https://www.fordforums.com.au/showth...1449262&page=2
See post #37.
That should be done when the battery is replaced. If not, the theory is that the BMS determines that the battery is older than it really is and turns off loads to ensure reliable starting.
The BMS system aims to keep the battery at 80% full charge, ie you lose 20% capacity right there. Low battery warning is a common issue on these cars, but they usually seem to start OK. Unless the battery is really low...