Battery not fully utilized during uphill climb?

Not really,it is software set. I was surprised to find the Prius charging the battery during uphill climbs as well. The Insight with IMA would use the battery a lot while climbing, until it hit a safety low level, then disconnect. Then charge the battery up on the way down the hill. The Prius charges it while going up hill then shuts off the engine for the coast down. They both get the same MPG doing this . Actually the Prius does a little better . go figure.....

 

That's the advantage of a FULL hybrid over an ASSIST.

In other words, having a second motor and power-split-device available allows electricity to come directly from the engine rather than always being dependent upon the the battery-pack.

It's an optimation that provides an efficiency benefit overall. It's better for battery-pack longevity as well.
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Okay, so let me ask you this. Every day I go to work, there is a stretch of road that I can run 35mph on using only the battery. Its long enough that the gauge gets down to like 2 bars or so from being 3/4 full or higher.

I usually am excited that I hit this stretch b/c I make up a lot of mpg gain on it. But I am socking the battery.

Should I NOT be doing this?

 

Don't worry about it, just drive, the car's software will sort it out. Take your eyes off the stupid gauges and keep them on the road.

 

I would not worry about it. There is another school of thought that says if a battery is well exercised it lasts longer. In my case using my battery up daily in a 1000 ft hill climb and recharging it the next morning on the downhill run still let the battery go 180,000 miles before replacing. Those that just sit die quick. This was with the first Insight with plastic sleeves holding the batteries not the aluminum tubes the Prius uses for better cooling. So I do not know if this issue is settled.

 

You are not "socking" the battery, but you are not necessarily helping your mileage either. The displayed mileage will go up, because you are borrowing energy from the battery, and that energy is not used in the mileage calculation. It's just like buying things with your credit card: your short term standard of living goes up, but eventually you have to pay it back, with interest.

Battery power is like taking a loan. The inherent losses in using a battery are the interest. Sometimes borrowing money makes sense, but you don't want to do it unnecessarily. Likewise running on the battery. Without more information, I can't say whether your EV stretch helps or hurts mileage.

Tom

 

What is your definition of "hill"?

My battery drains every time I go up a "hill" of 1500+ veritcal feet. Mountain passes always drain it then charge it, it is normal.

Toyota has taken all the necessary precautions. Just drive it and as the singing fish says, "Don't worry, be happy".

 

Is that with your throttle foot to the floor? If not, please try it and see what happens.

 

What more information would you need? I'm a little confused as I thought that using the battery on a 35mph road and not burning gas was sorta the whole point of having a hybrid?

Please don't take that as a wise crack - I truly don't understand.

 

How is everyone able to get his much energy out of their battery. ????

I have tried to put my Prius in EV mode just after starting....it's ice cold...the ICE starts...nothing I can do about that.

If I try to select EV mode it normally tells me that it's unavailable. If I do get it into EV mode.....it's not for long, until I reach 10 MPH....

I have gotten it in EV mode where I can reach 15-20 MPH, but the minute the Prius sees a hill.....it's back to ICE power

I have no idea how you people are getting your SOC down to 2-3 bars.

 

Using the battery to "glide" is the most efficient use (other than just not driving )

So propel yourself briskly to speed + some, then take your foot off. Reapply with your big toe so that the energy screen shows no movement. This means your car is moving, your engine is off, and a small drain on the battery is keeping it moving. The point of a hybrid is to only run the engine when it is needed. Not needed when you are stopped. So it shuts off. Your car is still "on" but the engine isnt. In a normal car you can do the same thing, but everything shuts off. An extreme hypermiller technique with a normal car, is to do exactly the same thing. Get up to speed, then turn the car off, and on without starting so the car is on but the engine is off. When you need to get moving again or speed up you start the engine or pop the clutch. Really inconvenient and extremely unsafe. The battery is your buffer against this and does it automatically to attain great mileage. By finessing it, you can get awesome mileage.

Prius is a hybrid, not an EV. When you need power, the battery goes down. So drive normal. Floor it onto an interstate and see the battery drain. This car does not like to be driven by a 200yr old grandma.

 

It's not the whole point of having a hybrid. All the energy comes from gasoline. A smallish engine is used in a high power, low RPM mode as often as possible for low fuel consumption (Atkinson Cycle). The Electrical components are used for three things: 1) for transient acceleration until the computer can increase RPM for the requested power; 2) to recapture energy with regenerative braking; 3) to provide on/off cycling of the ICE at lower speeds where the ICE would be inefficient just moving the car. In the last situation, the EV mode operates the car for a short distance and then the ICE moves the car AND recharges the HVB. The charging load can exceed the power necessary to move the car. The ICE is therefore loaded to a more efficient power level when it's running. The EV mode at higher speeds is less efficient than the ICE mode because of the generating/charging/discharging/motor losses. You also DON'T want a bigger, heavier, more costly HVB. It needs only to be big enough to satisfy the first 2 requirements. It is then big enough to satisfy the 3 rd.

 

Lot of information here (thank you all), so let me break it down to see if I understand. This is in no particular order, pls. correct me where I'm wrong.

A. Its better to briskly accelerate and than coast / feather the pedal to maintain speed.

B. Conversely, accelerating like Grandma by keeping your car in the Eco band is not as good

C. What I was doing on the 30-45 mph roads was:
1. Acclerating like Grandma in the ECO band
2. Once up to speed, taking my foot off the pedal, than re-applying lightly just keeping the Eco gauge to the left of the middle hashmark - thus running solely on battery
3. This was not the best use of my car - from what I understand I should drive it like any other car, get it to speed, and than coast/pulse the pedal as needed. Pulsing not being reserved to the left of the center hashmark.

This all seems completely different than how I read the manual ... am I out in left field here?

 

Using the battery is always a net loss. Going back to the money example, every time you use the battery you are borrowing, and then you have to pay it back with interest. For the best mileage, you try to *not* use the battery.

Perhaps we should step back and state something that should be obvious, but sometimes gets missed by new Prius owners: The Prius is not a plug-in vehicle. The Prius is not an electrically powered car. The Prius is a *gas* powered car that uses a battery to temporarily store energy, much like a big flywheel. Every bit of power in that battery came from burning gas, and when you take it back out again you don't get as much as if you had used the gas directly. The gas engine has to charge up the battery; spin up the flywheel, so to speak.

So, the obvious next question is why have a hybrid; why bother with the battery and those electric motors if charging the battery and using it wastes energy? The answer is that in some situations the gas engine is even more inefficient. For example, idling is a complete waste of gas. Creeping in traffic with an idling engine is very inefficient. Having a big gas engine just for passing and merging is inefficient. The hybrid system lets you avoid these big gas wasters, plus you get regenerative braking as a bonus.

The hybrid system helps, but only when the gas engine would be inefficient. Generally the control system does a pretty good job sorting out when to use which form of propulsion, but don't fool yourself into thinking you are getting great mileage when you are running on electric; you aren't.

If you really want to squeeze out the last bit of efficiency from your Prius, try to drive it like it doesn't have a battery. Use the momentum of the car to store energy instead of storing it in the battery. This is idea behind "pulse and glide".

Summing it all up, don't try to use electric. Don't sweat it when the Prius decides to do it on its own, but don't go out of your way for it either.

Tom

 

Tom, I agree with the 'loan' analogy if the car is in Kansas, but this is a simplistic viewpoint often expressed by PC posts. The intangible is whether you can gain back the electricity used using terrain--i.e. if there is a subsequent downhill in which the vehicle becomes an 'electric-gravity hybrid'. In that case, the SOC isn't 'borrowed' because the ICE won't be recharging the battery.

 

Correct. If the car had some way to know the topography it could automatically take advantage of this sort of situation. Unfortunately it doesn't, so it has to assume that all driving is steady state. Not all up-hills terminate in a down-hill. The control system doesn't know if you are climbing a short ridge, or perhaps the continental divide.

Incidentally, there is patent out for topographic GPS enhanced route optimization, so maybe your next Prius will be able to make a smart decision about SoC and hill climbing.

Also, regeneration on a downhill is only necessary when you need to slow down. Most normal downgrades at speed still require power to keep the car moving fast enough. This happens even in the mountains on 6% highway grades. At highway speeds you still need to add power to overcome air resistance.

Tom

 

I believe this is another difference between your GenII and OP's GenIII.

 

I disagree. I live in the Rockies and I watch the battery being recharged on the downhills with the vehicle in CC. It charges really fast when in "B."
The fact is that the Prius has very low wind resistance and low rolling resistance - that's part of the package.