I decided I'm getting one built in. I have a skyecho, was at Parkes on the weekend. I thought I turned it off after landing. Anyway, a normal USB-C cable wouldn't charge it in flight, only the one supplied which I didn't have with me. For the extra expense, I don't want to be fiddling. It's going to be for the long term since I expect rule changes to be made in the Sydney Basin and eventually an ADSB requirement.