You can power any vehicle stuff - vehicle welding rig, kitchen unit, FOODCO, vehicle chemistry set and vehicle electric forge.
You connect two (or more) vehicles with jumper cables and they share power. You can have one vehicle produce power and other one use it up. This could be useful in an underground base where you want to keep the gasoline engines from your crafting rig to prevent getting smoke in your face.
You can also start a battery-less (or power-less) car using power from another car.
Unfortunately you can’t have an aboveground solar panel array connected to underground crafting rig.