In SCR controlled chargers, the DC sends output to the battery as a pulse of current each half-cycle of AC supply. During the time when the AC is crossing zero, in between pulses of output, there is no current flowing from the charger to the battery. During this time, we use a sample-and-hold circuit to measure the battery voltage without errors that could be caused by drop on DC cables. This improves performance and eliminates the need for separate voltage sensing leads.