1, the charger's float voltage is too high, higher than the standard float voltage. The higher voltage difference raises the float charging voltage of the single 2V lead-acid battery.
2, caused by the imbalance of the battery pack. Battery pack after a period of time, by the influence of various factors, the battery capacity, internal resistance will usually occur differential changes, especially the capacity. The change in capacity is also usually reflected in the voltage, for example, a battery with reduced capacity has a lower voltage during discharge and a higher voltage during charging (including float charging), which is higher than the average value.
Suggestion:
If it is the first reason, please reduce the output float voltage of the charger according to the charger's setting.
If it is the second case, relying on float charging or forced equalization can not completely solve the problem, if you have the conditions, please use the active equalization technology equipment to equalize the battery pack, not only for voltage equalization, but also for capacity equalization.