I recently got my prius prime a few months ago and was told about this website for prius-related questions. I was looking for threads that might answer my question but either I didn't look hard enough or I'm just blind. Anyway, there are times I would have to use HV mode, either because the battery is depleted or because I have the car set to Auto EV/HV mode and sometimes the engine would be used where more power is necessary. In those situations, I noticed my gas number on the gauge cluster ticks down much faster than the miles are recorded on the odometer. For example, 1000 miles on the odometer and 300 miles in the tank. X minutes later in the highway, there's 1010 miles on the odometer but 280 miles left in the tank. How did I go through 20 miles from the tank but only 10 miles was recorded in the odometer? The numbers used in this example is somewhat exaggerated, but the point remains: I'm using more miles from the tank than the odometer is recording. I would even check my GPS to see how far I went from point A to point B and the fuel used never matches (or even closely matches) the distance traveled. I expected this from EV mode on the highway, since electricity is less efficient in faster speeds. But is it actually the same with hybrid cars? If it helps any, I don't drive with a lead foot. I typically stay 5 over the speed limit for side streets or 10 over the speed limit for highways. The car is about five months old with around 3600 miles on the odometer. I got it with 52 miles on the odometer. I typically drive using EV mode and then use the engine once per month, for around 50 miles to make sure the gas doesn't go stale, so I only noticed this issue recently. Is it because the odometer has mostly EV miles recorded, so gas miles is throwing the equation for a loop? My previous car was a used Corolla XSE (forgot the year) and I never got this problem on that car. The odometer would record the miles traveled fairly accurately on that car, so is this an electrified vehicle issue? It's my first hybrid car. Or is there some kind of internal issue that I'm not aware of?
When the engine first turns on, it is burning more fuel to try and get the engine and the catalytic converter up to temperature to reduce emissions. This start-up procedure will typically use more fuel. Subsequently, you are using the engine in situations where more power is needed which would use more fuel than necessary. This, thus, affects the estimate range that the car calculates. Flip it the other way around, if you were in hybrid mode but only used EV mode to accelerate, your estimate EV range will also go down faster than the accumulating mileage on the odometer.
neither the tank nor the battery hold miles. they hold energy in their respective forms. the 'guesstimate' on the screen is simply an estimation based on past performance which includes weather, hvac use, acceleration, speed and etc. the formula cannot predict actual miles, unless you were doing similar driving in similar conditions all the time. it's there to give you an estimate, but it's not written in stone.
