One problem with solar systems is the need for high-efficiency DC-DC converters. For example, if lead-acid 12V storage batteries are used, then the user is faced with the problem of down converting that 12V source to many devices that use 3V, 5V, 9V, etc.
One way I thought of to side step this problem would be to use battery cells aggregations, instead of single large batteries.
For example, lead-acid cells provide 2V and Ni-Cad cells provide 1.2V. Therefore, you could combine 2 lead acid cells with 1 Ni-Cad cell to generate 3.2V electricity. By using this strategy, you could make a single large battery that would output the array of DC voltages needed. With this scheme the user would only need very simple regulators on the outputs.
The disadvantage would be the need for a more complicated charger.
Would this idea be a superior to using a 12V charging system?