If your going with the "CAN Bus" charger like this one
https://www.elconchargers.com/catalo...0/10295151.htm then I would advise buying it from Electronic Conversions in California. (The link)
They will program it properly so you can do your charging parameters with the ZEVA. I purchased mine from China and thought I was getting one set up for making changes.....but they sent me one "hard-wired." I then sent it to the California guys to make the changes.
The monitor is really a must for the ZEVA.
The contactor setup is somewhat expensive. I went with relays as they are just as effective and much less $$$.