EV mode is wasteful / less efficient on the highway - Misconception

Illinibird · Sep 23, 2022

michaeljeff said:
It’s actually pretty simple. The 42 miles estimated from EV applies to low average speeds. If your average speed is 70+ then you might only get 30 miles on a charge. If you travel all low speeds, you might get 50 miles on a charge.

The efficiency is the same for gasoline, the faster you travel, the lower mpg you get.

This is exactly the question I was going to pose. On a full charge my EV range is only 35 miles and I thought maybe something was wrong. Now I think I understand that the GOM (guess-o-meter) says 35 miles because we have used the EV mode mostly at highway speeds so far. My assumption then is if we had used the EV mode mostly around town, the GOM would say the range is closer to the 44 miles which is advertised on the window sticker. Am I correct in this assumption as per the above post?

NoelinColorado · Sep 23, 2022

Illinibird said:
My assumption then is if we had used the EV mode mostly around town, the GOM would say the range is closer to the 44 miles which is advertised on the window sticker. Am I correct in this assumption as per the above post?

We normally use EV mode for all local driving which will involve freeways as well and currently the GOM is at 55. What I notice is that once you get up to freeway speeds the amount of energy used can be quite low, so we never hesitate to stay in EV mode on freeways--except when on "trips" (i.e., when we know we will exceed EV range in which case we START in HV mode and stay there). Since new we have never reset the miles per indicator so our actual miles/kWh is at 3.4 currently, but I don't know how cumulative that is. Whenever we let the ICE run we always let it FULLY warm up.

wscan · Sep 23, 2022

You are pretty much correct in your assumptions. Your car is new and the GOM starts with a low EV estimate. You will probably see some increase in the GOM after a few weeks, assuming that you drive at 70 or below. If you are a high speed driver, the range probably will not increase much.

med2484 · Sep 23, 2022

Illinibird said:
This is exactly the question I was going to pose. On a full charge my EV range is only 35 miles and I thought maybe something was wrong. Now I think I understand that the GOM (guess-o-meter) says 35 miles because we have used the EV mode mostly at highway speeds so far. My assumption then is if we had used the EV mode mostly around town, the GOM would say the range is closer to the 44 miles which is advertised on the window sticker. Am I correct in this assumption as per the above post?

Yes, but also it will depend on driving style, hills, outside temperature, etc. The GOM is based on whatever conditions have been recently, so you'll see a fair bit of variation over time. In spring/fall when driving around town we've gotten ours to display a range of 54 miles. In winter, as low as 38. We've recently moved and spend a lot more of the commute on the highway, and it hasn't made a huge impact on the GOM range - a drop of maybe 2 miles - but we aren't accelerating super quickly and mostly drive at a steady 70mph over fairly flat terrain. If you notice that the needle on the dash is spending a lot of time in the "Power" range (due to big accelerations, hills, etc), you'll see your electric range drop pretty quickly.

q445187 · Sep 23, 2022

shmoo11 said:
ICE in a hybrid setup, just like with an EV, is generally more efficient in stop and go and city driving than at highway speeds. Non-hybrid ICE powertrains are more efficient on the highway than in stop and go. AUTO EV/HV does give preference to the battery but uses the engine in cases where more power is needed, which seems to make sense.

Agree totally, what seems off to me is the idea that switching between ev/hv depending on highway or regular roads makes some kind of sense. If you're taking a trip that is long enough to deplete batteries, I think the amount of gas you use will be roughly the same no matter when you use ev/hv. If you're taking a trip that won't deplete the battery, I see no reason to use hv mode unless you're in situations where you will encounter high engine/powertrain load, in which case auto ev/hv seems like your best bet.

i would like to be able to tell the R4P that if I am under 50 mph to do ev, and anything over that do hv. To me, THAT would be “auto”. I never use auto ev/hv now, it just sucks the battery out. Our (retired) “commute” to town is 10 miles at 75mph then around 40 ish in town and then 75mph back home, we can usually do that ALL on battery. Awesome! Love this vehicle.

newrav4p · Sep 23, 2022

I set my R4P to show miles/kWh per trip. Multiplying that number by 14.5kWh for the "usable" portion of the battery yields the expected mileage range if that type of driving is done until the battery is depleted. Sometimes I get 2 miles/kWh, which comes out to around 30 miles. A few times I've seen 5 miles/kWh, which comes out to about 70 miles! The EPA rating of 42 miles assumes 3 miles/kWh.

RussC · Sep 23, 2022

I drive to work on the interstate with a full charge nearly 28 miles reaching speeds of 85 miles per hour for brief periods of time in EV and generally averaging 75 miles per hour in EV.
Looking back at my Charge Point data 10.5 kWh has been the highest and most have been 10.1 kWh charges to travel 28 miles.

28 miles / 10.5 kWh = 2.66 miles per kwh

I have 14.5 usage kwh x 2.66 = 38 miles of range averaging 75 miles per hour with a few bursts to 85 mph.

Note: This is my most inefficient usage over the last month. The average of 10.1 kWh for 28 miles averaging 75 mph is 40.1 miles of range which is pretty good considering I am averaging 75 miles per hour over 28 miles.

Winter driving in Utah (already have been through two Winters with temps in the 20’s and 30’s) the range will drop 20% or 40 miles of range to 32 miles interstate driving at 75 mph. The heat pump pulls 30 amps and you will know when it is on when you hear a loud train horn sound on occasion when first operating in EV.

My recommendation, lower the cabin temp set the defrost on the control near the right side only (don’t tough the defrost on the left gas will turn on) set seat warmer to low and if needed turn on steering wheel heater and use my invention which is a silicone kitchen cabinet bumper placed on the steering wheel heater control so you can feel to turn off and on. Toyota placed that control in a hard to see location while driving.

I also dress warm with gloves when I drive in the winter with the cabin temp set low.

Russ

RussC · Sep 23, 2022

Cheap but works

newrav4p · Sep 23, 2022

This link has some interesting power efficiency and relative range versus speed curves. Even though the curves are for Tesla, I'm guessing that the shapes of the curves are similar for R4P. Essentially, max efficiency or range is achieved somewhere around 35-40 mph. EPA numbers are usually at 55 mph, which can be anywhere from 5-15% lower than max efficiency/range. At 75 mph, the drop-off relative to 55 mph can be 15-25%.

wscan · Sep 23, 2022

RussC said:
The heat pump pulls 30 amps and you will know when it is on when you hear a loud train horn sound on occasion when first operating in EV.

The train horn issue can be fixed. There is a TSB out.

Salmon · Sep 24, 2022

I drive mostly in EV because most of my driving is short trips. When I drive 100 miles RT to my daughter's house I drive to the Highway and get up to speed in EV then switch to HV on a downhill section and leave it there until I get off the highway where I switch back to EV mode. On the return trip I do the same except I switch to EV once I am close enough to home to almost drain the usable charge. Why do I do this?
1. The ICE is needed for the trip so I would rather run it continuously than on/off/on/off.
2. EV is quieter than HV but that is only noticeable at slower speeds since road noise generally makes the ICE less noticeable.
3. This method drains the EV charge level down from MAX fairly quickly and leaves it well above MIN until I am almost home. I have heard the more the SOC stays away from the extremes the better it is for the battery.

As for what is most efficient I don't know and I doubt it makes a very big difference. But people like to argue about that so have fun. I am sure there are holes in my strategy but that's what makes the most sense to me so that's what I do.

Illinibird · Sep 24, 2022

Salmon said:
I drive mostly in EV because most of my driving is short trips. When I drive 100 miles RT to my daughter's house I drive to the Highway and get up to speed in EV then switch to HV on a downhill section and leave it there until I get off the highway where I switch back to EV mode. On the return trip I do the same except I switch to EV once I am close enough to home to almost drain the usable charge. Why do I do this?
1. The ICE is needed for the trip so I would rather run it continuously than on/off/on/off.
2. EV is quieter than HV but that is only noticeable at slower speeds since road noise generally makes the ICE less noticeable.
3. This method drains the EV charge level down from MAX fairly quickly and leaves it well above MIN until I am almost home. I have heard the more the SOC stays away from the extremes the better it is for the battery.

As for what is most efficient I don't know and I doubt it makes a very big difference. But people like to argue about that so have fun. I am sure there are holes in my strategy but that's what makes the most sense to me so that's what I do.

This is a newbie stupid question but here it goes anyway. When we drove to where we volunteer each week (about 38 miles away) the RAV4 had a 100% SOC and the drive was set to Auto E/HV. For the drive there, we used 100% EV and were on the tollway with speed limit of 70 mph. On the way home, the car started out in EV but after a mile on two the car switched to HV and remained on HV the entire high speed (70 mph) home. Our overall mileage was high but I didn’t record it. Now my question: isn’t this the way one usually runs the plug-in hybrid? If not, and many start out only in HV what button are you pushing to force HV only from the start of your trip? Is it the HV Charge button? On the EV button it either is EV or Auto EV/HV correct? Does the HV Chg button change with the number of presses from HV Charge to just HV? I know these are probably dumb questions and I should know but I’m really unsure how you force HV mode and whether using Auto EV/HV isn’t the way the car is intended to be driven on long trips. It eventually would run on total HV once the SOC on the chargeable traction battery is depleted on the SOC gauge shows 0% so why “force” your car to use just HV on the highway and keep the SOC of the battery high for when you arrive at your destination where you could then switch to total EV? If you had used up all your EV charge and the car then runs in HV at your destination what harm is there in that until you have a chance to plug-in again at your destination (or overnight at a friends house or hotel on 110 volt outlet or lucky enough to find a L2 EVSE and replenish there for 4.5 hours). I’m trying to understand everybody's strategy for running the cars efficiently with the settings people use for different driving. I thought I had this figured out but after reading this thread I’m not sure that I do.

Chazz8 · Sep 24, 2022

Illinibird said:
so why “force” your car to use just HV on the highway

Not brought up in this thread … yet but here is my input from last year. See post #4; I dont utilize the 300HP as much as I thought I would or...

From post; “I (almost) always go to HV (hybrid) mode 90 second before I get to highway to warm up the ICE and get maximum power out of the system (and Owner’s manual recommends HV mode for highway driving).”

wscan · Sep 24, 2022

Illinibird said:
This is a newbie stupid question but here it goes anyway. When we drove to where we volunteer each week (about 38 miles away) the RAV4 had a 100% SOC and the drive was set to Auto E/HV. For the drive there, we used 100% EV and were on the tollway with speed limit of 70 mph. On the way home, the car started out in EV but after a mile on two the car switched to HV and remained on HV the entire high speed (70 mph) home. Our overall mileage was high but I didn’t record it. Now my question: isn’t this the way one usually runs the plug-in hybrid? If not, and many start out only in HV what button are you pushing to force HV only from the start of your trip? Is it the HV Charge button? On the EV button it either is EV or Auto EV/HV correct? Does the HV Chg button change with the number of presses from HV Charge to just HV? I know these are probably dumb questions and I should know but I’m really unsure how you force HV mode and whether using Auto EV/HV isn’t the way the car is intended to be driven on long trips. It eventually would run on total HV once the SOC on the chargeable traction battery is depleted on the SOC gauge shows 0% so why “force” your car to use just HV on the highway and keep the SOC of the battery high for when you arrive at your destination where you could then switch to total EV? If you had used up all your EV charge and the car then runs in HV at your destination what harm is there in that until you have a chance to plug-in again at your destination (or overnight at a friends house or hotel on 110 volt outlet or lucky enough to find a L2 EVSE and replenish there for 4.5 hours). I’m trying to understand everybody's strategy for running the cars efficiently with the settings people use for different driving. I thought I had this figured out but after reading this thread I’m not sure that I do.

There are two buttons that control the HV/EV mode of the car. They are located on the center console just above the ECO/Sport knob. The left button is for auto EV/HV. It switches between EV and Auto EV/HV. I never use this button. This button allows the ICE to start to supplement the EV power in higher power demand situations. The right button switches between EV and HV. When the car is started it always is in EV mode unless the traction battery is too low to support EV mode. To switch to HV, press the right button once. Press it again to go back to EV mode. By the way, if you are in EV mode and the traction battery becomes too low for EV, the car automatically switches to HV.

The debate here in this thread is whether it matters how/when the EV miles are used. There are certainly widely varying opinions. If your total trip can be done in EV, then just use EV. The manual does mention that EV is less efficient on the highway, so if the trip is long, it might be best to use HV on the highway and save EV for local driving. The nice part about EV mode is that it is very quiet.

In the questions above, you used the word Charge. The EV/HV button has a second function. If you hold the button down for a few seconds, the mode switches to Charge Mode. The goal of this mode is to use the ICE to charge the traction battery while driving to gain EV miles. In general, using gasoline to charge the traction battery is more costly than plugging the car in to charge. This mode has limited use. a couple of uses might be to gain EV miles for driving in areas that require EV-only (or charge fees for non-EV use) or charging up for camping.

Illinibird · Sep 24, 2022

wscan said:
There are two buttons that control the HV/EV mode of the car. They are located on the center console just above the ECO/Sport knob. The left button is for auto EV/HV. It switches between EV and Auto EV/HV. I never use this button. This button allows the ICE to start to supplement the EV power in higher power demand situations. The right button switches between EV and HV. When the car is started it always is in EV mode unless the traction battery is too low to support EV mode. To switch to HV, press the right button once. Press it again to go back to EV mode. By the way, if you are in EV mode and the traction battery becomes too low for EV, the car automatically switches to HV.

The debate here in this thread is whether it matters how/when the EV miles are used. There are certainly widely varying opinions. If your total trip can be done in EV, then just use EV. The manual does mention that EV is less efficient on the highway, so if the trip is long, it might be best to use HV on the highway and save EV for local driving. The nice part about EV mode is that it is very quiet.

In the questions above, you used the word Charge. The EV/HV button has a second function. If you hold the button down for a few seconds, the mode switches to Charge Mode. The goal of this mode is to use the ICE to charge the traction battery while driving to gain EV miles. In general, using gasoline to charge the traction battery is more costly than plugging the car in to charge. This mode has limited use. a couple of uses might be to gain EV miles for driving in areas that require EV-only (or charge fees for non-EV use) or charging up for camping.

THANK YOU! Excellent explanation and now I understand that the right button CAN be pressed two different ways. I thought it was just for HV Charge and now I know that's how you force HV and if you want then can press and hold for HV charge. I'm certain all of this is in the manual which I did read but was still confused a bit. I will follow the recommended procedure by Toyota for highway driving and put the car in HV mode before entering the highway. Besides it also will run the ICE engine once a week so that it does use gas and the tank won't become stale with non usage (I did put Standard-Bil in just in case).

Salmon · Sep 24, 2022

Chazz8 said:
From post; “I (almost) always go to HV (hybrid) mode 90 second before I get to highway to warm up the ICE and get maximum power out of the system (and Owner’s manual recommends HV mode for highway driving).”

This concept is the reason I get up to highway speed first with EV and wait for a downhill section to switch to HV. Downhill at highway speed puts only a small load on the ICE and gives it a chance to warm up before asking for more power. I find that trying to put it in HV mode before hitting the highway often causes it to stop and start which defeats the purpose of the warmup.

NoelinColorado · Sep 25, 2022

Illinibird said:
I will follow the recommended procedure by Toyota for highway driving and put the car in HV mode before entering the highway.

Whatever you do don't convert to HV mode on a cold engine then change to HV mode as you get on a freeway onramp! Second: there is no good argument for using HV mode just because you're on a freeway, or at freeway speeds. The amount of energy it takes to MAINTAIN freeway speeds is easily managed by the EV in fact you will notice as you get to say 70mph, then back off on the throttle to maintain 70mph,. you're well into the ECO range on the dash's left sided energy status needle indictor. The real decision point to consider is how many miles is this car use going to be this time out. If you can get out to your destination and back within the car's EV range, then stick with EV all the way. If you're going to exceed EV range, or are on a long trip, just start up in HV mode at some point when you will give the car ample miles to fully warm the ICE. For example, let's say you have a 60 mile trip planned today before return home, and your EV ranges is 50 miles. You could START in HV mode, run the first 15 miles or what have you, in HV mode, then go to EV til back home. This allows the ICE to get fully warmed up, and as long as you don't leave from the parking spot and jump onto a freeway very quickly (i.e., so the ICE hasn't had time to warm up more) this is a good practice to follow. The ideas are to: never rev up a cold ICE, and when you do employ the ICE as in HV mode, always insure it's allowed to fully warm up. This helps reduce engine oil dilution by gasoline, blows out moisture, and so forth. If we are on a long trip we will simply start up in HV mode and stay there til we return home. 80% of all our miles are in EV mode. We also commit to a practice to use HV mode (the ICE) at least once every 10 days or so to fully warmed, which varies depending on ambient temp.

wscan · Sep 25, 2022

NoelinColorado said:
Whatever you do don't convert to HV mode on a cold engine then change to HV mode as you get on a freeway onramp! Second: there is no good argument for using HV mode just because you're on a freeway, or at freeway speeds. The amount of energy it takes to MAINTAIN freeway speeds is easily managed by the EV in fact you will notice as you get to say 70mph, then back off on the throttle to maintain 70mph,. you're well into the ECO range on the dash's left sided energy status needle indictor. The real decision point to consider is how many miles is this car use going to be this time out. If you can get out to your destination and back within the car's EV range, then stick with EV all the way. If you're going to exceed EV range, or are on a long trip, just start up in HV mode at some point when you will give the car ample miles to fully warm the ICE. For example, let's say you have a 60 mile trip planned today before return home, and your EV ranges is 50 miles. You could START in HV mode, run the first 15 miles or what have you, in HV mode, then go to EV til back home. This allows the ICE to get fully warmed up, and as long as you don't leave from the parking spot and jump onto a freeway very quickly (i.e., so the ICE hasn't had time to warm up more) this is a good practice to follow. The ideas are to: never rev up a cold ICE, and when you do employ the ICE as in HV mode, always insure it's allowed to fully warm up. This helps reduce engine oil dilution by gasoline, blows out moisture, and so forth. If we are on a long trip we will simply start up in HV mode and stay there til we return home. 80% of all our miles are in EV mode. We also commit to a practice to use HV mode (the ICE) at least once every 10 days or so to fully warmed, which varies depending on ambient temp.

Note that the Prime does manage the ICE fairly well. If you switch to HV mode, the ICE starts and runs at 1300 rpm for a minute or so. Power is mostly taken from the traction battery at this time. Then the ICE rpm is increased. This is not to say that you can change to HV mode and hammer the throttle (not sure what this will do), but that ICE load and rpm are managed during initial warmup.

NoelinColorado · Sep 25, 2022

wscan said:
If you switch to HV mode, the ICE starts and runs at 1300 rpm for a minute or so....

That's why when we know we will use HV anytime on an outing we do it from the start, in the garage ;o)

wscan · Sep 25, 2022

NoelinColorado said:
That's why when we know we will use HV anytime on an outing we do it from the start, in the garage ;o)

1300 rpm is just above idle speed and normal for warming up. Even in the garage you will get 1300 rpm. My point is that the computer limits the rpm until the engine has a chance to warm up a bit so it is not dead cold and providing lots of power. You certainly do not need to wait until full operating temperature to use power from the ICE. Not many people do that in an ICE only vehicle.

EV mode is wasteful / less efficient on the highway - Misconception

Illinibird

NoelinColorado

wscan

med2484

q445187

newrav4p

RussC

RussC

newrav4p

wscan

Salmon

Illinibird

Chazz8

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Illinibird

Salmon

NoelinColorado

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NoelinColorado

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