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Discussion Starter #1
I've noticed that the battery energy bars usually top out around 75% with 6 blue bars. Once in awhile, the blue bars change to a light green color and a 7th bar shows up, signifying around 87.5% charge. Only once have I noticed the final 8th bar showed up to signify 100% charge.
Note: usually, the majority of the time the bars are blue and the charge stays between 75% and 25%.

I talked to a classic Prius owner who said that he has not noticed this behvaior on his Prius.

Anybody have any thoughts on this?

cheers
 

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I don't think I've seen the 8th bar light up on mine, though I sometimes turn the display off at night on my way to work. It seems to stay between 5 and 7 bars all the time and as long as I never see a deep discharge, like down to 3 bars or so, I'm just going to let it keep doing it's thing.

When driving at night with the display off, the visibility with the HID lights is just super! :D
 

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I guess Toyota though that it would be cute to color-code the battery level just as a quick heads up for the driver. For example, you have green at 7 or 8 bars... "yeah! you have tons of energy"... The bars are blue from 3 to 6 bars... "things are OK, we have energy"...The bars are purpulish red on 1 to 2 bars... "ahhh, the hamsters are tired"... I guess Toyota wanted to improve every aspect possible including the monocolor 3-level battery indicator in the '01-'03 Prius. I've seen the level as low as 2 bars, and as high as full. :wink:
 

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Discussion Starter #4
Cool thanks for the green, blue, red color code info :)

My classic Prius friend said he has never noticed his Prius battery get above 75% or below 25%. I'm wandering if Toyota has changed the algorithm a bit after getting more experience with batteries?
 

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My classic Prius friend said he has never noticed his Prius battery get above 75% or below 25%. I'm wandering if Toyota has changed the algorithm a bit after getting more experience with batteries?
I should qualify that, being the person referenced.

The only time it hits "100%" is on a long downhill stretch. I've never seen it go below 25% or have the dreaded "turtle" show up.

As I understand it, in the '01-'03 models, the actual charge as related to total AH capacity of the battery is always kept between 40-80 percent. That is to say, when the energy graph shows "full" you are in fact at only 80 percent of capacity. I believe this was done to protect the battery from the possibility of reverse charging a cell.

I've also heard a rumor here that there is a higher charge state on the '01-'03 which shows the little "posts" at the top of the battery filled in. I've never seen that one.

Steve
Portland, OR
2002 Brilliant Blue
35100 miles
 

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Discussion Starter #6
OK. That agrees with my experience in the 04 Prius. I can get a full battery charge (all 8 bars) when cruising down long hills. Although, I have gotten 7 bars (in the new light green) while crusiing around town. But it immediately dropped to the usual 6 blue bars when I got up to over 50 mph.

In another thread, a European guy stated that while using the EV Button, the battery can drop to 2 red bars, in which case the engine will kick on again. I'd like to evenutally find out more about the EV Button. Maybe the 05 model might have it?

In yet another thread on the 2004 prius yahoo site, a guy traveled over a mile looking for a gas station, after his Prius had run out of gas. He said the battery dropped to 1 bar and several warning indicator lights were on. Maybe an EV button would be useful in this situation?

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Classic Prius max state of charge

I've seen the "terminals filled" state of charge indication on my classic Prius only once, after a long downhill full of tons of regen braking. At the time, I had never heard of it and was a bit surprised, but it does exist.
 

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green battery bars

Just got our Prius last week and took it for a road trip yesterday. About 350 miles from where we live - near Richmond, Va. - out to the Blue Ridge Mts. and through a corner of West Va. Wonderful car. Tho our mountains are foothills compared ot the Rockies, still there are a couple of respectable 2-3 mile 9% grades, hairpin turns, etc. on 2-lane state highways (250, 220 and 33) Car had no trouble with the climbs. Used the "B" gear coming down and that works great, like shifting down into 3rd. Anyway, to the subject at hand. At the end of long downhill grades had all 8 bars lit (green). Then when I shifted back into "D" and drove on a level or slightly downhilll grade at 55 -58 MPH I was in stealth mode, i.e., just the electric motor working. This lasted a short time until the battery bars dropped down to 6 (blue), then the ICE kicked back in.
 

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Here are details on how the Classic's (NHW11's) battery icon works. I've simplified a few things (e.g. there is hysteresis in the transitions). The source of my data is Graham's website (http://home.earthlink.net/~graham1/ and specifically http://home.earthlink.net/~graham1/Priu ... yItems.htm) in addition to my own observations.

1. There are only four bars. The posts never get filled.
2. The battery is only displayed as "empty" when its state of charge (SOC) is below about 20%. This can't happen unless you run out of gas or have some major system failure.
3. The first bar is displayed when the SOC is between 20% and 43%.
4. The second bar is displayed when the SOC is between 43% and 56%.
5. The third bar is displayed when the SOC is between 56% and 73%.
6. The final bar is displayed when the SOC is between 73% and 100%. This only happens at the bottom of long hills.
7. Under normal conditions, the battery will be maintained between 45% and 80% SOC. However, the battery icon shows the full range of possible SOCs. This means the "empty", "1/4", and "full" states will rarely be displayed. For typical driving, the SOC is maintained between 55% and 65%, so most drivers see only the "3/4" state.

I've heard that the model year 04 Prius (NHW20) has some changes to make the battery icon more meaningful: "empty" is 40%, "full" is 80%, and there are more bars, which are evenly spaced across this range. Note, I've heard the NHW20 allows the battery SOC to fall to 40% (instead of 45% in the NHW11) before it forces recharging. However, the battery icon is still just for fun, because the Prius handles all the battery maintenance, so you don't have to worry about it.

Douglas (2002 Silver, Wisconsin)
 

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The lowest I've ever seen on my '04 was 4 bars, on one occasion, very briefly. It's almost always on 6 or 7 bars, less frequently on 5 bars, but only when everything is good and warmed up during a somewhat longer-than-normal drive on a warm day. (My normal drive is only 10 minutes, and spring is just starting to poke her head above ground here in Fargo.)
 

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I was going down a long hill in Idaho in "B" when the engine noise suddenly changed its TONE. Noticed that the Batteries were completely charged, ALL green. Shifted into "D" immediately & the noise returned to normal. While climbing the next "HILL" the batteries gauge dropped to 2 "PINK" bars. which went to blue after cresting & starting back downhill.
 

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As Im looking to buy a Prius, Ive recently read a lot of Toyota publications and burried deep in one was a statement that the batteries are not allowed to fall below 30% and not to exceed 70% charge under normal conditions to increase battery life.
 
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