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

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.

 

)*) 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

 

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)?

 

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>

 

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

More info, Amy ?

 

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 ?

 

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*

 

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.)

 

Your brakes will probably outlast the car. They almost never get used. Have fun!

 

<div class='quotetop'>QUOTE(daniel @ Apr 24 2006, 10:07 PM) [snapback]244720[/snapback]</div>

What would be the effect of using the "B" position? Would it still charge?

 

Let me clarify: There is nothing wrong with a fully-charged (to the limit the car allows) battery. Using B will send less charge to the battery because energy is being dissipated, rather than stored; and maybe different braking styles are less efficient (though I doubt it). But energy dissipated is energy wasted. You want to maximize, not minimize regeneration. A long downhill will charge up your battey so it has no room to accept more charge, but the solution is to drive for a while in electric mode, or allow the car to draw down some of that charge (which it will on its own once the downhill is done) not to try to waste some energy.

Bottom line: don't worry about a green battery. Unless maybe you can find a route with fewer hills. But I think Amyshubby said his drive is fairly flat.

In fact, don't worry about anything that you would not see if you turned off the MFD!

 

<div class='quotetop'>QUOTE(jbarnhart @ Apr 25 2006, 04:40 PM) [snapback]245169[/snapback]</div>

This has been my experience as well. I start off every day with a nice little downhill; by riding the brakes from close to the top I always am green at the bottom; when I waited and braked harder toward the bottom of the hilll I stayed blue.

 

I can't remember the exact #s, but what I do remember is this:

Slowing from 50mph to 0 should take 20 some odd seconds for maximum regen. I boiled it down to 2 mph/sec and that's what I remember. Of course, braking going downhill affects the equation. Basically, it's feathering the brake. It requires looking ahead. In practice, I'm looking a few lights ahead to prevent shoveling too much coal, or braking too much. Probably drives the folks who race from light to light bonkers, but as someone wrote, they can just deal with it.

Someone on this forum I'm sure will be able to come up with a link to the braking/regen. efficiency data.