ICE cycling on & off at long stop lights

If the battery indicator is really showing full (8 green bars), then apparently this is fairly normal behaviour (although I've never experienced it personally). It's mucking around in an effort to use up some of the battery charge, because the battery has reached a higher level than it's happy with.

I'd only be concerned if there was no explanation for the battery being so full. Hopefully this is after a long downhill run?

 

This is a completely normal, though somewhat perplexing aspect of Prius behavior when the battery is full to the tippy-top. The computer is not confused, it is just trying to throw away some energy so as to keep the battery in its happy-range. If you hate it, shift into neutral when stopped at the traffic light. Ain't no thang.

 

<div class='quotetop'>QUOTE(tochatihu @ Jun 27 2006, 04:16 PM) [snapback]277557[/snapback]</div>

Of course then the battery will not be kept in its optimal state of charge, which will somewhat (but probably unnoticeably) reduce its life. And one day the driver might be stopped at a railroad crossing with the A/C running and completely drain the battery, which would be bad. A better strategy would be to leave it in D and get used to the behaviour. My goodness, I do go on, don't I.

 

<div class='quotetop'>QUOTE(richard schumacher @ Jun 27 2006, 07:40 PM) [snapback]277817[/snapback]</div>

Yes, but the ICE would not allow you to completely drain the battery...it would keep running, especially if the battery refused to accept a charge. You would just have the ICE to power you, but that would still get you moving.

 

<div class='quotetop'>QUOTE(mssmith95 @ Jun 27 2006, 10:56 PM) [snapback]277873[/snapback]</div>

?? The engine does not charge the battery when the drive is in "N". If there were a load on the battery (the A/C is running, or whatever), what would prevent the battery from eventually draining completely?

 

Richard you are absolutely right that there is no HV battery charging in "N". However the notion that the car would allow for example the A/C to discharge the battery to an unsafe condition has not been tested AFAIK. It also seems inconsistent with other aspects of the (very conservative) battery management system.

In other words, it might be true, but I doubt it personally. My Prius is of the earlier generation and thus not suited to test this. Some brave soul with a new model Prius might be willing to give it a try.

But not while stopped on a train crossing, please!

 

Another way to prevent the cycling is increase your electrical usage before & during slowdown. The A/C (inc. defrost) and rear window defrost suck a bunch of juice. Using "B" mode might help by engine brakeing, but really this is just the same thing the car is doing at stop (using the engine to disperse excess energy)

But the operation of your car sounds normal and nothing needs to be done, unless it bothers you in any way.

 

<div class='quotetop'>QUOTE(incisor @ Jun 27 2006, 09:49 AM) [snapback]277417[/snapback]</div>

What mode is the climate control in? I've had similar experiences like that with my car. Bumping the A/C temp up/down a few degrees will either keep the engine on, or make it stop completely. I think what is happening is that the demand on the climate control system is at some threshold where it thinks it needs the engine to help, then realizes it doesn't, and then goes back and forth. In theory, with a fully charged battery, it shouldn't be running the engine at all, unless you are trying to heat the cabin for some reason. And depending upon the set point of the climate control system, it may just be thinking that that is what you need/want.

 

<div class='quotetop'>QUOTE(richard schumacher @ Jun 28 2006, 09:45 AM) [snapback]278091[/snapback]</div>

Will have to test that...but why would anyone do that anyways? If one knows that the car does not charge in Neutral, why would one keeping the accessories running knowing that they are potentially going to kill the battery?

I guess it takes all kinds...

 

<div class='quotetop'>QUOTE(mssmith95 @ Jun 28 2006, 07:07 PM) [snapback]278312[/snapback]</div>

Probably because they *don't* know it: they didn't read the owner's manual well enough and they assumed that it's OK to do it based on their experience with non-hybrid cars.

 

<div class='quotetop'>QUOTE(incisor @ Jun 29 2006, 08:05 AM) [snapback]278581[/snapback]</div>

Do you mean you have the climate control system in Auto mode? Or that you have the system in manual mode. Or that you have selected a vent mode but turned the fan off and you are letting the movement of the car through the air force air through the vent system? Manual mode means that you select the vent mode (blowing at you face, feet, or windshield), the fan speed, and whether the A/C is on. In Auto mode, the system automatically sets the vent mode, fan speed, and whether to use the A/C compressor, based on the temperature set point you have selected and what the current cabin temperature is.

 

<div class='quotetop'>QUOTE(incisor @ Jun 27 2006, 12:49 PM) [snapback]277417[/snapback]</div>

I've seen this happend when am stuck in a traffic jammed and the battery
down to one bar.

--Hilore