For the record I will copy here Renogy's respond about how balancing works on their batteries :
"When the highest cell voltage exceeds 3.3V, try to charge with a small current (1a-3a), so as to increase the equalization time and equalize the opening conditions (single cell > 3.36v, voltage difference > 40mv, open equalization)"
"When the highest cell voltage exceeds 3.3V, try to charge with a small current (1a-3a), so as to increase the equalization time and equalize the opening conditions (single cell > 3.36v, voltage difference > 40mv, open equalization)"