EV miles can be regenerated by PIP after EV depletion

Today I depleted the EV miles in my Prius Plug-in Hybrid before starting up a mountain, going from about 1500 feet to 6300 feet. It was HV all the way up.

Upon reaching the top, I parked for about 8 hours. When leaving, I started the PIP and only the green ECO light was lit. The ICE came on after a few seconds. I touched no buttons, but started down the hill in B. After a short time I noticed that I had 1.5 EV miles available, and the green EV light was lit alongside the green ECO light. I don't know if EV miles showed before 1.5 miles or not. As I went down the mountain, I touched no buttons, and the EV miles increased to 16.4 when I heard the ICE go very fast to burn off extra electricity, just like I used to hear most of the way down in my 2004 Prius. The EV miles increased to 16.7 at the highest when I came to the bottom of the hill.

I mention this because I thought I had read other posts saying once the EV miles are depleted and the PIP automatically goes to HV, you can't get EV miles back. I had taken the to mean "unless you plugged in." My experience is that PIP regeneration can bring back EV miles as well as plugging in.

The above was true w/the prototypes/PHV demonstrators. It was changed in the production version.

http://priuschat.com/forums/toyota-...tion-strategy-lessons-learned-prototypes.html and http://priuschat.com/forums/toyota-...s-improved-95-mpge-rating-19.html#post1473651 are posts about the change. There were others.

So you had almost 5000 foot drop, in a Gen 2, you would start using engine braking after a 600 foot drop, do you have a guess how much drop the PiP can use for Regeneration before engine braking?

Our genius Pips can regenerate in EV or HV. It also steals saved EV miles in HV! I don't think that's nice.

I also think my Pip has regenerated miles after having been seemingly depleted. I will be maybe 2 miles from home after work; I am feeling the range-anxiety building because I really want to make it home without ICE coming on; then, drat! The EV light goes out, the arrow indicates the wheels are being powered by gas engine, and the battery is now 'striped'.

Then, after a few times braking and/or taking my foot off the gas, I notice the EV light is back on, the arrow indicates my wheels are being powered by battery, BUT the battery is still striped and there is no remaining battery mileage left - estimated or otherwise.

So it seems to me that my PIP finds enough regenerated battery take me the last 1.5 or so miles home. Can it be that this car is that smart?

I enjoyed that experience for the first time back in August 2000, long before there was a plug-in model.

That's the usual Prius operation the mode commonly referred to as: STEALTH

It's when you're driving with the engine motionless using only electricity, but not actually in EV mode.

My guess is between 4000 and 4500 feet before the engine revs up. Also, this was a complete recharge of the traction battery in about 20 minutes. This is sure a lot faster than the usual 3 hours from a regular electric outlet. I hope the fast recharge doesn't hurt the battery, as I will do this often.

Should not affect it, the car is designed for mountains. You must be on top of that BIG hill outside St Bernardino by the ski resort, Bear Lake?

I just read this interview today with Satoshi Ogiso, Toyota's lead engineer the Prius liftback, v, c, and Plug-In..

source: Interview with Toyota Prius' chief engineer

I'm guessing something was lost in translation. The car is clearly designed to prevent overcharging. If too much regen, too quickly was a bad thing, I'm sure the car would protect itself.

I am just dying to go down my local hill, The Sierra Nevada Mountains. ~ 8000 Ft. !

On our Prius when I go down a large hill for maybe 2 miles or so the battery pack will
completely fill and then the car will go in to engine brake mode.

Now with the plugin Prius the battery pack would continue to fill maybe giving you an extra 1 mile
of ev range. Over time I could see where even without plugging it in you would probably
get more mpg's than the regular Prius...

oh, most definately.

Tracksyde,

Thanks for finding the article. Good Stuff.
I wish Satoshi Ogiso would allow one of his engineers to support PriusChat.

So braking down a long hill will recharge the EV battery giving you more EV range? Is that right? I own an 08 but Ive been considering buying a 12 plug in. I live in Ithaca NY. Hill climbs and decents are normal here no matter which way you are traveling.

I think it greatly depends on the topography/geography you live in and drive in on a regular basis. But, I would think that for the majority the "regular" Prius would still slightly beat a PiP simply due to less weight. This is of course only if the PiP never gets plugged in.

Did I understand correctly from Paradoxs file that during descends, it is good practice to drive in EV mode, since then, the energy recovered will be stored for later usage? In HV, the HSD will use it up to help optimize gas consumption. I am aware there is some dabate over whether this is the best thing to do...

Jan

very cool indeed...

I am somewhat confused about this whole discussion. When you go downhill, regeneration will put charge into the battery regardless of the EV/HV setting, and by judicious timing of when you press the EV/HV button, you can significantly increase the reported number of EV miles. But it's just a bookkeeping trick; if you press HV on the way up the hill and switch to EV on the way down, you burn lots of gasoline to do the climb, but you credit that to "HV". The EV/HV miles record doesn't indicate how much fuel (gasoline or electricity) was consumed on those miles. So you have some number of HV miles where you used a lot of gasoline to climb the hills, and some number of "cheap" EV miles on the downhill and flats.

If you had left it in EV, the battery would have been quickly drained on the climb (resulting in a smaller number of EV miles), and from then on you would be in HV mode, unless the downhill regenerated enough to allow the EV mode to kick in for a while.

But you consumed the same amount of gasoline either way.

That's the key.

Flying to work on the 70 mph this morning, which included my first Leaf sighting when I was in my PHV... which meant dropping the pedal to catch up to it, honk, and wave... resulted in a MPG of about 225.

Who cares that EV miles logged were low due to the high-speed travel. That efficiency in the end is what counts.