On my 80 series tourer, my Victron 75/15 and Monocrystalline 175W Panel had been working well for 4 years. Last month I noted that on the Victron iPhone app the minimum battery levels recorded zero! Any ideas why it not recording the history correctly? As previously, its lowest history recording was always 12.3v and the the bulk, float etc alway showed charge bars daily. I tested the voltage coming from panel and from the leads input and it read 12.3 v (as did both my batteries). But normally, after a day of full sun (today ) the batteries should be 13.4v. I've re set the controller and updated to the latest firmware. Any ideas?