Portable charger.
Very simple construction.
Easy to assemble and transport.
Simple way to increase productivity up to approximately n times without using expensive additional photovoltaic elements.
n= (d-1 )/ w.
where:
d = diameter of parabolic reflector,
w = width of photovoltaic element

Parts:
Rotating platform with mechanical or electrical gear to follow the sun's movement.
Chain of flat mirrors.  In a working position they form a parabolic reflector.
Semi-ring holder used for fixing top side of chain of mirrors and top side of a chain of photovoltaic elements.
Chain of photovoltaic element for converting sunlight to electricity.
Every mirror on top and bottom have rods.
Rotating platform and semi-ring holder have holes for mirror rods (or folding rack version 2 in picture 2).
Different size chargers can be produced for different purposes.

Can be used in various cases :
For travel.
Temporary use to compensate power lose due damaged equipment.
Additional energy for seasonal use when solar power is effective.
For military or scientific expeditions.
For poor countries/communities.