Running everything through an inverter can waste a lot of battery power depending on just how big or small the load is.
For devices like cellphones, tablets, laptops and any other low power device you are better off buying power supplies/chargers which can take the 12V directly from the battery and convert that to 5V (USB items) or 18V-19V for laptops.
Much more efficient than charging cellphones, tablets and laptops from 120V inverter.
For 5V USB charging, you simply use a cig lighter plug in USB charger, like this.
If you do not have a 12V cig lighter power port in your RV, they can be added fairly easily.
