@martinhjelmare I made a PR. https://github.com/theolind/pymysensors/pull/80

I built all my sensors on NodeMCUs only because I had a large batch of them. My sensors use HLK to step down from AC mains current to 5V into Vin which I've had no problems with so far. Comms is via MQTT to Mosquito running on a Raspberry Pi alongside Home Assistant.

I'm experimenting now with a 600mAH 3,7V Lipo battery, charger and boost converter with deep-sleep just to see how far I can go.

Having said that if I would do it all over again I would go the Wemos/NRF way!

Yes, I'm using the persistence & pickle file. The PR fixes the problem. Just tested with latest HA dev branch. Thanks for the quick answer Martin.