Setup: 4s 12-206Ah SOK LFPs. wired in series for 48V on an off-grid solar setup.
History: Used first in summer 2022, worked great. Batteries disconnected from system over winter.
Status: Spring 2023 individually charged each of 3 of the batteries full with the Victron BlueSmart 12V/15A IP65 charger
Problem: 1 of the batteries will not charge. While disconnected it reads at about 6.2V. When initially connected the charger reads about 7V/15A (via BT app) during "Test" phase but after a few seconds goes to "Absorbtion" at 14.4V/0.0A. I've repeated this several times with the same result.