I have a digital voltage meter that plugs into a cigarette lighter and has worked fine a years. I recently noticed it was giving me a reading of 9.4 volts. I checked the voltage meter on my master control panel and it gave me a reading of 13.3 volts for the house batteries and 12.9 volts for the engine batteries.
I removed the digital voltage meter from the cigarette lighter in the front dash and inserted it into a cigarette lighter in the bedroom and again, it gave me the same reading of 9.4 volts.
Little bit concerned and was wondering if anyone had any suggestions as to why the discrepancy between the two meters. Here is a picture of the Digital Voltage Meter I'm referring to.