Happy birthday H. Have a good one.
Re power supply, I use a standard 12v power tank (Bunnings job years ago) with a seperate 20 amp swichmode charger that I bought from ebay (about $45) The charger switches to float mode once the battery voltage is high enough (approximately 14V) and I've encountered no problems with interference from the switch mode charger. I used that combination over 7 nights at Astrofest last year with absolutely no problems.