How does the Sparkfun couloumb counter (LTC4150) work with a charger?

Thread Starter

Joe Stavitsky

Joined Apr 5, 2020
107
My understanding of the couloumb counter is that it integrates over time current _leaving_ the battery. However, one of the first pictures here

https://learn.sparkfun.com/tutorials/ltc4150-coulomb-counter-hookup-guide

shows a charger ic connected across the "out" terminal. If current is flowing in the opposite direction, how is the count accurate? Does it simply integrate the "negative" current?

Thanks so much

Joe
 

nsaspook

Joined Aug 27, 2009
10,715
Yes. The typical 'counting' routine uses signed numbers and functionality so "negative" currents are not a problem. The problem is Coulomb counter accuracy over the short and long term as an indicator of electrochemical battery health and State of Charge as it measures charge movements, not actual energy storage per unit of charge in and out of the battery for capacity calculations.
https://www.analog.com/en/technical-articles/accurate-battery-gas-gauge.html
https://www.pveducation.org/pvcdrom/battery-characteristics/battery-capacity

Hall sensors used in a battery monitor to track charge and discharge currents.
https://forum.allaboutcircuits.com/...c-controlled-battery-array.32879/post-1488959
 
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