I bought a huge rolling plastic tool box. And it is too small.
This has to carry equipment and tools to fly electric, glow and gas planes and helicopters.
I have a lawn mower battery in it so I have to charge it maybe twice each season.

Many people don't like power panels, I think it's convenient. You don't need to worry about another battery to charge.

The tools you need will depend on what you fly. A set of allen wrenches, glow plug wrench, crescent wrench, screw drivers, exacto knife,
Glue, variety of pliers, screws, spare plugs, wheel collars, spare servo, maybe a spare rx battery, clear tape to repair small holes in the covering, fuel pump(s), starter, and of course the item you left at home (always something )