The voltage of my LifePO4-Battery Bulltron Polar 165 Ah dropped for some hours. During that period the GL520 voltage readings showed gaps. After some hours the voltage was back to 13,25 V and stable with continous readings. Any idea, what might have caused the Problem? The Battery is only 10 month old. Bulltron 165Ah Polar version. All loads are disconnectef, but the BMV 720, which is conected via VE-Direct cable to the GL520. Any idea?