I'm working with a device which will use Lithium thionyl chloride (non-rechargeable) batteries as a backup source; their discharge curve is quite flat and AFAIK you can't tell how is the battery in terms of whether it's good or about to die (EOL) unless you apply a dummy load. There are other more complex methods but my application requires me to save every penny and the client just wants to know if the battery is good or dead. Now the circuit is working but I would like to make sure If I'm actually doing it correctly or outright far from the right path.
- If this method of applying a dummy resistor when needed and measuring from the ADC at that time a legit method?
- If I should be concerned that the voltage divider and the ADC might eventually drain the battery, I added a MOSFET to cut off or connect the path between the battery and the voltage divider and ADC.