Rapid cycle between charge/dischrge

JoelO · 10-23-2008, 12:14 PM

I just took delivery of my Prius last week and do not know if what I'm seeing is normal. Has anyone else seen this and is it normal?

While at highway speed (60-75 mph) on level terrain - both with and without cruise control - I see the battery cycle between charge and discharge at a rate faster than 2 cycles per second. The display shows charging for a period of a few seconds and then enters a cycle of rapid charge/discharge for several seconds before settling back to several seconds in a charge state. When accelerating or going up/down hill this does not happen for the obvious reasons. I swear that I can feel the power fluctuations as well but that might be my imagination.

I understand why the system would cycle, I'm just concerned that such a rapid frequency is a symptom of a problem.

ddan · 10-23-2008, 12:22 PM

I hope not.... I have noticed the same thing, though I can't remember feeling surges. I am a new Prius driver as well (<2 weeks). Avg 51 mpg so far.

**efusco** · 10-23-2008, 12:33 PM

Totally normal and exactly what the car should do. The Engine will run at a nearly constant RPM, that means sometimes it produces a little more energy than is being demanded and will show charge to the battery, when it needs a little more it take some from the battery...all part of maintaining maximum MPG.

Those of us with instrumentation to watch know that those fluxes are very small, usually less than 6-12 amps either direction.

john1701a · 10-23-2008, 12:48 PM

The video download from this webpage provides a sample of what we normally see... much like you described.

.

**TonyPSchaefer** · 10-23-2008, 01:03 PM

Since no one else said it,

welcome to PriusChat and congrats on your new Prius!

ddan · 10-23-2008, 01:06 PM

Thank you. Have been reading and learning tons. Great people and info!

richard schumacher · 10-23-2008, 05:49 PM

Now, if you were seeing the number of bars on the state-of-charge display change by two bars per second, that would be bad.

10-23-2008, 12:14 PM	#1
JoelO Junior Member Join Date: Oct 2008 Location: Minneapolis Posts: 1 My Car: 2009 Prius Model: Package: #5 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Rapid cycle between charge/dischrge I just took delivery of my Prius last week and do not know if what I'm seeing is normal. Has anyone else seen this and is it normal? While at highway speed (60-75 mph) on level terrain - both with and without cruise control - I see the battery cycle between charge and discharge at a rate faster than 2 cycles per second. The display shows charging for a period of a few seconds and then enters a cycle of rapid charge/discharge for several seconds before settling back to several seconds in a charge state. When accelerating or going up/down hill this does not happen for the obvious reasons. I swear that I can feel the power fluctuations as well but that might be my imagination. I understand why the system would cycle, I'm just concerned that such a rapid frequency is a symptom of a problem.

10-23-2008, 12:22 PM	#2
ddan Junior Member Join Date: Oct 2008 Location: Bryn Mawr Posts: 14 My Car: 2009 Prius Model: Package: #5 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Rapid cycle between charge/dischrge I hope not.... I have noticed the same thing, though I can't remember feeling surges. I am a new Prius driver as well (<2 weeks). Avg 51 mpg so far.

10-23-2008, 12:33 PM	#3
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 17,231 My Car: 2004 Prius Model: Package: #9 Thanks: 49 Thanked 249 Times in 148 Posts Friends: 37	Re: Rapid cycle between charge/dischrge Totally normal and exactly what the car should do. The Engine will run at a nearly constant RPM, that means sometimes it produces a little more energy than is being demanded and will show charge to the battery, when it needs a little more it take some from the battery...all part of maintaining maximum MPG. Those of us with instrumentation to watch know that those fluxes are very small, usually less than 6-12 amps either direction.

10-23-2008, 12:48 PM	#4
john1701a Senior Member Join Date: Jan 2004 Location: Minnesota Posts: 3,375 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 9 Thanked 145 Times in 70 Posts Friends: 12	Re: Rapid cycle between charge/dischrge The video download from this webpage provides a sample of what we normally see... much like you described. .

10-23-2008, 01:03 PM	#5
TonyPSchaefer Your Friendly Moderator Join Date: May 2004 Location: Far-North Chicagoland Posts: 10,500 My Car: 2004 Prius Model: Package: #9 Thanks: 39 Thanked 165 Times in 106 Posts Friends: 23	Re: Rapid cycle between charge/dischrge Since no one else said it, welcome to PriusChat and congrats on your new Prius!

10-23-2008, 01:06 PM	#6
ddan Junior Member Join Date: Oct 2008 Location: Bryn Mawr Posts: 14 My Car: 2009 Prius Model: Package: #5 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Rapid cycle between charge/dischrge Thank you. Have been reading and learning tons. Great people and info!

10-23-2008, 05:49 PM	#7
richard schumacher Destination: Eschaton Join Date: Mar 2004 Location: United States Posts: 5,510 My Car: 2004 Prius Model: N/A Package: #6 Thanks: 99 Thanked 93 Times in 66 Posts Friends: 0	Re: Rapid cycle between charge/dischrge Now, if you were seeing the number of bars on the state-of-charge display change by two bars per second, that would be bad.

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