After an initial charging mains, the lamp has given me light for a week for a use of 2/3 hours a night during the trek. Then 10 minutes of cranking enough each day. Really waterproof and submersible, she is not afraid of falling. The powerful full beam gives a light jet that carries far enough. Only downside, the axis holding the handle to the crank seems fragile, so it is necessary to turn it gently, avoid turning like crazy.