I know this new one isn‘t using solar power at all, because they keep having trouble with dust building up over the storm season
1: Windshield wipers are extra weight, which would mean sacrificing some piece of scientific equipment. Weight is a premium on any space mission. 2: They would need extra power. 3: Windshield wipers have complex moving parts that can be clogged by the dust. 4: Wiping the dust over the solar panels would cause the dust to scratch them, reducing their effectiveness rather than improving it. 5: The rovers were expected to last six months. The fact that they are still going over eight years later suggests that windshield wipers for the solar panels were not actually necessary, doesn't it?
The rovers were expected to not last more than three months, so there was no expectation that dust might accumulate on the solar panels. When every gram had to be accounted for, nobody would be crazy enough to put windshield wipers on a solar panel. Hindsight is 20:20!
The effects of the winds clear the panels as much as cloud them over with dust. That's why the panels have operated well beyond their intended design life. The rovers were only designed for a short operational life and have exceeded that life because winds occasionally clear the panels. Putting additional systems on to keep the panels clear would've meant more weight and therefore less instrumentation's for the experiments. The new one doesn't use on solar panels because it's the size of a sub-compact car, it would take too many panels to power it and it's experiments. However, it's descent by crane from the lander was designed to prevent the rocket exhaust from getting dust on any solar panels had they decided on panels for power. A little more planning up front would've saved some of the billions spent on that rover.
