Victron Energy Interface MK3-USB (VE.Bus to USB) The SmartShunt is a good

The SmartShunt is a good alternative for a BMV battery monitor

If you connect them to your battery and get a negative reading

It also has a built-in 45 amp battery charger which uses AC power

and two load terminals

Plug and play: Simply bolt or screw unit to the wall and make your PV and battery bank connections

Victron Energy Interface MK3-USB (VE.Bus to USB) The SmartShunt is a goodVictron Energy Interface MK3 USB (VE. Bus to USB) The MK3 USB allows the following products to connect to a computer for configuration and firmware updates: Multi, MultiGrid, MultiPlus, MultiPlus II, Quattro, VE. Bus BMS V2, Inverter Charger settings in ECOmulti, EasySolar, EasyPlus, and Inverters with a VE. Bus communication port.