Hi everybody. Owner of a Multiplus Compact and a smart solar hq1814. Since yesterday, after successufully charging with AC or solar, and reaching 14.4 volts, suddendly it goes down to 7.7. It also occurs when starting the webasto heating, that then says there is not enough power in the battery. Tried with "charger only" and with "on". Same results. It even happens while solar charging. From 14.4 to 7.7 in one second. Any help?