3.4V for an LFP cell is 100% SOC. This is 13.6V for a 12.8V battery...Course with the cost of LFP now well below that of AGM who cares just replace them when you kill them......
This testing was very enlightening regarding charge voltage, charge time and actual capacity of a particular charged voltage. You can skip to the end for results or differences between 3.45, 3.55 and 3.65. Really the only benefit was charge time.