Is This "Normal" ??

[jabecker]

My local dealer couldn't answer this question, so I'm turning to you experts!

I have a 2005 Prius. On the way home every day I go down a long hill. By the time I get to the bottom of the hill, the battery is usually fully charged -- i.e. all bars are green. If I get stopped by the light at the bottom, and the battery is fully charged the ICE cycles quickly on and off with about a 2- or 3-second pause between cycles... On (pause) off (pause) (on) pause (off) pause, etc. It cycles until the car moves forward again. Allowing the car to roll forward 1 or 2 feet, foot off gas pedal, usually stops the on-off thing.

Is this normal? What's causing it?

Other than this, I have absolutely no complaints! I love my Prius! It seems to run fine other than what I said above, and at just over 5000 miles I'm regularly averaging over 50 MPG commuting mainly on surface streets.

[usbseawolf2000]

It is normal. Your Prius is trying to protect your HV battery pack. Too full or too discharge can shorten the battery life. So, MG1 is "dumping" those extra electricity by spinning the gas engine without any fuel.

Dennis

[jabecker]

Cool! Thanks for the quick response.

I thought it might be something like that. My dealer's shop, when asked, stated that there was "no way that the battery could be charged more than 75%." Since I regularly see it charged more than that, I knew they were... misinformed.

[Bill Merchant]

[font=Comic Sans MS:6e3cf6d36f]But what you see on the screen, JABecker, is not the complete SOC range. With tolerence in mind, the screen battery shows the range from say 30% blinking pink to 80% solid green.

The car is smart enough to take care of itself, though it is startling to have the ICE switch on with a fully charged battery.[/font:6e3cf6d36f]

[efusco]

<div class='quotetop'>QUOTE(jabecker\";p=\"105216)</div>

Cool!  Thanks for the quick response.

I thought it might be something like that.  My dealer's shop, when asked, stated that there was \"no way that the battery could be charged more than 75%.\"  Since I regularly see it charged more than that, I knew they were...  misinformed.[/b]

Well, they're actually pretty much correct on that point.

The Energy screen's battery display shows only the 40%-80% range of the battery's total SOC. Thus, when it's fully green, the battery has the capacity to charge another 20%, but the programming of the ECU won't allow that...and that's why your ICE is spinning up at the bottom of that long hill. It senses that you're at or maybe even slightly above that 80% SOC level at it's protecting the battery from getting charged any higher.

[jabecker]

Thanks for all of the info, efusco, Bill Merchant and usbseawolf2000. I guess my dealer's shop and I need to define our terms better when we're talking! I will give them the benefit of the doubt.

[Hylander]

Thanks for the battery insight; one question.
My battery level is always between level 2 and level 6 (mostly at level 6), and it is always blue. It was in the green (level 7) for about 10 seconds once. I have about 300 miles on the Highlander. Somehow I would expect the battery to be "green" more then "never"... Is this normal or do I have a problem?

[Bill Merchant]

[font=Comic Sans MS:520233d32a]I think it's probably normal. I live at the bottom of a long hill with a 25 MPH speed limit. Coming home I (regeratively) brake down the hill and at the bottom, as I pull into my house, my battery indicator is sometimes solid green. Once it was even cycling the ICE on and off to dump charge. But my battery is normally in the blue range. I've only seen pink once, and never flashing.

Fully charged – solid green, Normal – blue, Low – pink, Very Low – flashing pink.[/font:520233d32a]