It is sometimes recommended to do an equalization charge several times a year depending on how frequently the batteries are cycled.
Over time, the voltage of the individual cells can drift causing inconsistencies between the cells. The equalization charge helps to reset all the cells by basically overcharging the batteries to take all the cells up to their maximum charge levels. during an equalization charge, you can see the battery voltage exceed 61v.
The Sunny Islands attempts to track the 'Battery state of charge' (Batsoc) but it can get out of sync over time where it might think the batteries are more charged than they really are. When this situation occurs, the inverters might drop down to 20% suddenly because of the battery voltage falling down too low below 48v. Equalization charges can also help this situation because it essentially over charges the batteries.
Equalization charges can take 10+ hours to complete. The EQUALIZATION charge mode along with the remaining time will be displayed on the Master Sunny Island inverter as it cycles through the status screens...
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