Higher charge/discharge current can distort the voltage the charging source “sees” at that source's BATT terminals. For example, f the battery battery bank is actually 13.0v and the charger is putting out a lot of current the battery voltage might appear (to the charger) to be 13.4v. This can cause undercharging due to early Absorption termination.

This effect is aggravated by undersized wiring.

To limit this effect some chargers use a separate Voltage sensing¹⁾ circuit to get a more accurate reading of the bank voltage. The sensing circuit is not affected by voltage distortion because the sensing current does not carry significant current.

The Victron line uses the Smart Battery Monitor, Smart Shunt, Smart Battery Sense to send voltage info via bluetooth to SmartSolar controllers (built-in BT) and BlueSolar controllers (using an add-on BT dongle).

Most other controllers use dedicated sense wires, which are often just plain wire. Some controllers have special connectors which might require a proprietary sense wire (see below).

The Renogy line uses a sense wire like this to send remote voltage info to these controllers:²⁾

• Adventurer Li 30A
• Rover Li (60A, 100A)
• Rover Elite (20A, 40A)

Renogy

• Rover Boost 10A
• DCC-series DC-DC chargers (30A, 50A)