Maximizing Battery Life: Using Load Droop to Detect Charge Level

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Akmalidin
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Hello,

I am building a power bank myself and want to set put detector that determines the voltage level and indicates it in LED (4 LED are planned to be used). I know how to make it with transistors and op amp. But I was wandering if there is any IC chip that does it?

Thank you,
Akmalidin Alimov
 
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The voltage of a battery isn't always a good indication of the state of charge. Battery voltage also varies with age and temperature and technology.

Google battery monitor ic. Companies like Maxim have a range. Might be easier to buy a ready built module off ebay
 
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Chips designed to provide battery state of charge information are typically listed as battery fuel gauges under supplier categories. Though you can do what you want pretty simply with an MCU using its ADC. For some battery types open circuit or light load voltage can provide a good gauge for state of charge. For other battery types It doesn't work as well. Lithium-ion and lead-acid can be gauged well enough using open circuit voltage as long as temperature is not extreme. Primary batteries such as alkaline can also be gauged that way. Problem is battery voltage drops under load depending on current draw and battery internal resistance (which can vary due to temperature, battery wear, and state of charge). You may need a mechanism to deal with those factors depending on how accurate your gauge needs to be.
 
Another way to determine the state of charge of batteries is to momentarily connect a load representing the maximum load you expect the battery to see and measure the amount of droop. As the battery charges, the amount of droop will decrease. You would need to decide the amount of droop that would represent a full charge.