A good quality battery monitor can also be made using a LM324 IC. LM324 independent low power operational amplifiers. In this circuit we have used all the four operational amplifiers, each op amp is working separately as a comparator to monitor a certain voltage point set by the 10K variable resistors.
The circuit is versatile and can be used to monitor just about any type and voltage of batteries, the tuning / adjustment for a desired battery can be done with the 10K variable resistors. For adjustments you will also require a adjustable power supply.Â