This posts tells you how to make a simple 3 state battery charge level indicator circuit 3 LEDs and a couple of opamps
To find out the condition of charge in which a battery is positioned, this circuit has been developed according to a window comparator using low consumption operational amplifiers. The circuit utilizes three LEDs (D1, D2 and D3), attached in between their outputs, to indicate one among three probable states in the battery: full charge, moderate charge and discharged.
The circuit is driven via a 100mA fuse, despite the fact that its consumption is merely around 20mA, it is provided with straight to the terminals of the battery that it may monitor and it can achieve this task with batteries involving 6 and 12V.
Through the variable resistors RV1 and RV2, the voltage levels V1 and V2 are tweaked that on which the red and yellow, and yellow and green LEDs turn on or off.
To give an example, think about the situation of a 12V car battery, using V1 equal to 12V and V2 corresponding to 11V; in this instance, the green LED lights up using 12V or maybe more, the red lights at a voltage lower than or of about 11V, and the yellow continues to be illuminated in between both of these voltages.
Tested Prototype Image