I used one of these converters....works great. Installed it hidden behind left lower cowl panel and attached a cigarette lighter socket outlet and ran it to the passenger side under the dash. Under $20 in Amazon...
https://www.amazon.com/KNACRO-Conver...120w+6v+to+12v
I was originally guided to it when I read this thread:
https://www.fordbarn.com/forum/showt...light=Inverter
Good luck!