[mpg_numbers_guy]

If your battery is staying at 6/8 bars most of the time then you probably have a healthy battery....a telltale sign of a battery that is about to fail is one that goes from full to empty repeatedly and rapidly in just normal driving (not counting long descents and regen situations, or prolonged use of EV mode). Dr. Prius gives more info with a diagnostic test that lets you test the individual resistances of each cell in the battery, bad cells typically have resistances that are significantly different from the rest of the pack.