Here is Morningstar's description of Voltage sense.
TriStar TS-45 PWM wrote:
4.3.2 Battery Voltage Sense
There can be voltage drops typically up to 3% in the power cables connecting the battery to the TriStar. If battery voltage sense wires are not used, the controller will read a higher voltage at the controller’s terminals than the actual battery voltage while charging the battery.
Although limited to 3% as the generally accepted wiring standard, this can result in a 0.43 voltage drop for 14.4V charging (or 1.72V for a 48 volt nominal system).
These voltage drops will cause some undercharging of the battery. The controller will begin PWM absorption, or limit equalization, at a lower battery voltage because the controller measures a higher voltage at the controller’s terminals than is the actual battery voltage. For example, if the controller is programmed to start PWM absorption at 14.4V, when the controller “sees” 14.4V at its battery terminals, the true battery voltage would only be 14.1V if there is a 0.3V drop between the controller and battery.
DEF 1. Without Voltage sense, the battery Volts will eventually rise from 14.1 to 14.4.
DEF 2. With Volt sense, the battery Volts will be a constant 14.4 while the charger's Volts drop from 14.4+? to 14.4.
I believe DEF 2 is what the battery spec means to be done. Charge at 14.4V at the battery. The charger simply raises its charge Volts until it senses 14.4V. Voltage sense takes care of that.
HTH;
John
