EV mode at every stop

Trying Eco mode for one tank | PriusChat

I think the other was in the GenIII main forum.

 

According to Wayne the 15mph EV threshold is just a guideline that works very well for the GenII. Depending on circumstances you could take EV as high as 30mph if SOC is high and you are on a slight decline heading onto a highway on-ramp and don't have to worry about regenerating that energy right away.

Quoted with permission from Wayne:

My thoughts. If, however, you were to use EV Mode up to 25mph at every stop you would very likely deplete the HV battery and be required to recharge it using the ICE or by regen braking heavily which reduces gliding distance and is this less efficient in the long run.Essentially, 15mph is a good limit for around town driving.

He did mention that accelerating briskly in a Prius is NOT the most efficient method for fuel economy. It is better to accelerate easily in most cases.

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... so he could hurry into a gas station!

 

You can't deplete the battery because it won't accept EV only mode when the battery gets low. And the recharge is just the regular recharge of normal use via the engine and braking. When battery is up to high enough charge, it lets you use the EV mode. I'm getting 57.1 mpg with the AC on in this hot weather so I'm happy with the mileage using the EV only mode when it is available. It does appear to save the average MPG from going down during standing starts and can even add a tenth if you are on the edge. Once up to 25 mph (when EV kicks off) I can play with pulse glide to control mpg.

The fact that Toyota included the EV mode button means that they intended it to be used as the ultimate gas saving move, one step to the left of ECO mode. Like it's counterpart to the right PWR, both EV and PWR default to off being the two extremes of operation Toyota offers.

In fact, the EV only mode seems specifically designed for standing starts, getting car to 25 mph, an operation that would typically result in high gas consumption.

 

You mean not accelerating briskly in EV right? Accelerating to 3/4 or 7/8 of the ECO part of the HSI still stands?

 

There is no reason not to accelerte as fast as you can in EV mode since you are not using gas. Only reason for accelerating easily in ECO, Normal or PWR mode is to not engage the engine and use gasoline.

 

I believe so. That keeps RPM fairly low. I know the GenII rule of thumb was around 2200rpm max. I can't remember for the GenIII so I just use 3/4 of the Eco part of the HSI. Someone will correct me I'm sure.

 

I'm not sure this is true. Moving an object between two locations requires energy. The faster you try and move that object the more energy it requires. Thus if you accelerate easily or moderately you will use less energy than if you accelerate quickly. Does this make sense? Now just because it is electrical energy doesn't mean it is free energy. There is no free lunch here. The energy will have to be replaced by the ICE and when that happens you will suffer conversion losses. When the ICE is recharging the battery after it has been depleted you will also suffer a mpg loss because some of the ICE's energy is going into the battery instead of propelling you down the road. I've observed this quite a bit in my GenII and have started noticing it in my GenIII during testing for other driving techniques. Some of this may have changed since my GenII days so if anyone knows better feel free to correct me. I'd be more than happy to use more EV power bt something tells me this is not the most efficient way to drive.

 

Or the "free" regenerative breaking.

Well Toyota put it on the car to be used. As far as "most efficient", it likely contributes significantly to using less gas and that his how I judge the "efficiency" of my Prius.

 

I strive to not break the regenerative stuff.

But the consensus here seems to be that with the various conversion losses, the net 'free' energy recovered from regenerative braking is considerably less than half the electric energy needed to reach speed in the first place. At least on flat roads.

Only a very few drivers get the very special EV button that is equivalent to a wall plugin. The rest of us have to get most of that EV energy from the gasoline tank.

 

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If you're getting a lot of regen braking then you are doing it wrong. Remember, drive without brakes (DWB) is the first rule....

 

Wayne recommends 3/4 to maybe 7/8 on the HSI as the proper acceleration*. Whether that is 'briskly' to you, is a personal judgement. *- after getting to 16 mph on EV alone.

 

I get regen braking every time I take my foot off the gas. I think that is how Toyota designed the car. Same with the EV only button. It was put there to be used to save gasoline. If the driver thinks they are in a situation where EV only will work, Toyota provides a button for turning on EV only. The car "protects itself" by only allowing EV under certain conditions, battery charge level is adequate and speed limited to 25 mph. The driving situation that uses the most gasoline and fits those parameters is standing start to 25 mph.

Driving in the hot weather with 90% AC use, using ECO once the AC has cooled the car and EV at stops, getting 57 mpg, I'm a happy camper. I thought I'd take a big hit with summer AC use but I'm pretty sure aggressive use of the EV at standing starts is making the difference.

 

There is a big difference between what is safe for the car and what is most efficient. You need to get that distinction through your head. You very likely could be getting higher mpg. On flat ground I can get 70+mpg. 57mpg isn't all that impressive IMO. Try listening to those who know more than you do and applying those techniques. If they don't work for you then at least you can say you tried. Until you start posting 70-90mpg tanks I will continue to listen to Wayne, BestMapMan, Jason Holder, Tony, Evan, Hill and all the other folk who post such high numbers.

 

Are you saying 3/4, or 7/8, of the entire HSI or just the ECO half?

 

The Eco half.



From Hobbit's page:
HSI

 

I believe he (Wayne) is talking about the wide portion, not including regen or pwr. I do wish they had included a shot of the HSI instead of the useless shot of people's feet.

An image from Hobbit's page (you want to be in the green section when you are using the ICE):