The battery can be charged from two sources at the same time. Charging the battery from the grid is usually set to 15A or 720W as opposed to charging from solar where there is no limit apart from the battery’s maximum charge limit. To put the charge rate into perspective. – If the battery is at 50% State of Charge or SOC it will require 2500Wh to be charged back into the battery. When charging from the grid at 720W, it will take roughly 3.5 hours to recharge the battery. When charging from solar power it charges the battery from an empty state in a little over 2 hours. This being the case means it’s much better to charge batteries from solar as opposed to grid power for two reasons. 1. Charging from the grid is slower and you end up paying for the power charged to the battery. 2. Solar charging is faster and the power generated from the panels is at no cost.