Note - I have tagged this as hard-science because, apart from feasibility, I'm hoping for some actual numbers that will tell me the capabilities of such vehicles.
Background
On a planet far away there are constant thunderstorms over the plains of Groth.
Until the advent of science and technology, the locals kept well away from the area, despite what would have provided excellent trading routes. This was because the chances of you and your pack-animals surviving were minimal.
Now however planet-wide electrical technology has reached the level of early 20th century Earth. Gasoline-powered vehicles have not been invented.
Someone has the idea that the Grothlanders would be the ideal people to test out the newly invented electrical motors because they live all around the perimeter of the Plains. There is a continual although not exactly continuous supply of electricity from lightning.
How the vehicles work
They are 4-wheeler carts steered from the front and powered by an electric motor driving the rear axle.
They have an aerial sticking out of the top to catch the frequent lightning strikes. The driver and passengers are protected by a Faraday-type cage to avoid being killed. They have padded helmets to muffle the constant deafening noise.
Question
Given a lightning strike every few minutes, would such a vehicle be feasible? It has to travel up to 100 miles across the Plains of Groth on any particular journey.
In particular, is it feasible to catch, store and use lightning in this way and would the weight of all the necessary equipment to make this work be excessive?
Assuming that the idea is feasible at all: Given the energy of a typical Earth lightning bolt, how often on average would a minimal-sized vehicle have to be struck in order to keep going pretty much continuously at, say, 30mph (approx 50kph)?
Assumptions
Please ask for further necessary details before answering.
A minimal-sized vehicle has condensers to store the electricity, an electric motor, is capable of driving hundreds of miles whilst being struck by lightning, carries a human-sized driver and one passenger, and a Faraday cage to protect them. The plains are more-or-less flat with firm but wet going. Some suspension is necessary but there is no rough terrain. Ball-bearings are available.
There are future plans for some kind of railway network. But but this is still years away. For now, all they have are self-contained 4-wheeler motor carts. Most of these are home-built apart from the electrical motors that they have to purchase.
The lightning storms are equivalent to those on Earth but go on day and night through some climate anomaly not disclosed here. If you venture onto the Plains you can expect to be struck pretty regularly. Exactly how often is part of my question.