When Will My Mpg Improve On My New Prius

I beg to differ - not with the causes, which are all good, but the amount cold weather makes. If you look at TonyPSchaefer's mileage chart with temperature, he's showing 50% difference from the coldest winter temperature (40-45 mpg) to the warmest summer temperature (60-67 mpg). My own rough guess based on memory (I don't chart the temperature) is about 30%. I have a shorter commute than Tony, but similar weather - highs in the 80's, some 90's, lows around zero (F). We both block our grill in the winter, or the difference could even be more.

Temperature and length of commute are the two biggest factors for fuel economy, with driving style and tire pressure running right behind. (Extremes on any of these could tip the balance).

 

When you are coasting, with the arrows directing energy into the battery, your are USING ENERGY to charge the battery at the expense of coasting. Remember, nothing is free. If you use the energy to charge the battery,your coast will be shorter.

As long as you are going to continue to move (not having to stop or slow down for a light etc) the ideal is to coast to maintain as much momentum as possible, rather than letting the energy go back in the battery thereby using up the kinetic energy of the car moving. Remember, it takes more energy to charge the battery than it gives you. (I believe it is called the Perket effect (?)) I don't know what the efficiency of the Prius battery charge system is, but in a typical solar energy situation, for every amp/hour your charge system provides, it only puts in ~.8 amp/hours into the battery. The internal resistance of the battery counts for much of that loss.

Bottom line, keep as much momentum as you can always, and when you NEED to lose that momentum, avoid the friction brakes and charge as much as possible. The best way to get your mileage up (aside from grill blocking, ebh, etc) is to anticipate the road, slow down to avoid stopping whenever possible. It takes way more energy to get a mass moving than it does to keep it moving. There is no magic, just good habits.

Icarus

 

tire pressure tire pressure tire pressure keep the psi over 40 and block your top grill.

 

My new 2008 is 3 days old. I just finished a 200 mile trip at 75 mph on the turnpike. Got a solid 47 mpg. Total miles on the odometer is about 330. If there is a break-in period it must be short. Yes the temperature is warm (Florida). I am still impressed at that speed.

Bob

 

Most people report a 5K break-in period with some reporting a secondary break-in. You should see an improvement after your first service, however who knows how much of any improvement is attributable to the break-in of the car and/or the driver.
Enjoy,

 

Funny you should mention the porsche. My other car is a 1993 911 targa. I also drive the hell out of it while careful and always watching my fuel economy in the prius. The worst milage I have gotten in the porsche was 14 and that was whipping it in the Rockies. Best I got was 27 cruising at 55-60 on highway. The prius on the other hand averaged 52 on a round trip from the eastern shore of Va to Boston and back. That was with 3 of us in the car moving at speeds of 65 +/-. The milage seemed to improve once we got off the flat lands of the Shore and into the rolling hills of New England. I also found that some drafting behind big rigs and lines of cars moving at speed really improved the milage.