Satellite is launched, goes silent after a few years due to electrical problems. Decades later, the onboard batteries have deteriorated such that they're just a short (no storage capacity), and the satellite works intermittently when the solar panels are exposed to enough sunlight.
There's probably some charge control electronics, but that's the gist of things. When the battery is discharged or shorted, the solar panel would need to raise the voltage to power the load. When the battery fails as an open circuit, the solar panel can power the load directly.
Satellite is launched, goes silent after a few years due to electrical problems. Decades later, the onboard batteries have deteriorated such that they're just a short (no storage capacity), and the satellite works intermittently when the solar panels are exposed to enough sunlight.