Well, last night I got stuck in horrendous traffic on the interstate (construction had what was normally 3 lanes down to one restricted lane for a 3-mile stretch with no exits. There were also two cars stalled in that stretch, with very little shoulder, causing traffic to get even worse. Of course, the slowdown didn't become obvious until I had missed the 'last chance' exit before my own.) In that 3 miles (which took 30 minutes,) I averaged a dismal 20-30 mpg. This was with the radio and A/C off, lights on, started with 6 bars of battery. Ended with 6 bars of battery. Never got above 20 mph until right before the end (my exit was within 1/4 mile of the end of the construction, of course.) Came to a complete stop only twice, each time for less than one minute. Never accelerated fast enough that it SHOULD HAVE come out of EV mode, but it kept switching between ICE and EV, even though the battery never dropped below 3 bars. I could coax it back into EV mode, but it wouldn't stay there very long.patrickg said:So since we have poor performance at high speeds and low speeds there must be an optimal speed (or range) for stop and go in all electric mode.
I don't think you'll ever get as much back from regenerative braking as you put into it in the first place, regardless of friction etc. The generator is only rated at 21kW, which I think the battery might be able to absorb, but braking events often make more power than this so the rest is lost to the brake rotors (discs).patrickg said:Great stuff! A sort of related question... How many "cars" of regeneration (consumed from the battery) does it take to put enough energy into the motion of the vehicle to regenerate a car when stopping.
Note, however, that in order to extend battery life out to the life of the car, the electronics limit battery usage to only about half its capacity, and the EV range is even less, as the ICE will start the moment the SOC drops to 2 bars. And how often do you see 8 bars?PriusPhysics said:... If a fully charged battery holds about 1300 Wh, then this implies a maximum range of about 5 miles on a fully charged battery...
hehe.. It's like one of those little kid 'wind back' cars. You roll backward up the hill, then rocket back down, right? So going DOWN the hill, how many bars do you gain? (Hrm, I have a similar hill, maybe next time I'll try backing up it. It really threw my mom for a loop the first time I backed out of their steep driveway, she said it sounded like I was coasting, only I was coasting up hill.)Canadian Prius said:Yesterday I confirmed with my GPS that the difference in elevation between the base of the hill to my house is 204 feet. It is a steep hill, so to gain that elevation, I only have to travel about 1800 feet. I already tried backing up the hill in reverse, and there was no problem, although it used about four of the battery bars.
This is a good test for the battery because the Prius uses only the motor in reverse. I want to try it again and take more careful measurements.
Can someone help with the calculations? How much energy in Wh is being used to elevate the Prius 204 feet?
Also, by using the battery this intensively, will it cause any harm?
Thanks for any help with this.