Battery monitors typically show:

• battery voltage (Vbatt); and
• Amps or Watts in (charging) / out (discharging)

Watching amps trail off at the end of Absorption (endAmps) will also tell you when the bank is fully charged. The battery manufacturer will specify something like C/200 or C/100 as a sign Absorption is complete.

One benefit of having a shunt-based monitor over a charge controller monitor is the shunt can discern between [dis]charging vs [dis]charging+loads.

The most famous battery monitor is the Bogart Tri-Metric TM-2030 series.

This monitor will interface and operate their SX-2030 solar charge controller. The monitor will still provide amp-counting and other metrics when used on it's own.

For folks who are [dis]charging at 50A/75A, a cheaper shunt is available for 1/5th the price of a Bogart.