On the way back up to the US currently Nicaragua. I noticed that my voltage guage was reading lower than it should ... maybe 11 or so. No battery voltage light ... group 31 battery 5 years old. Headlights aren't dim or anything and she starts up fine ... I stopped, checked terminals etc. I don't have a voltage meter with me. Voltage indicates the same even under acceleration and a high rev blip on the throttle makes it move up a fraction but barely noticeable. I'm thinking windows are on a battery lead circuit and headlights off the alternator? Hunch is a bad cell in the battery. It's middle of the night here and not really any place to check it out at the moment. Had to hunt for a bit to find cell service. Thoughts ?? Maybe check the magnetic pull on the alternator... if that will tell me anything on these 100 series. Should I do the old school pull the negative battery lead off while she's running and see if she still runs? Shut her down before reconnecting and all? Or will this toast my electronics like in new BMWs? Checked the fuses and all look good to go. Strange the battery light isn't on, but maybe because that measures output from the alternator as d the batter is showing low voltage on the dash because a cell is toast?