The BYD BCU Battery Control Unit is compatible with all BYD HVS and HVM batteries and is supplied complete with base plate, cover, BCU and wall bracket. The BYD-HVS-Base-Cover is an essential accessory to the BYD high voltage battery system. For the HVS, a minimum of two modules is required per battery tower, with a maximum of four or five modules (depending on the inverter). For the HVM, a minimum of three or four modules is required per battery tower (depending on the inverter), with a maximum of eight modules. A maximum of three battery towers can be combined in a storage system.