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Discussion Starter · #1 ·
Newbie...
After driving 200 miles, parked at hotel.
For fun flipped to EV mode and drove 5 min..
After restart, said battery not charged enough...?

Q. Is there a switch to charge battery?

Thank you

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2022 XSE AWD non-tech
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As I have complained before, EV mode on a small-volume battery is fairly useless.

Usually, when you want to use EV mode, it always says "battery low"(OK), "Speed over the limit"(Fine), "EV mode unavailable"(Why)

EV mode cannot be used when you just start the engine - you cannot drive out of the garage by EV only.

EV mode cannot be used when the engine water temperature is low.

Even sometimes I saw the battery level is 8/10 the engine will still try to charge it.

The only thing you can count on is the programmed built-in EV mode, which can only be controlled by your feet.
 

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Q. Is there a switch to charge battery?
Yes, the gas pedal. ;). Seriously, there is no "switch"; those are included in plug-in vehicles. Remember this about hybrid driving: ALL energy comes from gasoline. This includes the HV battery.

EV mode is best used for VERY short driving/start up scenarios when you don't want to use gas or an unnecessary startup such as: moving it out of the garage/around the driveway, parking garage, etc.
 

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Yes, the gas pedal. ;). Seriously, there is no "switch"; those are included in plug-in vehicles. Remember this about hybrid driving: ALL energy comes from gasoline. This includes the HV battery.

EV mode is best used for VERY short driving/start up scenarios when you don't want to use gas or an unnecessary startup such as: moving it out of the garage/around the driveway, parking garage, etc.
How could you move the car out of the garage in EV-only mode? I tried but every time it says "EV unavailable" or something.
 

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EV mode cannot be used when you just start the engine - you cannot drive out of the garage by EV only.
Not true for all scenarios. Many variables such as temperature or battery SOC will force start the ICE but if those are met, then EV mode is available.

From the owners manual (page 236):
■Situations in which EV drive mode cannot be turned on It may not be possible to turn EV drive mode on in the following situations. If it cannot be turned on, a buzzer will sound and a message will be shown on the multi-information display. ●The temperature of the hybrid system is high. The vehicle has been left in the sun, driven on a hill, driven at high speeds, etc. ●The temperature of the hybrid system is low. The vehicle has been left in temperatures lower than about 32°F (0°C) for a long period of time etc. ●The gasoline engine is warming up. ●The hybrid battery (traction battery) is low. The remaining battery level indicated in the Energy monitor display is low. (P.122) ●Vehicle speed is high. ●The accelerator pedal is depressed firmly or the vehicle is on a hill etc. ●The windshield defogger is in use.

Also:

Switching to EV drive mode when the gasoline engine is cold: If the hybrid system is started while the gasoline engine is cold, the gasoline engine will start automatically after a short period of time in order to warm up. In this case, you will become unable to switch to EV drive mode. After the hybrid system has started and the “READY” indicator has illuminated, press the EV drive mode switch before the gasoline engine starts to switch to EV drive mode.
 

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Without using EV mode, I have driven in EV mode for more than 8 miles a day for the last year and a half. if you keep the fake tach gauge below the C in "eco", it won't start the ICE unless you need heat or the traction battery is low. I can drive from my warehouse all the way home without touching gas if I want to, but it is a bit slow to get to 40mph. its also hilly, up and down, so on the down parts, the traction battery really charges up.
 

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How could you move the car out of the garage in EV-only mode? I tried but every time it says "EV unavailable" or something.
If it is cool out, make sure climate control is off or turn it off as soon as the car is on before the ICE turns on. It will then be able to go into EV mode assuming there is enough traction battery charge.
 

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For fun flipped to EV mode and drove 5 min..
Do you mean you drove for 5 minutes only in EV mode ? Are you sure its all EV mode ? How fast were you running. I could never do that even if i tried. Has anyone else done this before ?
 

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Do you mean you drove for 5 minutes only in EV mode ? Are you sure its all EV mode ? How fast were you running. I could never do that even if i tried. Has anyone else done this before ?
It's possible if
1. The EV battery level is good
2. The water temperature is good
3. The speed is within 35 km/h
4. You feet is soft enough
5. There is no uphill or you will have no need to accelerate
 

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It's possible if
1. The EV battery level is good
2. The water temperature is good
3. The speed is within 35 km/h
4. You feet is soft enough
5. There is no uphill or you will have no need to accelerate
I've found here in CA when the weather is "perfect," I can easily start up and drive in EV mode until I'm out of the neighborhood. But you have to really feather the gas pedal and barely push on it. If you do, it'll fire up the gas engine. I never use the "EV mode" button, I've found it to be useless.
 

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Yes, the gas pedal. ;). Seriously, there is no "switch"; those are included in plug-in vehicles. Remember this about hybrid driving: ALL energy comes from gasoline. This includes the HV battery.

EV mode is best used for VERY short driving/start up scenarios when you don't want to use gas or an unnecessary startup such as: moving it out of the garage/around the driveway, parking garage, etc.
I would say a portion of your energy is coming from the vehicle’s captured kinetic energy when regenerative braking is occurring, and a portion is coming from recovered potential energy whenever you are coming down a grade at steady speed. Gasoline is not involved with those two energy inputs. In my mind, that’s mainly how hybrids conserve gasoline.
 

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It's possible if
1. The EV battery level is good
2. The water temperature is good
3. The speed is within 35 km/h
4. You feet is soft enough
5. There is no uphill or you will have no need to accelerate
I live in Ohio. If I drove less than 35km/h I will have Amish buggies passing me.
 

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I would say a portion of your energy is coming from the vehicle’s captured kinetic energy when regenerative braking is occurring, and a portion is coming from recovered potential energy whenever you are coming down a grade at steady speed. Gasoline is not involved with those two energy inputs. In my mind, that’s mainly how hybrids conserve gasoline.
It's true that you recoup kinetic energy when decelerating in regen mode and potential energy when traveling downhill. But you did burn gasoline to accelerate to that high speed and to climb to the top of that hill. The only primary source of energy remains the gasoline.

Hybrids indeed conserve gasoline by recovering energy in the ways you described, but there are a couple more. The electric traction helps the gas motor to avoid getting out of the optimal RPM and load range, and to reduce avoidable idling.
 

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It's true that you recoup kinetic energy when decelerating in regen mode and potential energy when traveling downhill. But you did burn gasoline to accelerate to that high speed and to climb to the top of that hill. The only primary source of energy remains the gasoline.

Hybrids indeed conserve gasoline by recovering energy in the ways you described, but there are a couple more. The electric traction helps the gas motor to avoid getting out of the optimal RPM and load range, and to reduce avoidable idling.
This, exactly, all helped in conjunction with the 41% peak brake thermal efficiency of the A25A-FXS engine in the Sienna Hybrid, which is seriously insane efficiency on a small ICE engine.

Here is the brake thermal efficiency graph of an A25A-FKS engine, which is a similar engine used on a 2018 Toyota Camry. This engine has a peak efficiency of just under 40%.
Slope Rectangle Font Parallel Terrestrial plant


The key here is to follow the power output curves, and you'll see that the above engine can stay at 39% or greater efficiency between 30 & 60 kW of output power (40 & 80 HP), IF you can maintain the engine RPM at the appropriate speed. You only have so many gears in a regular transmission, but MG1 on the TSD allows any gear ratio you desire between the engine and wheels, allowing maximum efficiency to be obtained until you exceed the speed at which the power requirements pull you to the right and the efficiency starts dropping. On the other hand, in addition to avoiding idle losses (which stop/start can avoid on a non-hybrid), for slow speeds you can simply run at a high enough speed to get max efficiency, pack the extra power into the battery, then shut the engine off. This is why hybrids cycle the engine on and off at low speed driving.

At highway driving, the MPG the hybrid Sienna obtains is due to that massive 41% peak thermal efficiency. For comparison, here's some thermal efficiencies of other engines. Note that the 2007 Camry engine had a thermal efficiency of only 34%!
Ecoregion Green Organism Urban design Slope


I suspect the 2GR-FE engine so many of us previous gen owner's have is likely close to the 34% mark. Maybe call it 32% since it's bigger than the 2.4 L Camry engine above. If we could put in a 41% efficient engine, and you got 24 MPG at some given speed with the 2GR-FE assuming 32% efficiency, you'd get almost 31 MPG at the same speed with that 41% efficient engine.

To summarize, hybrids increase fuel economy by recovering potential energy when going down hills or when braking, instead of throwing that away, and running the engine at an efficient output and shutting it off and using the battery when it can't maintain a steady state efficient output. The Toyota HSD in particular increases fuel economy further by allowing any engine RPM for a given load to lock onto that maximum efficiency point. And the Sienna hybrid in particular further increases overall efficiency, including highway efficiency (where in general hybrids have little to no advantage) by using an incredibly efficient engine compared to most engines that have been used in previous Siennas. There's other little bits that help like not having the AC, water pump, and alternator driven off the engine, improved aerodynamics, etc, but the biggest boost is that engine.

I write this as I'm listening to Kelly: More Than My Share of It All by Clarence Johnson, who talked about driving out to California from Michigan to look for jobs with a friend from college in the late 1920's and installing a valve so they could lean out the engine while cruising to get more MPG, and they did...they got about 3 MPG on that trip. 😲
 

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It's true that you recoup kinetic energy when decelerating in regen mode and potential energy when traveling downhill. But you did burn gasoline to accelerate to that high speed and to climb to the top of that hill. The only primary source of energy remains the gasoline.

Hybrids indeed conserve gasoline by recovering energy in the ways you described, but there are a couple more. The electric traction helps the gas motor to avoid getting out of the optimal RPM and load range, and to reduce avoidable idling.
Yes…valid points. The reduced idling and operating the engine in its high efficiency band also contribute to fuel conservation.
 

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Gasoline is not involved with those two energy inputs. In my mind, that’s mainly how hybrids conserve gasoline.
Both of those scenarios require the vehicle to FIRST get up to speed and/or climb a grade. In a hybrid, that can be only accomplished by the ICE burning gas.

Adding a plug, larger battery, and grid charging a PHEV (plug in hybrid vehicle) is what changes the gas consumption game..... drastically.
 

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I use the EV Mode all the time (in Canada) and find it pretty useful:
a) I have left the van on my driveway during the day and want to park it in the garage at night
b) Backing out of the garage to load up the van (and it's warm outside)
c) When leaving a parking lot with all the stop and go
d) Low speed zones (example: schools) where I will be slowing / stopping frequently

To answer the original question, there is no way to forcefully charge it. The engine, brakes and coasting charge it.


I do wish there was more capability with the hybrid system. There seems to be so much potential here if we could just get an increase to the battery life, like if we could add an additional battery pack or something. I know it's not going to be an upgrade, but perhaps in the near future the Sienna will get the lithium ion batteries and more charging capacity.
 

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I use the EV Mode all the time (in Canada) and find it pretty useful:
a) I have left the van on my driveway during the day and want to park it in the garage at night
b) Backing out of the garage to load up the van (and it's warm outside)
c) When leaving a parking lot with all the stop and go
d) Low speed zones (example: schools) where I will be slowing / stopping frequently

To answer the original question, there is no way to forcefully charge it. The engine, brakes and coasting charge it.

I do wish there was more capability with the hybrid system. There seems to be so much potential here if we could just get an increase to the battery life, like if we could add an additional battery pack or something. I know it's not going to be an upgrade, but perhaps in the near future the Sienna will get the lithium ion batteries and more charging capacity.
I think even the ability to top up the traction battery via plug-in would help a bit. I wish that had been an option.
 
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