Battery Diagnostics Breakthrough Battery Tester Reveals Voltage Fluctuations

I replaced the original battery this past January and had no issue until this past weekend in the middle of a 900-mile road trip. While cruising ... I don't drive it that often. Maybe it's normal and something to do with recharging the battery after extended idle periods. Has anyone else ... The voltage at the battery should not drop below 12 volts engine off for a healthy battery, and not go above 14.5 when running. You may have a battery or ... I got in the car. Checked voltage before and after starting It. Voltage hits 13.7 volts for a breif second after starting then drops to battery ... A good battery with engine off should read 12.5vdc. Your charging system (DIC) when running should read about 14.2vdc. My latest issue is that every 2 or 3 days the battery guage will drop to 9V and she won't charge. The alternator tested good at the parts store. So, it kinda sounds like your battery is not being charged during acceleration. Or else, something is drawing more current (dropping the voltage) ... The battery is still fluctuating due to prior charging/discharging (no full rest); The battery has been moved (especially from in- to outside of ... They will intentionally let the battery charge drop while driving - battery voltage will drop to around 12.6v or so when this is occurring. While I am driving, I see that my battery voltage goes from 13.6-14.0 to 12.2-12.6 volts and it keeps on fluctuating like this every 30 seconds or so.