eli5/Electric cars


There is so much discussion about charging stations and batteries being barriers to producing economical, practical electric cars that can travel long distances without charging. (I live in Australia where distance is a real ‘thing’)

Am I missing something?

Why can’t such a vehicle use a “dynamo” system to produce its own energy once in motion?

In: Engineering

Conservation of energy.

A dynamo uses the energy of movement to create electrical energy.

But you need electrical energy to move.

Because as they’re driving, they’re expending energy, and even with a high efficiency dynamo system, it wont ever be able to produce as much as it’s expending.

Imagine if the car is using 100W/m, and the dynamo is only charging at 25W/m. Out of a 1000 watt battery, you’d only effectively get 2.5 extra hours of runtime.

My Tesla goes 300 miles to a charge, you can buy them with 400 miles of range and in a short while with 500 miles range which you can preorder now.

You cannot pull energy from a moving vehicle without causing it to slow down or otherwise become less efficient. EVs and hybrids actually use this technique to their advantage when slowing, this also saves on brake wear and slightly will add charge to the battery.

The contiguous 48 states of the US (excludes Alaska and Hawaii) is around 20% bigger than Australia and has about 7.5 times more roadways. That being the case, Australia should be an easier candidate for electric vehicles. It’s a smaller country, with fewer roadways, and a smaller and more separated population so that charge stations could be relatively concentrated and serve a large number of vehicles.

That said, the materials to manufacture batteries of that size are the real discussion in economic feasibility. It basically boils down to whether or not we want to strip mine all of Bolivia and Australia for lithium and the Democratic Republic of the Congo for cobalt.