A low voltage disconnect is used to stop loads from dragging a battery bank below a given voltage.

In most installations all loads go through the LVD except the inverter, due to the heavy current draw. The inverter will have its own internal LVD.

Lead-acid deep cycle batteries last the longest with best capacity if they are never cycled more than 50% Depth of Discharge¹⁾. That point is somewhere around 12.10v.

LiFePO4 nominal 12v banks can be safely drained to 80-90% Depth of Discharge. That point is something like 12.0v.²⁾

LVD rely on measured voltage to know when to disconnect, but heavy loads can distort that reading.