidity (other one gives 100% so can’t be sure it is valid reading.
• Connectivity cannot be the issue. They were added to Homey when I was just few meters from the Homey Pro… and the room is full of IKEA zigbee lights that work as routers.
• I added them yesterday evening, and the data refresh frequency is ~10mins, so they should be working by now.
I haven’t tried re-adding. Should try that next 
