I saw this contained in one of the posts and need some clarification

[Amyshubby]

I'm not sure which post it was contained in (I was looking at work and didn't have time to ask a question about it) and I can't find it now, so I am asking the question in a seperate thread.

Someone wrote that you don't really want to see the battery go green because it means you are not getting the best use of your Prius. It's 1AM here and I am paraphrasing, but I think that was the gist of it.

I see my battery go green constantly. My commute consists of a five minute ride to the expressway, a 45 minute ride on the expressway (used to be an hour and 15, thank you HOV stickers!) and a ten minute ride to my office from the exit. I am green on and off throughout the entire trip.

I am averaging 48MPG so I don't think I'm doing anything drastically wrong, but if I am I would like to know.

[daniel]

Don't worry about it. You don't want to try to force your battery to go green, but the computer is smart enough to keep the battery working properly. Long downhills will charge up your battery to the point it can no longer take any more charge, but there's nothing you can do about that. Also, cold weather will make the engine run more and charge up your battery, which also is not good, but there's nothing you can do about that. The EPA gives the Prius a highway rating of 50 or 51 mpg, so your mostly-highway 48 mpg is right in the ballpark. You're doing fine. You'd improve your mileage by taking surface roads instead, but that would double your commute time, and if quality of life matters to you, then squeezing out a few extra mpg is not worth it.

[kdmorse]

)*) Warning! Poster is currently under the influence of prescription medication. Coherent sentences not guaranteed, especially with the LCD bending back and forth on it's own...

If your current driving patterns result in a almost always green battery, that's not a bad thing. It means there's always plenty of electricity available for the HSD whenever it needs it.

However, once highly charged, the system can't put *more* energy in (such as from even more regenerative breaking), it has to just throw it away. In essence, you're throwing some potentially extra free energy away. You've got the potential to get a bit more ahead of the game if one way or another you can learn to use the Bat more.

One way is mastering battery only acceleration and gliding where possible. Remove your foot from the pedal, then press just hard enough to get arrows out of the Bat, but not hard enough to engage the engine.

One way is to not regenerate so much. Coming up to a stop at 45mph and breaking heavily does dump a lot into the battery - but keep in mind, you probably spent a good deal of gas jumping up to 45mph. If instead of breaking harshly, you coasted up to the red light more gently, you wouldn't cycle so much energy from gas to electric in the start -> stop cycles.

Finally, you may be a prime candidate for a EV switch. The EV switch tells the system to favor the Bat over the engine where practical. So - you start you car, flip on EV, and can drive on battery only (bypassing the normal engine warm up), until you hit a road demanding gas acceleration, at which point the engine kicks in. Then, when you get to your destination, you can flip on EV mode and battery along to your parking space. End result, deliberate preferred use of the battery and the beginning end end of each trip, using up more of the excess electricity in the bat.

In some situations it's nearly unavoidable - you're going to see a lot of green. Best you can do is try to find ways to use it.

-Ken

[ghostofjk]

Without having seen the post to which you refer, daniel is correct: don't STRIVE to "fill up" the battery, but don't sweat it, either.

I'm an '06 owner who has also had an '01, '02 and currently also have an '04. I SWEAR the '06 gets greened up noticeably quicker than any predecessor. Toyota has done some tweaking to make the regenerative system more efficient, I believe. Any others here who have also owned previous models, and agree (or not)?

[daniel]

I disagree with most of the following. I interpolate my comments in red: (I.e., red is me, not kdmorse.)

<div class='quotetop'>QUOTE(kdmorse @ Apr 25 2006, 12:23 AM) [snapback]244756[/snapback]</div>

If your current driving patterns result in a almost always green battery, that's not a bad thing. It means there's always plenty of electricity available for the HSD whenever it needs it.

Agreed.

However, once highly charged, the system can't put *more* energy in (such as from even more regenerative breaking), it has to just throw it away. In essence, you're throwing some potentially extra free energy away. You've got the potential to get a bit more ahead of the game if one way or another you can learn to use the Bat more.

Disagree: No energy is being thrown away until the battery is so full that it starts spinning the engine just to dump energy. What actually happens is that the engine burns a bit less gas and the system draws a bit of current off the battery to give a boost via MG2.

One way is mastering battery only acceleration and gliding where possible. Remove your foot from the pedal, then press just hard enough to get arrows out of the Bat, but not hard enough to engage the engine.

This is good when the battery is green, but will not work above 42 mph. Remember that Anyshubby is driving mostly on the highway.

One way is to not regenerate so much. Coming up to a stop at 45mph and breaking heavily does dump a lot into the battery - but keep in mind, you probably spent a good deal of gas jumping up to 45mph. If instead of breaking harshly, you coasted up to the red light more gently, you wouldn't cycle so much energy from gas to electric in the start -> stop cycles.

Quick starts and quick stops are probably a bad idea, but again, Anyshubby is driving mostly on the highway.

Finally, you may be a prime candidate for a EV switch. The EV switch tells the system to favor the Bat over the engine where practical. So - you start you car, flip on EV, and can drive on battery only (bypassing the normal engine warm up), until you hit a road demanding gas acceleration, at which point the engine kicks in. Then, when you get to your destination, you can flip on EV mode and battery along to your parking space. End result, deliberate preferred use of the battery and the beginning end end of each trip, using up more of the excess electricity in the bat.

Bottom line is 48 mpg is very good on the highway. Rather than obsess about the green battery icon, and speculate that it's lowering efficiency, I recommend looking at the end result, which is very good in this case. It's a little below EPA, but most of us are below EPA most of the time. Anyshubby is doing it right. Green battery icon is not a problem.

The EV switch is fun, though, and would give you a "free" half-mile at the end, with the battery being recharged at the next cold start, when the engine will be running anyway to warm itself and the exhaust system. It will also let you creep silently through parking lots and scare the pedestrians.

-Ken
[/b]

[EricGo]

I can imagine driving habits that would charge up the battery in city driving, but not on the flat LIE.

More info, Amy ?

[Amyshubby]

Thanks for your input everyone.

Just for some clarification, this is a 2006 Prius (I will update my signature to include that info when I get a chance).

I am definitely not forcing the battery to go green.

I am driving on flat roads about 99% of the time.

I use the pulse and glide method as much as possible, but since I am usually on the expressway it is more out of habit. I tend to pulse and glide rather then maintain a set speed so if I am going 70, I will let the speed go down to 67 then slowly speed up to 70 again, then repeat the process. Looking at the screen, it seems that I can speed up in slow amounts without engaging the ICE (not for long periods of time).

I don't do any hard stops. I am very easy on my brakes. I always anticipate the red lights and the traffic ahead. I have never had brakes last less then 50,000 miles (ok, driving the expressway helps ). I find that I am anticipating things even more with the Prius. Based on the regenerative braking, I am expecting these brakes to last over 75,000 miles.

I also try not to do any hard acceleration on the local roads if there is no car around me and I'm not in a rush. I try to drive off the battery as much as possible (love the stealth mode).

Also, for purposes of TOTAL disclosure- my name isn't Amy, it's Scott. Amy is my wife. The first chat group I joined related to expecting parents and most of the posting was done by women. I didn't want to deceive anyone so I used the name Amyshubby and liked it so much I kept it for all my chat groups.

[EricGo]

Scott,

OK, this is making more sense. For an experiment, would you consider driving the LIE on cruise, and see what FE and battery SOC you get ?

[hobbit]

If you come screaming into an exit ramp at high speed and brake
fairly heavily through the whole way down off the expressway, you
will go a long way toward filling the battery. Don't do that. Let
your speed drift down more slowly and hit the ramp at maybe 45-ish,
and use as much gentle but sufficient braking to bring you nicely to
a stop at the end. You'll still capture a fair amount of regen from
that but you won't have spent the extra gas on *maintaining* 70 right
up to the point where you had to suddenly start slowing.
.
Oh, and the guy riding your butt while you do this can just deal.
You're in the right-hand land with your signal on, he can just
go around. Maybe he'll learn something from watching you.
.
_H*

[jbarnhart]

I could be wrong about this (I frequently am) but I think the long gentle slowing will result in MORE greening of the battery, not less. My feeling is that hammering the brakes causes the car to slow down at a rate greater than the battery can recharge, so the car uses some mechanical braking to scrub off the extra speed. I always get greener when I drive gently! (Battery included.)