I went this way for when on shore power or having the generator running
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
and this way with the standard 12 V chargers
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
One of these is in the bedroom to power my C-Pap unit when on battery, and one is near the table to either be used for charging devices, or, with a small inverter, to power my laptop.