allot, fill
充 centers on making something full or complete: filling a container, meeting a need, or allotting enough to reach fullness.
充 is thought to combine 亠 (a lid or cover) with 允, which may contribute the sound and the idea of fullness or completion. The exact historical development is uncertain.
The top 亠 is like a lid, and the bottom 允 looks like a container being filled. Picture a lid placed on a full container: 充 means to fill or allot until full.
For ジュウ, imagine filling a container with juice: juice -> ジュウ, and the container is filled to the brim.
charging (electrically)
fullness; completeness; perfection; substantiality
replenishment; supplementation; supplement; replacement; refilling
expansion
filling (up); replenishing; filling in (a tooth); loading (a gun with ammunition, a camera with film, etc.); packing; plugging
to assign; to set aside
being filled with; being full of; permeation
sufficiency
allocation; appropriation
congestion (with blood); hyperemia; hyperaemia
inductive charging
person who is preoccupied with appearing popular
trickle charge; trickle charging; TC
full charge (battery, condenser)
being poor but satisfied; not desiring a higher salary
hormone replacement therapy
portable battery charger; power bank
person who is satisfied with their real (offline) life; normie
wireless charging
single charge (esp. in electric vehicles)