Hello, I want to turn on/off my bike with Arduino. I want to place a relay or sth like that between ESC and the battery pack. The problem that I have is that the peak power of my bike is 4kW, and I would need sth that can switch 40-60vdc, which can handle up to about 100A. I was looking for relays that could handle that, and the only thing I found are relays that cost about 300$. Is there any cheaper and better way? If it changes anything, it would actually turn on/off when the bike is not moving, there won't be any sparking I think.
The ESC is already capable of switching off the battery pack. Why do you want to add an extra piece?
Instead, find out how to interface the Arduino to the ESC on/off logic.
Or … maybe you can interface with the existing control system ,
I know esc can, but i would like to add additional cut off from arduino
Look for a "Contactor" instead of a relay. Looks like a 48VDC 100A contactor is about $35.
You may be able to use a cheap ($20?) 'starter relay' like this one: