I have a home made meter panel that I use to watch the BATTERY LEVELs on when we are OFF-ROAD camping without shore power. When it gets down to around 12.0VDC (APPROX 50% charge level) I get excited and try to get them re-charged again...
This was a favorite meter to get a few years back called VOLTMINDER model 71730. I have one of these in my Truck. I think the company has since then come out with a newer version. This has a settable alarm for low DC voltage...
Another popular unit is this unit... Trimetric model TM-2025RV... They too may have an updated version out now as well...
All photos Google images...
Roy Ken
