Simple question with no simple answers.
As soon as lightning enters the wiring of the windmill, solar panel, power wires, data cable, or any structure, the huge voltage can deliver a similarly huge current. Anything else connected to the component that's struck will also be vulnerable to a high indirect voltage. The indirect voltage can come in at high or low potential, forward or reversed polarity, and a very high or low current can result. All very hard to predict. No, impossible.
If lightning currents flow in loose wires, they can actually move or whip around.
If lightning currents flow through a battery, the liquids could vaporize and explode.
Lightning has been known to heat small wires enough to vaporize them (that's anecdotal).
Your best protection is a thorough and systematic attention to grounding the whole system from tower to the inverter. One arrester wired to a stake in the ground will not do. Could even make things worse. The grounding system has to suit the system you have, so it's hard to put a bunch of general advice together.
If you subscribe to HomePower magazine, you can read their Code Corner for a lot of instructions.
One last point: don't listen to me. My wind turbine isn't perfectly protected either! I still don't have a ground bus separately installed from the negative bus bar...
