Watch my commute.. is this normal?

^^ nice analysis.
Starting out in the cold going uphill with a low battery SOC is a perfect recipe for a high revving, quite inefficient ICE.

 

I have relatively limited experience.
But I agree that the problem seems to be the initial state of charge on start up, NOT how The Prius is trying to deal with the low state of charge.

My Prius is relatively new, but so far in spring and summer temperatures in a 24 hour period the HV battery never seems to discharge overnight to that low of a level.

I think you need to find out why your battery is discharging nightly.

Good Luck.

 

The EV-mod might help as bit, but you've got to use it carefully. Learning about the stages of hybrid operation would also be very beneficial. http://techno-fandom.org/~hobbit/cars/five-stages.txt

However the single biggest thing you can do to improve your performance is to find out what is causing you to get down to one or two bars of SOC at the start of the trip. Like I said before, take really careful note of the SOC at the exact point when you turn the prius off at the end of the day, and then note the SOC again at the *exact point* that you boot the car the next morning.

If you find that you're actually losing the SOC *after* the Prius has made ready, then try letting it sit in "P" and idle for approx 60 seconds before driving. That's what I have to do and it definitely works for me.

BTW. Yes change the 12V battery, it can't hurt.

 

I'll say it again, try warming up the engine for 60 seconds before driving.

 

take it for a nice long drive (you might enjoy it!) and watch the battery level.

 

Jeff,

Have you changed the 12 volt yet?

I do agree that if you are doing short runs it does help to do what uart suggests. Also, it takes the Prius a good ten minutes before it is fully warmed up even on those warm summer days. By warmed up I mean where the MFD is showing a consistent 50 MPG or better on the MFD.

Glad to hear you are feeling more comfortable with the new/rebuilt traction battery.

Also, I am glad to hear you have learned about the 4 stages of the Prius. When one learns the ins and outs of the system, it tends to make it a little easier to operate the Prius to get the best MPG for the trips made. YMMV.

Ron

 

Jeff,

Chances are your battery will be Ok through the summer, but will probably let you down come this winter. Keep an eye on the voltage especially if you let the Prius set for more than a couple of days with the SKS system on. In my signature you will find a link that details how to change it out. It is a simple job and only requires a few tools and some common sense.

Thanks for the update and the reply.

Ron

 

Jeff,

Our Prius does not have a "regular commute". It is used as a transport method for two old ailing adults who are caring for one another. It goes back and forth to the doctor, grocery store, and an occasional out of town trip. Hence, a lot of our trips are short.

It wasn't until I learned about the five stages, the throttle positions which can be monitored by scan gage, tire pressure (critical for the Prius) and hypermiling that I began to actually "beat" the EPA. But I will admit that it is a challenge to "do it" on a day to day basis with the short trips.

My best advice is to try to combine your trips when possible. And when you do that, go to the furthest one away first. That will allow the Prius to fully warm up and give the best MPG.

Stage 4 is where you need to be as quickly as possible. It sounds and looks great on paper, but sometimes the conditions with a short trip just won't allow it. However, we both know that it is not impossible.

Good luck to you.

Ron

 

Hi Jeff. I see you've found the link to hybrid stages useful.

You've managed the trick of getting through "stage 1" without running the SOC down too low, and that's helping a lot. The second trick to look into, is getting out of "stage 3" once the engine is warmed up. This is the key to giving the prius good gliding manners.

Stage 3 is like the hypermilers bugbear. If you're in stage 3 and you try to start a glide from below about 34 MPH (stage 3a) then it just wont do it. In this mode it keeps the engine running indefinitely, so you just cant get a true glide. Even when the "arrows" on the display show no engine (ICE) power, you'll notice that it's still often less than 99.9MPG and the engine is still actually running. Since the engine is already running then the slightest demand for power from the accelerator will normally result in ICE providing it. Take a look at your video and you'll clearly notice this effect in the last few minutes of your journey. You've got plenty of charge (7 bars) but you just can't make full use of it because of that dammed "stage 3".

So what to do? Well there's basically only two choices (well three if you include just putting up with it, as realistically most people just do so).

1. You can try to always reach at least 35 MPH before each glide. This can of course be difficult or impossible in some cases due to traffic conditions. However I often manage it by leaving a bit of a gap to the car in front and then accelerating to 35MPH just to release the go pedal and glide.

BTW. My wife hates it and always yells at me that I'm going to rear end the car in front when I do this.
One time she asked: "What are you doing accelerating up the arse of the car in front like that?".
I replied: "I have to make 57 km/h to get the prius to stage 3b for a glide!" (with tone of voice implying this is more important than avoiding an accident).
She said: "What the heck, this is worse than the DeLorean in Back to the Future!"

OR

2. You can try to arrange a stop with the engine running. This is the cue for the Prius to transition to the holly grail of "stage 4", full hybrid mode. Unfortunately you have to be at a complete stop for 7 to 10 seconds with the engine running for this transition to occur. Most people try to arrange it at a regular traffic light stop, but some die hard hypermilers actually make a dedicated stop where they pull over just to allow this to happen.

One tip if you stop (at lights for example) from more than 34MPH (stage 3b) and therefore the engine has cut out. Is to hold the brake pedal and then tap the accelerator pedal to force the engine to come on. If the engine is warm enough it will idle for 7 to 10 seconds and then cut out, placing you into stage 4 for the remainder of the trip. (If however the engine turns off immediately then it wasn't warm enough, so unfortunate you're still in stage 2 and the procedure didn't work.)

 

My best suggestion would be for you to read the article in my signature that hobbit posted. It is lengthy, but a wealth of info is in there. I don't have the scanguage like you, so I have to rely on the MFD and the various readouts to make an educated guess. I concentrate on that subject when I cannot "glide" (above 42 MPH). There is a threshold that can be found where the Prius will read out 60 MPG and higher at times with certain accelerator positions. It seems to work best on flat surfaces. IIRC some folks call it "dead banding" ("just enough" constant accelerator to maintain speed and allowing speed to fall on uphill and pick back up on down hill) The way I find it is to accelerate to target speed, then let off accelerator just enough to see the instantaneous read out show 60 or more AND the odometer changing speed very slowly or maintaining target speed.

The trick to getting a true glide is making sure you are in "stage 4". I concentrate on allowing the engine to come to a full stop at traffic lights, stop signs and what have you. It takes a few minutes (usually ten summer time, a little longer winter time) for the ICE to fully warm up. Also, when you have a lower SOC, the ICE will try to kick in to recharge the traction battery. Sometimes it becomes a game to keep tricking the system to keep the ICE off and keep the momentum going until you can regen by slowing down and or braking at the next stop. There are times I still have to use the ICE to pick up some SOC as regen is not as efficient concerning charging of the traction battery. It's a double edged sword but if you can keep the SOC high (5 to 6 bars) and keep the ICE off by hypermiling as much as possible, you can beat the EPA average overall. Note, overall means a average of ALL trips, not just one...

EDIT: uart's post above is spot on concerning the two methods to get into "Stage 4". I utilize the second step, but at times have also done the first. The main thing is to get into "Stage 4" as quickly as you can. END OF EDIT.

I believe the correct answer is "No, switching to neutral only disengages the drive lines". When you do that the ICE will stay at whatever stage it is until the transaxle is shifted back to D, B, R, or P. If the ICE is idling and you shift to neutral, the ICE will continue to run, and the injectors will continue to feed fuel (lowering the MPG) There have been post's in the past that state shifting to R from D will cause the ICE to turn off, sometimes that works, other times it does not. Concerning the use of N (neutral): It is best NOT to use it except in a case of emergency or absolute need. When in N, the charging system for the traction battery turns off and does not maintain the normal SOC. If the SOC falls too low, the red triangle will light and the alarm will sound. There will also be a warning appear on the MFD saying to shift to P to allow battery to charge.

One tip that really helps me is to fully release the accelerator pedal then reapply enough pressure to achieve a glide state and or find that "sweet spot" that hobbit talks about. Feathering seems to be slower and more difficult to find the right position for me.

NOTE: Hobbit calls feathering what I described in the last paragraph. I describe feathering as easing on and off of the accelerator pedal. Sorry if I added any confusion in my post.

Ron