I assume you don't really care so much what the voltage is, as much as what the the state of charge is? Knowing the current flow at the charging voltage is useful. You can determine the current by placing a low ohms (e.g.. 0.1Ω) shunt resistor in series with the charging current, and measure the voltage drop across the resistor. A ∆V of 1V across a 0.1Ω resistor indicates 10A of charge current. The resistor needs to be rated to at least 2X the estimated power dissipation (I^2 x R) to avoid overheating. And you need to know how the charge current relates to state of charge at the applied voltage.How can i continue to measure the voltage of my battery as it is charging with an indicator circuit without reading the voltage coming from the charger circuit.