Originally Posted by LifesBetterWhenYoureBeating
I'll have to change it on each charging source.
So I'd just set the absorption voltage to something like 13.4? Do I need to change the float voltage as well?
Yes. Sometimes chargers have separate bulk and absorption numbers if so change both to the same lower value. Sometimes they just have a single
absorption value which controls both bulk and absorption. If there is an absorption time it may be very high (like 4+ hours) which will cause the Soc to rise significantly so you may want to reduce that as well down to 15 minute to an hour depending on the charger output compared to battery capacity.
Ideally float voltage is already down around 13.4V or lower. LFP don't really like to float charge. So "float" isn't really being used to charge the battery but rather power
low always on loads so the battery doesn't discharge.
Resting voltage of LFP is around 13.4V. Even if you charge it to beyond that and the battery voltage rises higher (13.5V to 14.6V measured when resting = no charge or loads) that ends up being a surface charge which quickly bleeds away and the voltage falls back to around 13.4V once charging source and loads are removed usually within a few hours but at most 24 hours.
So 13.4V or even 13.2V "float" is a good value for LFP. It is right at or just below the resting voltage of the battery and very likely will never charge the battery just ensure it doesn't discharge. If heavy loads come on the float output won't be enough to cover them and then energy will flow out of the battery so voltage will drop causing the charger to go back to bulk/asborb to refill the used capacity.