2006 Toyota Prius 96000 miles I had both my 12 volt battery and hybrid battery replaced within the last week. I was getting on average 45.6 miles per gallon. My first week average now is 51.1 miles per gallon. Could replacing the batteries cause my miles per gallon to increase, or is it just to early to tell?
Great question. I have heard people say there MPG starts to decline a sign that the 12volt is failing, and replacing the 12v the MPG restores back to higher levels. I also heard a steep drop off in MPG right before a traction battery failure. Many things effect MPG, driving habits, terrain, weather, tire pressure, gasoline quality, condition of car, etc.
Yes, if the 12V battery had a shorted cell, that will cause loss of MPG.How much the traction battery affects the MPG is dependent on how the car is driven, and in what kind of terrain. Mostly flat highway driving should use the traction battery very little, so it has not much impact on MPG. Very hilly terrain makes much use of the traction battery, so it is important to have a good one for good MPG.
