I am trying to understand the relationship between AH and WHour for lithium batteries. I know the Watthour=AH x voltage formula. What I am trying to understand is for a 12 V lithium battery how a smart shunt or BMS measures the AH in relation to WH. Does it use 12.8V or 13.3V or something different? When a shunt gives a AH value is it multiplied by nominal lithium battery voltage or 12.8 which is lead acid battery voltage? My shunt seems to use 13.3V approximately but it seems to change. it shows both AH and WH values. When I purchase a LFP battery does the seller advertised AH base on 12.8 V therefore with smart shunt should expect less AH?