[BlackNitrogen]

You don't need ultracapacitors, regular ordinary teslas starting with the 2012 model S have had this. It's not quite a decade old.

[mikepurvis]

Do you have a source on that? This article, for example, on the Tesla website is clearly aimed at a lay audience, but nonetheless mentions nothing about an intermediate capacitor bank for absorbing spikes of regen braking energy:

https://www.tesla.com/en_CA/blog/magic-tesla-roadster-regene...

[BlackNitrogen]

I don't get your question. But that is a roadster, not an S or later. But it presumably doesn't mention intermediate capacitors because they don't use them.

[skykooler]

I think you and mikepurvis are both saying the same thing - that Tesla and other electric cars are using batteries only, not capacitors.

I will note that the homebuilt electric cars generally had much smaller battery packs, which could not supply the same peak currents that a 50+kWh battery would have.