How much energy is actually regenerated?

In the first example, slow_rr uses 0.3 miles worth of EV to go a total of two miles. In the second case, 0.2 or 0.3 miles of EV are used to go one mile. This doesn't seem right, since it would take about 1.0 miles of EV to go a mile on the level.

 

That's Arthur AndersEn. My alma mater... Long before shredders became an essential office tool, though!

 

So you regenerated while in EV and got it back up to 10 miles, but did you switch it back to HV at the bottom of the hill while it still showed 10 miles of EV range? It doesnt seem right that the car "took back" the extra 5 miles of EV you regenerated.

If you search the forum here, you'll see we used to talk about "stacking". Quite a few people, myself included, were able to regenerate in EV (while going down a hill or coming to a stop), then switch back to HV, each time "stacking" more EV range to save for later use.

 

With the big issue of "stuck throttles" in Toyotas causing accidents, they changed the control software to disable the throttle if the brake pedal is applied. If the brake pedal is being applied, you can play with the throttle all you want, and the system is just going to ignore it.

 

To me, "stacking" is just gaming the system to allow the ICE to recharge the battery and create big EV range numbers, which it normally would not want to do. Yes, I understand that if you really are good at it, you can use stacking to use the ICE where it is more efficient to generate a charge that can be used on parts of the trip where EV is more efficient, but I think that level of sophistication is beyond all but a very few drivers.

 

Yeah, I purposely didnt say about thing about whether it was more or less efficient than letting the car just do it's thing . I was merely trying to point out that because some of us have been able to stack EV range by switching between EV/HV, I found it odd that the car would "take back" what was regen'ed in EV because it "knows" it was EV range obtained through "non-conventional" methods.

 

I have always found this same behavior in my PiP. If I have a certain amount of EV miles remaining while in HV mode, I can increase the number temporarily by regenerating, but the HV mode will always use that charge up, back to the same base value. I suppose if I switched to EV mode, I could use the charge immediately, but I can't, say, be in the midst of a long trip with 5 miles to go, work it up to 8 miles, and keep those 8 miles for the end of the trip. This week I even tried stacking by switching to EV mode, then returning to HV with the new higher number of miles, but it actually ate up all the regen'ed miles plus an extra mile over what I'd been storing. So if you can stack and store, there must be another technique.

 

No, the purpose of stacking is to use regeneration to charge the battery. After you have done as much downhill as is available for regen you switch into HV, the EV miles will then stay within a 1 mile range. You can then switch into EV (ICE not running if you are below 62 mph) at the next downhill, pick up 2 or 3 more EV miles and switch back to HV and keep those miles +- 1 mile. There is, however, a limit. If the SOC is above 75% say at its maximum of 85% and you go into HV it will use up the charge to bring it back down to under 75% often as low as 70%. That's where you can lose the EV miles as you have experienced. Using this technique I can go from minimum charge (20%) to maximum charge (85%) coming down out of the mountains (its not all downhill, I have to use HV part of the time) and have 10 or more EV miles to use in the flatlands. Pretty much all that charge comes from regeneration not the ICE since you can see most of the EV miles increase when the ICE isn't even running.

 

I would only say that are some other factors coming into play with these... On the second one I am going around 45mph at the top of the hill and am braking to pull into the museum driveway at the bottom of the hill. There is a lot more kinetic energy built up to take advantage of. That does effect what I show.... In the first example there are several small hills to climb and come back down both going in and coming back out of camp. I tend to use built up energy to get up over the small hills and build up speed on the other side, braking a few times when necessary to stay within the 10mph speed limit... (the Ranger has some nasty speeches for those who speed on camp roads. LOL) It was not intended to be a "Scientific" study, just what is shown by the dashboard of the PiP. It shows about the same every time I make those trips.... Why? I do not know... They are very different places, and I just wanted to share how much regenerative braking appears to help me in these two places. YMMV

 

If it wasn't clear, I was agreeing with you. I can't seem to figure out any way to 'stack' EV range for later use once I'm in HV mode.

 

Just a thought, are you regenerating in HV or EV mode. If I am regenerating in HV mode and then change to EV mode for a second, it has always saved the regenerated power. Then I switch back to HV and the amount shown remaining in EV will stay up and not be used (except as the usual fluctuation in HV). At least that works on mine....

I realize Greg has said that doesn't work for him.... Not sure why as it appears to on mine???

 

Hmm.. I suppose that's possible.. maybe even regional differences. It would be interesting to find out.

FWIW, I checked the ECU part numbers. There are two, but 2012-2013 share the same part number (from 1/12-9/13). It looks like the 2014 ECU is a different part. I realize thats just the hardware.. but that's all I can check myself.

 

Ok, I just misunderstood your wording.

Yes, regenerating in HV mode. Switch to EV mode, say as I come upon some traffic. Switch back to HV as I move back to highway speed. It will use up all of the regenerated miles I had stacked before.

 

Just to be clear that we are comparing apples to apples here: The question is: if you go downhill in HV mode and regenerate a significant charge but not above 75% SOC, and then you toggle into EV and back to HV, will that SOC become the new "set point" for HV mode? The answer from us "old timers" with 2012-2013 PiPs is "yes". Has something changed in the 2014 software to change this behavior? Is it different if you do the regeneration while in EV mode? Note that even if the battery is depleted at the top of the hill and you cannot switch to EV mode, once you regenerate enough, EV mode will be re-enabled.