Idiom:

Recharge your battery ( full of energy )

Hit the book:
Randoseru
Sturdy
Ensemble
The latter
Ubiquitous
Iconic

Randoseru are the large, sturdy backpacks used by Japanese elementary school children to carry books and supplies while they commute to school. Maybe you've noticed them accompanying school kids depicted in anime or manga. Or maybe you've seen them on the backs of Japanese students as they commute to school in towns and cities across the country. These stiff leather backpacks are a traditional part of an elementary school kid's ensemble in Japan.