EV On/Off Charge Depletion Miles and Control Not Making Much Sense

Rebooting the estimate involves removing the negative cable from the 12V battery for a short period of time. This makes the computer forget about all past performance and resets it to the factory default. It also resets all of your radio presets, and may reset a few other things. Doing it gives you a false sense of EV range, or at least a false sense of confidence in the EV range estimate.

I don't think this can be said enough: the estimate is just an estimate of EV range based on past performance. What we don't know is how far back the computer looks to get an estimate. Is it the last X number of miles? The last Y number of charges? The average amperage being pulled from the battery for the last Z number of trips? How much regen did those trips produce? Are regen miles treated as EV miles? If you have the engine on, but are in EV mode, are those miles counted? I'm sure Toyota knows just how they compute it, but they're not telling us since it's proprietary information.

The important thing at the end of the day (or rather, the tank) is your overall gas mileage. The higher it is, the better. Whether that happens because you drove a lot of EV-only miles, or you blended on the freeway at 65+ MPH, it doesn't really matter, just that it's up.

 

I have seen my EV miles drop and then come back up when switching from EV to HV mode. However, I'm willing to concede that the full charge EV miles may not come back. I deliberately started out in HV mode this morning, my EV miles did drop a fair amount, and never quite came back up to the level when I started out.

However, I have frequently left work in EV mode, traveled for a couple of miles, gotten on the freeway, switched to HV mode, continued to watch my EV miles drop until the car was warmed up, and after about 10 or 15 minutes, watched the EV miles climb back up to the same level as when I got on the freeway. Now, this is usually in stop-n-go traffic, so there's a lot of regen going on, which may be confusing the issue (or my conclusions). I'll have to pay more attention to what conditions this seems to be happening in.

 

My estimate EV was pretty consistent all summer long, but since taking a long trip, the temperatures getting colder, and my lead footed husband driving the car, it has decreased almost a mile and seem to be decreasing more as temps are getting colder. So a couple of days ago I did a little experiment. When it was about 60 degrees out, on full charge, I turned the display off and the fan off. I drove under 45, keeping the HSI low and watched my actual miles. I had to stop a few times to let traffic pass but accreted slowly. Also, since we have a number of hills, I went up gently and glided down. After depleting the EV, my actual EV miles were 14.2. This assured me that the temps and lead footed hubby are probably to blame for lower EV estimates and nothing is wrong with the car.

To learn how to drive the car, watch the hybrid monitor. Compare the miles driven with what is left and how long it takes to deplete the miles. I was really surprised to find how much a steep hill can deplete the EV. Also gliding down gentle slopes add or preserve EV. Long stops, even in drive through windows or car washes also can drain. But like mentioned by devprius, it's the total mpg that count in the end. Through watching your gauges, you'll learn the routes your car likes and places that you can plug in around your route that really helps your total mpg. I can get pretty obsessed, my hubby can care less, but it's been a total blast for me to drive and the gas I am saving is making my payments. Can't ask for more.

 

Honestly, I actually feel like Toyota should have eliminated this number from the display altogether. It makes sense in a pure EV like the Leaf or Tesla because the amount of charge left will have a direct impact on the route you take and whether you charge or not. But on the PHV, the only thing that matters is a) when it's full and b) when it's about to run out, so that if you're close to home/charger, you can try to drive a little gentler to prevent the ICE from kicking on right before your trip ends.
remember, this car gets 50+ mpg in gasoline mode. That's 1/50th of a gallon per mile. The difference between 10 and 15 miles of EV range is 0.1 gallon. There's no point in wasting even a second of your life debating why you're seeing one number vs. the other – both in terms of environmental and financial impacts.
Anyway, just drive the car. It's pretty awesome.

I mean, for most of their history, gasoline cars had just simple analog fuel level gauges without any "distance to empty" estimates and people seemed to get by just fine with that

 

Nope, no closing of thread! A lot of theories so far, but nothing provable. I think of rebooting as a new beginning. So right now, my HSI consumption shows 437 mpg for today's trip. Ratios are: EV 93% and HV 7 %. Rebooting and the battery disconnect proved very useful on my 2005 Prius, I expect the same with the PIP.

 

Susan....I did not mean to come off this way...sorry bout that.

In my sig image, you can see im averaging 125mpg for nearly 1000 miles, For me to achieve this I have to drive accordingly, and also have an approx EV ratio of 50/50. If you can use EV 50% of the time, you will get mileage around 125mpg when driven like a prius should be. Not like every other driver out there with jack rabbit starts and quick stops at lights. Learning to brake slowly and evenly, allowing for max regen is just as important as slow starts and very even acceleration.

I always tell people,....reset trip A in morning....leave the house and try a 30 mph drive(using google maps) for the entire drive, watch your HSI the entire way, keeping it at or under 20%. If you do this, you will see 15miles on your trip A. Do this enough and your ESTIMATE will increase each day. That IMO is COMMON SENSE.(no offense)



Now, Im going to attach A picture from my SCREEN....this is where my EV RANGE has increased to after about a week of me hypermiling in EV mode. 14.1EV ESTIMATE(when fully charged in AM)



Now the last 3 weeks I have had to travel alittle further, and have not had the luxury of going slow due to having to take roads/route that include a 55mph and 45 mph.....Because of this, my EV range the last couple weeks has gone down slightly, its now down to 13.7 in the AM after charge.

The moral here, is the same as car computers have worked for many years when calculating MPG. They take your MPG each and every moment, and they continue to AVERAGE them in forever..... So the fact I drive 6 weeks getting approx 15 EV miles(actual) means the car will remember how many times, how long, i kept getting those great EV miles. Now i only drove the car for 10EV miles for a couple weeks total, so that is less then the higher range. In other words, if i drive mostly getting great ev miles, the crummy trips where i have to accelerate faster wont mean as much overall. Its just math, and averaging.

The reason many in this thread are getting alittle short with you...is that you dont seem to read what we are telling you, its like you want a magical answer that does not exist.

also, FYI....each car comes preset from factory at 13.9 , at least that seems to be the most common INITIAL EV RANGE when new. Some guys have gone up, most have gone down.....all relative to your HSI, its like a tachometer sorta(not really) the higher HSI is, the more fuel/battery you use. I say this is common sense. (again no offense to you)

Dan

 

other than this thread and social suzy, ev range hasn't confused that many people.

 

Wow, you did not read one thing i wrote(on the bold) 55mph hardly qualifies for "good EV miles"

also, FYI its the FAN not just AC. fan on/off will change your estimate, this has been talked about many many times here along with the many other EV range threads on this forum.

Dan

 

won't you have internet access? i'll be checking into a spa for some r&r.

 

This is pretty off track, but here goes anyways. This morning when I started the car, the fan was on with one bar. I turned it off immediately but then noticed that the mpg was only at 20 rather than the regular 999. When I turned the motor off, my mpg showed as 999 for that short trip. I had to reset trip A to get the 999 back rather than the by the 60 (mpg was building up pretty fast). Is the mpg also an estimate in the HSI display and if so, will the fan really effect mpg that much?

 

Regarding your last point, yes. I took delivery in Springfield with the car completely empty and drove it to Berkeley immediately after with no opportunity to charge. Due to the grades near the OR/CA border, I was able to regen about 3 miles of EV range. 2 of those were used on the highway as I continued my drive, but about 1 mile was left when I got off the freeway and allowed me to get halfway home in pure EV mode after getting off the highway.