1 Throttle and 2 Controller with Regen

I want to connect two controllers to a single battery and a single accelerator.

I understand that one of the controllers I only have to connect the signal cable of the accelerator and not connect the positive and the negative.

In the case of regeneration with a single button, how should I proceed?

Any idea?

There are two ways you can go about this:

I'd suggest doing what you were suggesting in the first post, it will work as long as the controllers are identical and the lengths of wire from battery to each controller are the same or nearly the same. If the wires from battery to controller 1 are a different length from battery to controller 2, you can get glitching or oscillating power. I'd also suggest using the lowest gauge of wire practical between the controllers for power to minimize resistance and difference in each controller's ground voltage. (12 AWG).

The second approach, if you are into microcontrollers, is to use a microcontroller (AtTiny?) in each controller communicating over an opto-isolated current loop serial bus, with the slave controller outputting PWM through a capacitive filter to drive the second controller.