I found this a useful webpage when trying to figure out what to do about floating a lithium
battery :
https://nordkyndesign.com/practical-characteristics-of-lithium-iron-phosphate-battery-cells/
Not sure about other manufacturers but
Victron state their batteries must be held at “absorption” (that’s 14.2V for my
battery) for at least 2hrs a month I assume this is to allow the
battery management system to balance the cells and recalibrate the state of charge.l
The float voltage specified is 13.5V it’s safe to keep them in this for the rest of the time. However, there is a slight advantage of keeping them at less than 100% state of charge over times when you are not using them but lithium batteries last so long anyway it’s more likely the rest of the van falls to bits before the
battery!
The main issue with lithium is not to let them go to zero charge at any time so it’s important to fit something to cut the supply when state of charge is near zero.
This is also why I leave my charger on when leaving the van for a while just as a backup in case there is something discharging the
battery it’s better not to go to zero than keep batteries at 100% state if charge. I think this is in line with Victrons recommendations.
Hope this is helpful!