That is exactly the point, Joel. Upsizing 20% is several times more expensive
compared to providing an intelligent switcher to match to the illumination or to
adapt a panel voltage that isn't matching the storage devices. That situation
won't change unless there is a tremendous breakthrough in technology or serious
new government subsidies.

As to reliability, a switcher that is designed correctly and conservatively
should easily outlasts the cells. Even for small installations it is easy,
especially in view of the large variety of micro controllers that retail for a
few Dollars. One of these plus a few discretes and an inductor can do the trick.

Regards, Joerg.