[bdash]

Batteries not getting lighter with reduced charge is relevant in that it's not uncommon to trade reduced range for increased payload by carrying less gas. With batteries having a fixed weight, you don't have the ability to make that trade-off in an electric aircraft.

[AWildC182]

These battery systems are usually designed to be modular so you can add/remove/quickly swap them. Think server rack like trays full of battery packs that you can chose to partially or fully populate scattered around the airframe

[outworlder]

Eh... are you going to be able to do that without an A&P? You can only do that at the start of your trip (unless you want them shipped to your destination, I guess).