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We are trying to design a low battery indicator and full battery indicator for 1.2V NiMH batteries. Possible types are two batteries(2.4V) in series or three batteries(3.6V) in series. Can someone give me a few pointers or if possible a circuit diagram?
According to a typical NiMH discharge curve at low current levels, if you detected a low voltage of 1.15V, the battery would have perhaps 5-10% of it's charge remaining. Beyond that it's not possible to reliably determine the state of charge of a NiMH battery from its voltage.
We decided on using the Energizer 2450mAh AA batteries. I looked up a few graphs of the voltage Vs Time and saw that the fully charged battery can have upto 1.6V.
Assuming we use 2 such batteries I can make a Low Battery Indicator with a MAX8211 for 2.3V minimum input(1.15x2).
But what about a charge level indicator for the actual charge on the battery like green for fully charged, orange for partially and red for exhausted battery? Can someone help me design a circuit for that?
We decided on using 2 Energizer 2450mAh 1.2V batteries.
I checked out its graph for voltage Vs Time for varying discharge currents. It says its voltage can go upto 1.6V when fully charged.
So I can make a Low Battery Indicator for 2.3V(1.15x2) using a MAX8211. But i was kinda hopin for an actual charge indicator like green for full charge, orange for partial charge, and red for complete discharge. Can u help me design something for that?