Victron VE.Bus BMS V2. SMART BATTERYPROTECT 12/24V 65A. Cost will depend on Size, Weight & Location. When using Bluetooth to program the Smart BatteryProtect any required engage/disengage levels can be set.
Had one of these fail once before, but still bought another of the same brand as I think I was just unlucky. I know these are a quality product and brand.
Excellent quality product. If you need fully adjustable cut-off and restore voltages (by the bluetooth app), with very low current drains in supply and cit-off modes, this is the one to get.