The following circuit is design to measure Li-Po and Li-Ion type batteries with a nominal voltage of 3.7V. EveryCircuit does not allow the addition of 2.5V LDO regulators, so the 2.5V supply power belongs to this regulator connected to the battery, which is represented on the left side with a voltage range between 2.8V and 4.2V. The output is intended to use CMOS inputs from a MCU. The resistors have standard E96 values. You can try to decrease the current consumption of the circuit by increasing the resistor values x10, however, you could have problems with external noise. You may try this by using rail-to-rail low-power OpAmps.
