I like the simplicity of the idea, but can't help thinking they are going off-track with solar and batteries. The users don't need added complexity, and they don't have money. What they have is manpower.
Depending on the natural resources available (sand, water, dirt, rocks, wood) and terrain (flat vs hills), I suspect this concept could be ramped up to a much larger scale using manpower. Consider a desert-like condition. Sand could be used as the weight. Instead of manually pulling a large weight to 'wind' the magneto, they could have something as simple as a fire brigade to transport the sand bucket-by-bucket up to a large container. The container, itself, could descend, creating the power (and raised back up after being emptied), or could empty into a verticle conveyor belt of smaller buckets, providing continuous downward drop. Simple machines (fulcrum-lever, Archimedes screw, slopes, wheelbarrows) could be used as appropriate. Anything could be used for the weight, and coordinated manpower could be used to increase the scale. A small output could be generated for extremely long periods, or large outputs for shorter time-frames.
To me, eliminating manpower by adding expenses and technology (batteries, solar panels, etc.) is exactly the wrong trade-off.