Trekking without energy is difficult. I mean it's hard to preserve especially energy when you're deep in a cave, however. The cavelous mapalis maximus was designed with such benefiting features you will never have to worry about losing  energy stock. But how? Well it's quite simple, there is a wind up motor that can be used for charging phones and laptops. There's a set of conveniently spaced out  usb plug ins for this motor alongside multiple outlets, that way you would never have to stress over losing energy.