Note that the solar panels are not necessarily the primary energy source, they can do trickle-charging, range extension and/or emergency recharge / supply (e.g. when you've run out).

These are roughly the use cases lightyear one tends to cover, under a somewhat ideal 12km/h WLTP (that is in good sun the panels can charge 12km worth of WLTP range per hour, which can extend the range during a drive, recharge a parked car or let you drive at 10~12km/h when the batteries have run out).