Understanding my new car

Read this thread.

And this one.

 

<div class='quotetop'>QUOTE(Vegas201 @ Jan 10 2007, 06:51 PM) [snapback]373848[/snapback]</div>

Wow, you got all the bars on the battery? I've been trying for 5 months!

Without knowing any more details, everything you described sounds fairly typical. Fuel efficiency sounds low compared to what I get, but it's affected by length of trip, weather, road & traffic conditions, etc. If it's been getting colder, that would explain decreased fuel efficiency.

Keep an eye on things, but I wouldn't worry about it too much. Just enjoy!

 

<div class='quotetop'>QUOTE(Vegas201 @ Jan 10 2007, 06:51 PM) [snapback]373848[/snapback]</div>

Median MPG on greenhybrid.com is 48 but clearly will vary with type of trip and temperature. Your average sounds low to me.

I want to reinforce what Tideland said, maybe say it another way. You need to know two things.

First, the gas engine (ICE) -- any gas engine -- is inefficient when run at very low load or very high load. The efficiency gains from the Prius come mainly from avoiding running the ICE at very low or very high load. Instead of running at light load, the car just shuts off the ICE and uses electric. Instead of running at heavy load, the car runs gas and electric together. THe high-load situation -- the Prius handles that automatically, there is nothing there for you to do or think about. The only thing for you to consider is what, if anything, to do in low-load situations. Hold that thought.

Second, the round trip of energy into and out of the battery wastes about 20% of the energy.

Put those two facts together -- the ICE is only inefficient at low load, the battery-motor combo wastes 20% of the energy input to it -- and you realize that *you only come ahead, using the electric motor, when you use it to displace what would otherwise have to be a low-engine-load situation*. So, to the extent that you want to shoot for better mileage, you want to try to use the electric alone ONLY in what would otherwise have to be a low-load situation -- cruising at speed at 35 MPH, coasting downhill, cruising a parking lot.

So the general rule is this: any time you can put the ICE under adequate load, do so. Only if you can't put an adequate load on the ICE, should you try to get all-electric propulsion.

In particular, do NOT do slow extended acceleration on electric only, to see how long you can go before the ICE kicks in. It's kind of cool, I enjoy it myself occasionally, but it wastes gas. Instead, a moderate rate of acceleration will load the ICE efficiently. The right thing to do is a 1-2-3 sequence: 1) accelerate up to speed with the ICE (exactly how fast is a matter of debate), 2) flick the gas pedal to shut off the ICE, and 3) coast under electric power for as long as conditions allow.

Bottom line is that if you just drive like the cars around you, within reason, you'll get *better* mileage than if you drive with long slow electric-only accelerations. The Prius will do that 1-2-3 on its own, driven properly. You can just help it along a little by flicking the gas pedal off when you think the timing is right -- because you can anticipate the terrain and what you intend to do, but the car can't.

Anyway, that sequence -- accelerate with the ICE, flick the gas off a second to shut down the ICE, then coast -- becomes second nature after a few weeks. And it will significantly help mileage in urban/suburban settings. I'm not sure the hard-core hypermilers would call it pulse-and-glide, but that's how I refer to it.

Regarding temperature, in cold temps, the Prius will run the ICE just to give you heat in the cabin. The real hard core among us -- just don't heat the passenger cabin, period. You're warm-blooded, wear a sweater. Others take a more moderate view, and just don't turn the heater on unless you're running the ICE anyway -- on the highway, say. Works OK here in Virginia, not sure what it would do in NV. You might at least consider waiting on the heat until you've driven 5 min, if feasible, and maybe shut off the heat at long stoplights. Otherwise, it'll idle the ICE solely to produce heat, which reduces your mileage. Real cold-climate types get block heaters.

Hope this helps.

 

<div class='quotetop'>QUOTE(Vegas201 @ Jan 10 2007, 04:51 PM) [snapback]373848[/snapback]</div>

Battery completely charged may not happen all the time for flat-landers.

This is probably not a lemon, the technology is sound.

Change your oil if you haven't already.

Is your A/C left on by chance?

Reset your MPG indicator each tank and keep track.

Add a block heater and start your car warm, drive normally.

My 07 has about the same number of miles, but primarily highway, and I'm seeing 43mpg average. Not bad for not broken in and mid-winter and ethanol fuel mixes. Engine block heater made a world of difference in comfort and mileage. Only 300W too. Let us know how it goes!

 

<div class='quotetop'>QUOTE(Vegas201 @ Jan 10 2007, 06:51 PM) [snapback]373848[/snapback]</div>

Did the dealer tell you to put it in B to use the battery? B means Brake, so don't do that, use D.

 

Climate, terrain, and technique all play their part. Check out greenhybrid.com and look for Prii in your area to see what others are experiencing. In NJ it just got cold--freezing cold (yes, I hear the snickers from the North) and my calculated tank today was 411 miles on 7.648 gallons for 53.7mpg (lifetime now 49.5mpg). I blocked the upper half of the grill, inflated the tires, drive with as little heat (usually none) as I can stand, and try to stay 45-55mph in the slow lane (speed limit 50-55mph).

Sometimes I start thinking that maybe my car isn't normal as the battery only goes down 2 bars and is regularly green. The one thing you can say about the car is that "abnormal" is normal. After 6 months and some 8700 miles I've become comfortable enough with the car to start trying what others here have recommended. Check out the threads and you'll probably find we all had the same questions. Listen to the mechanically inclined here. If a couple of them tell you there is nothing to worry about, then stop worrying. IMHO (no offense intended) it seems the mpg condition is probably due to the driver. Once I slowed down and moved to the right lane driving is less stressful and driving the Prius is fun--and you don't get to the office any later.

 

<div class='quotetop'>QUOTE(Vegas201 @ Jan 10 2007, 03:51 PM) [snapback]373848[/snapback]</div>

Your question is valid, but very complicated. I do not know how winter temps go where you are, but a desert climate, suggest OK during the day and colder at night? This car has a very small ICE (Internal Combustion Engine) that will cool off very quickly even at a stop light. Look at all the threads on radiator blockers and block heaters for people in colder and really cold climates. If it is not very cold and the terrain is flat as I expect it to be where you are you could be driving better for milage. Remember you can not do much during warm up and on short trips. The computers are programed to get the ICE into the most efficient mode possible so, not much you will do can greatly improve milage. After the ICE is all toasty and nice there is a lot you can do. The Energy display is your guide. Once the ICE is up to temp accelerate so the mpg are in the 20 mpg range or so after the first few seconds. Once up to speed back off, coast and very gently put pressure on the gas until there are no energy flow arrows on the MFD Energy display. Read around there are many tips here. You are in a better climate than I am! When was the last time you saw snow on the ground there! Good luck

 

I just posted it did not show....

 

Don't idle the car to warm it up. While it idles you get 0 MPG. The fastest way to warm up any car is to drive it, gently for the first minute or so. Get in, turn it on and go.

 

Don't do the warm up. There is a coolant thermal bottle to take care of that.

 

As soon as I get in the car, I let the motor idle for about a minute and then the tone changes. This might be an indication that the Prius is ready to go.

 

It is not. The car is "ready to go" as soon as you can shift into drive (i.e. even before the ICE comes on). There is absolutely no need to "warm up" the car. You're just wasting gas if you spend any time "warming up" the car.

 

When you see the READY light, you are good to go.

 

The tone changes 'cos the engine and catalytic converter have reached optimal temperature. You'll reach that point sooner, plus make progress to your destination, by driving it immediately after turning it ON. Both of these will improve MPGs.

 

<snip excellent explanation of those two things>

That was very very helpful. Thank you.