We have had a similar thread here before.
There is a lot going on in the market. A device like the one Jens suggested is available in German supermarkets (e.g. Aldi) again and again for about 70 Euros. They have a 12V output that delivers 10A. That would be nice for a small PA.
I can’t say whether they switch off on reception due to the low power consumption of the KX2. Does anyone have any experience of this?
73 Armin