For the HV (High Voltage) and LV (Low Voltage) cutoff's I purchased these relays from Mouser electronics:
https://www.mouser.com/ProductDetail...rrencycode=USD At $5.68 each....way less costly than the big contactor that ZEVA sells.
As for the "hook up" of the relays....take a look at this setup (my setup) and if you have questions please ask.