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

 

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

 

Please read the attached, especially the section titled "OPERATION"