@Jigzy
Probably perfectly doable for everyone, via QueenBeeconWidget. although, as it's reading data via i2cget, it couldn't update itself constantly - something like 1 auto update per minute (+ on touch) should be ok.

@Jordi
I have no idea, as I don't own N9(50), so NFC if something like ic2tool exists there, what type of charging chip it use, how to handle notifications (are there any?) etc, etc.

So, it's definitely a task for someone owning devices in question, already.

/Estel