Electrical Power Ghost - Any Suggestions?

[MonroeWA]

Question: My van sat for a week and now the display is showing between 3 - 3.5 and neither running the van nor plugging it in is charging the batteries, and the inverter does not appear to be coming on. The breakers and fuses above the drivers chair are fine so I'm wondering if the AMG batteries would drop dead that quick or if a fuse I haven't found could have blown. I've read that if the batteries are so low that they won't charge the inverter, it might cause these symptons but I would have thought running the engine or plugging in would kick things up and start the charging. Any suggestions? Thanks much, Tod