Let the ICE run or shut it down?

HI MPG · 10-23-2009, 11:45 PM

This is my first hybrid, so I'm trying to be as efficient as possible. On several occasions I've ended my commute home with two bars left on the battery display. As I pull into my garage and hit the P, the ICE kicks in to start recharging the battery before I can hit the Power button to turn off the car. Is this the proper thing to do (shut down immediately), or should I let the ICE complete its cycle and recharge the battery slightly before I shut it down? I know that letting the ICE run to recharge isn't very efficient, but when I shut it down immediately, the ICE stops very abruptly (like a violent jerk against the mounts).
Is it healthy for both the engine and battery to continue in this manner? Would it be detrimental to the future reliability of the HSD components? Or should I just make sure that to end my commute with more than 2 bars?
Sorry if this has been discussed before. I did a search and couldn't a discussion topic relating to this issue.

Jim05 · 10-24-2009, 05:33 AM

Quote:

Originally Posted by HI MPG

This is my first hybrid, so I'm trying to be as efficient as possible. On several occasions I've ended my commute home with two bars left on the battery display. As I pull into my garage and hit the P, the ICE kicks in to start recharging the battery before I can hit the Power button to turn off the car. Is this the proper thing to do (shut down immediately), or should I let the ICE complete its cycle and recharge the battery slightly before I shut it down? I know that letting the ICE run to recharge isn't very efficient, but when I shut it down immediately, the ICE stops very abruptly (like a violent jerk against the mounts).
Is it healthy for both the engine and battery to continue in this manner? Would it be detrimental to the future reliability of the HSD components? Or should I just make sure that to end my commute with more than 2 bars?
Sorry if this has been discussed before. I did a search and couldn't a discussion topic relating to this issue.

IMHO, I would let it run despite the efficiency loss. To me, the loss of gas is better than possibly harming the engine by shutting off running under load (vice idle). Just an opinion, though...

**efusco** · 10-24-2009, 05:43 AM

There's no need to let it run at all. In fact, if the trigger for this seems to be hitting the Park button, but don't bother hitting the park button. Just pull in, stop, and power down...the car automatically goes into park.

The car will go through the battery charge balance procedure the next time you drive the car and it will do so much more efficently than it would by sitting in your garage.

patsparks · 10-24-2009, 10:58 AM

You are driving the last bit on EV aren't you?
If you are then maybe drop EV for the last little bit. I doubt it is doing any harm but it is my uneducated understanding that rechargeable batteries like to be stored with a good charge in them. Switch from EV mode for the last 200 yards. Also know that driving in EV mode doesn't save any gas, after all that energy you use in EV mode comes from gas.

(Oh my god, I am saying gas not petrol!!!)

Felt · 10-24-2009, 11:26 AM

HI MPG
IMHO I suspect you are "overthinking" the situation. Just drive normally, and this amazing vehicle will do all the thinking. I rarely touch the EV button ... only maybe if I am moving from one parking spot in a lot to a safer spot (I hate door dings). I have never had to use the PWR button. My G3, IV is averaging 54 mpg w/ 5000 miles on the odeometer. BTW, I just changed the oil, and my mileage average is higher .... I do not have an explanation .... maybe the tires were underinflated before the oil change?

Good luck.

dogfriend · 10-24-2009, 11:36 AM

The car is uber smart. Just drive and let it do what it needs to do.

dogfriend · 10-24-2009, 11:43 AM

Quote:

Originally Posted by patsparks

Oh my god, I am saying gas not petrol!!!

It was that trip to Detroit. You were infected with a virus. Now that virus will spread and the whole continent of Australia will be calling it gas. Have you used the phrase "Ya'll" (meaning all of you) yet?

spiderman · 10-24-2009, 12:43 PM

Quote:

Originally Posted by HI MPG

the ICE kicks in to start recharging the battery before I can hit the Power button to turn off the car. Is this the proper thing to do (shut down immediately), or should I let the ICE complete its cycle and recharge the battery slightly before I shut it down?

Great question and one I was wondering myself lately. Normally I make it to the 3rd floor parking with two or three bars. Lately I have been required to park on the 6th. The engine kicks in just as I park. I have been shutting it down while running thinking that like previously mentioned it would be more efficient charging while moving. It would be my guess that you would want to charge the battery if you know it would be sitting for a long time or if in really cold weather.

One thing I noticed is the brakes become really sensitive while coming down the garage floors. More so than say if the battery was full.

Matt Herring · 10-24-2009, 05:35 PM

Ditto with efusco...no need to waste gas letting the ICE run at the end of your drive. In fact, pulling into your destination parking space with 3 or less bars (ideally 3) is actually pretty good driving for efficiency...meaning you maxed out the last part of your trip in EV mode without allowing the ICE to kick in (unless you ran less than 3 bars for a great distance and forced ICE to kick in prior to parking).

It is better to run on low battery at the end of your trip than at the beginning or middle as you are not wasting ICE mid-trip to charge the battery. When I say "low battery" I don't mean the car is going to run out of battery energy...it means "lower than optimal energy" in terms of the hybrid system. If you run low battery during your drive you will notice higher than normal rpm's because some of the power normally used to propel the vehicle is diverted to charge the battery to optimal charge. You can test this by noticing how far you have to press the GO pedal to get the same acceleration while at 6 bars vs. 3 bars.

As you get more acquanited with your vehicle you can make mental notes as to how far from your destination you can begin EV mode. When you roughly know where that point is you can begin to extend that marker by coasting in drive where possible to grab small amounts of battery charge along the way. Before you know it, you are using EV mode 1/4, 1/2, 1 mile further from your destination and you will see your mpg go up and up...good luck!

patsparks · 10-24-2009, 08:04 PM

Quote:

Originally Posted by dogfriend

It was that trip to Detroit. You were infected with a virus. Now that virus will spread and the whole continent of Australia will be calling it gas. Have you used the phrase "Ya'll" (meaning all of you) yet?

No , not "y'all" but "all y'all"!

I'll know the infection is at full strength when I start spelling zoo. "zee oh oh" insead of "zed oh oh". I hate when my son does that.

Infection hey? Maybe that explains the sore throat and 2 weeks off work sick.

10-23-2009, 11:45 PM	#1
HI MPG Member Join Date: Aug 2009 Location: Orange County, CA Posts: 80 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 20 Thanked 17 Times in 12 Posts Friends: 0	Let the ICE run or shut it down? This is my first hybrid, so I'm trying to be as efficient as possible. On several occasions I've ended my commute home with two bars left on the battery display. As I pull into my garage and hit the P, the ICE kicks in to start recharging the battery before I can hit the Power button to turn off the car. Is this the proper thing to do (shut down immediately), or should I let the ICE complete its cycle and recharge the battery slightly before I shut it down? I know that letting the ICE run to recharge isn't very efficient, but when I shut it down immediately, the ICE stops very abruptly (like a violent jerk against the mounts). Is it healthy for both the engine and battery to continue in this manner? Would it be detrimental to the future reliability of the HSD components? Or should I just make sure that to end my commute with more than 2 bars? Sorry if this has been discussed before. I did a search and couldn't a discussion topic relating to this issue.

10-24-2009, 05:43 AM	#3
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 17,248 My Car: 2004 Prius Model: Package: #9 Thanks: 50 Thanked 260 Times in 156 Posts Friends: 37	Re: Let the ICE run or shut it down? There's no need to let it run at all. In fact, if the trigger for this seems to be hitting the Park button, but don't bother hitting the park button. Just pull in, stop, and power down...the car automatically goes into park. The car will go through the battery charge balance procedure the next time you drive the car and it will do so much more efficently than it would by sitting in your garage.

10-24-2009, 10:58 AM	#4
patsparks An Aussie perspective Join Date: Jul 2007 Location: Adelaide South Australia Posts: 9,244 My Car: 2004 Prius Model: N/A Package: Base Thanks: 128 Thanked 185 Times in 143 Posts Friends: 33	Re: Let the ICE run or shut it down? You are driving the last bit on EV aren't you? If you are then maybe drop EV for the last little bit. I doubt it is doing any harm but it is my uneducated understanding that rechargeable batteries like to be stored with a good charge in them. Switch from EV mode for the last 200 yards. Also know that driving in EV mode doesn't save any gas, after all that energy you use in EV mode comes from gas. (Oh my god, I am saying gas not petrol!!!)

10-24-2009, 11:26 AM	#5
Felt Senior Member Join Date: Jul 2009 Location: Northern Utah Posts: 111 My Car: 2010 Prius Model: IV Package: Navigation Thanks: 5 Thanked 12 Times in 11 Posts Friends: 0	Re: Let the ICE run or shut it down? HI MPG IMHO I suspect you are "overthinking" the situation. Just drive normally, and this amazing vehicle will do all the thinking. I rarely touch the EV button ... only maybe if I am moving from one parking spot in a lot to a safer spot (I hate door dings). I have never had to use the PWR button. My G3, IV is averaging 54 mpg w/ 5000 miles on the odeometer. BTW, I just changed the oil, and my mileage average is higher .... I do not have an explanation .... maybe the tires were underinflated before the oil change? Good luck.

10-24-2009, 11:36 AM	#6
dogfriend Human - Animal Hybrid Join Date: Feb 2007 Location: Carmichael, CA Posts: 4,967 My Car: 2007 Prius Model: Package: #6 Thanks: 288 Thanked 175 Times in 147 Posts Friends: 11	Re: Let the ICE run or shut it down? The car is uber smart. Just drive and let it do what it needs to do.

10-24-2009, 05:35 PM	#9
Matt Herring Senior Member Join Date: Apr 2009 Location: North Andover, MA Posts: 362 My Car: 2009 Prius Model: N/A Package: No Package Thanks: 3 Thanked 42 Times in 35 Posts Friends: 9	Re: Let the ICE run or shut it down? Ditto with efusco...no need to waste gas letting the ICE run at the end of your drive. In fact, pulling into your destination parking space with 3 or less bars (ideally 3) is actually pretty good driving for efficiency...meaning you maxed out the last part of your trip in EV mode without allowing the ICE to kick in (unless you ran less than 3 bars for a great distance and forced ICE to kick in prior to parking). It is better to run on low battery at the end of your trip than at the beginning or middle as you are not wasting ICE mid-trip to charge the battery. When I say "low battery" I don't mean the car is going to run out of battery energy...it means "lower than optimal energy" in terms of the hybrid system. If you run low battery during your drive you will notice higher than normal rpm's because some of the power normally used to propel the vehicle is diverted to charge the battery to optimal charge. You can test this by noticing how far you have to press the GO pedal to get the same acceleration while at 6 bars vs. 3 bars. As you get more acquanited with your vehicle you can make mental notes as to how far from your destination you can begin EV mode. When you roughly know where that point is you can begin to extend that marker by coasting in drive where possible to grab small amounts of battery charge along the way. Before you know it, you are using EV mode 1/4, 1/2, 1 mile further from your destination and you will see your mpg go up and up...good luck! __________________ 76.0 mpg 2nd place Hybrid/Diesel Division at 2009 AMEC Economy Competition in Fonda, NY (104 mile run on 8/23/09) Best Tank (400+ miles): 66.0 mpg over 402.6 miles from 8/10-21/2009 My Facebook: http://www.facebook.com/photo.php?pi...?id=1268001941 My Twitter: http://twitter.com/bone1124 www.ecomodder.com

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Headlights shut off	dslsurferboy	Gen II Prius Technical Discussion	8	09-19-2008 12:20 PM
Proper way to shut down	splashback	Gen II Prius Main Forum	11	05-15-2007 12:36 AM
Shut down!!	treehuger	Gen II Prius Technical Discussion	11	03-06-2007 04:18 PM
Shut the A/C off?	Walker1	Gen II Prius Main Forum	20	03-07-2006 11:08 AM