I apologize I should I posed it as a question... can't seem to edit the title. When I first got the Prius the range on EV was shown as 12.8miles, now as the car gets to know me, the estimated range is dropping. Right now it is around 12 miles. However, my observation is that unless I regen some amount during driving (at least 1-2 regen miles), there is no way I get the 12 miles on a steady driving condition. Is this expected? The next obvious question is how to get the best range. Do you accelerate at a slow speed, or do you hit the pedal (as long as it doesn't enter power mode), and then gently hold the pedal (lower quarter of the HSI) to maintain desired speed? I am trying to see which works the best. Fast acceleration and gliding seem to work better, but it is not always possible in traffic. One suggestion I can think for Toyota is that once the car is rolling towards a stop, maybe when it is less than 10mph (I doubt a lot of regen can be done at that speed), the gears should disengage, so the car can roll farther (helps in traffic lights). Otherwise, I have to accelerate a little to close the gap from the front car (which also suggests that while the car is getting to know me, I am still to get to know it).
with ev, it's all about speed, the slower the better. same with acceleration. and you want to use your brakes as little as possible. as to what's expected, you get what you get based on terrain, traffic, speed, number of starts and stops, weather and etc. 12 miles is a bit higher than epa. you can through it in neutral to disengage the gears when desired, but the tiny bit of juice you're using to close the gap is negligible. there might be an efficiency range for the motor, but no one knows what it is.
Strictly speaking, you can't disengage the gears at all in the Prius (Plug-in or standard). There simply isn't any mechanical way to do that. There are no clutches in the system. By tweaking how the motor-generators are energized, the system can cause them to spin freely, neither generating electricity nor providing thrust, so I guess that is pretty much equivalent to "disengaging gears".
To test different driving techniques - drive when nobody is on the road when the traffic lights are turned off. avoid rapid acceleration, accelerate on the downhill, decelerate on the uphill keep the top speed about 15 mph. Avoid stopping - most of the energy lost is due stopping.
131 MPG on my 39.2 miles of round-trip commute today, with a recharge at work. I have no idea how many miles of that were EV. I don't care either. It's the end result that counts. You do have the ability to squeeze more out by following suggestions, like driving slower, accelerating slower, and avoiding large hills. But it's still the same amount of electricity consumed in the end.
Acceleration matters little. Don't use brake (even regen). Avoid 55mph as half of energy loss is from pushing through air. Those two are biggest factors in energy loss.
Yes, relatively low speed and never touch the brake, nor do regen, is the best. Keep the hybrid system indicator out of the charging area on the left. So, the nice hybrid system given in this car allows you to transfer the motion energy into energy in the battery, but the very best is not to use it, or only use it by exception. This transfer comes with an energy loss estimated between 30% and 50%. In practice this way of driving means that you avoid variation in speed as much as possible, and in fact you keep a higher speed when making turns, or crossing roundabouts, for example, than drivers usually do. Be careful.
To be more specific, EV efficiency in the Prius Plugin is gradually and significantly improved as driving speeds are reduced until you get down to about 10 mph at which point things become less efficient as you approach 0 mph. Driving EV at 15 mph is twice as efficient as driving at 60 mph although even at 60 mph it is still very efficient. These are measurements by the Idaho National Lab on a 2013 Prius Plugin in EV mode with no gas engine running at steady state speeds on a flat road. The energy use is measured from the battery and so does not include the added overhead of charging the battery from the utility grid: 15 mph: 102 Wh per mile 30 mph: 121 Wh per mile 45 mph: 180 Wh per mile 60 mph: 205 Wh per mile This rule is generally true for all cars running in EV. In some other cars the speed at which slower driving becomes less efficient is a little higher speed like 15 or even 20 mph. Some other cars can also drive in EV at speeds higher than around 60 mph but they will also gradually become less efficient with increased speed both due to the electrical powertrain itself and increased wind resistance. When the Prius Plugin is running in hybrid mode (after the plugin battery is empty etc.), the efficiency follows a similar path -- slower is better all the way down to 15 mph which gives 104 mpg vs 64 mpg at 60 mph. This is probably true for hybrids which use a system that is similar to the Toyota system whereas conventional cars get worse mpg overall at slower speeds although I haven't seen speed-based efficiency curves that are typical for them.
Control your speed with the accelerator pedal (not with brake). The slower you drive, the easier you can control your speed (especially with electric motor). That's the route to your highest efficiency, boosting your actual EV miles.
In my PiP driving experience, the following seem to be the only significant factors in maximizing EV range: 1) Speed (most important factor, around 15 mph is best) 2) Temperature (not sure what ideal is, but generally warmer is better) 3) Terrain (flat is best) 4) Lack of having to use brake or regeneration
.... it's somewhere in the very low 30mph range ... below that, parasitic loss begins to offset mpg low speed gains.
Thank you all for the suggestions. I guess for the next gen prius, Toyota should try to make the motor to be most efficient in the 30-45mph because that is where most US city driving occurs but I guess for other markets 15mph works the best. 15mph in US is probably doing laps around the neighborhood blocks just to see Prius doing the EV miles.
it's probably not gonna get a whole lot more efficient, but it will likely have more range, and if you want even more, there are several other viable options.
I thought wishes were free, arent they? Personally Prius works for me, Volt is a 4 seater, Ford, not so sure about its reliability yet. I don't swim in enough cash to afford a weekday and a weekend ride (also I am unlikely to jump on the next PIP, I run my car to death by old age (till date it has been the cars', someday mine).
