What's optimal "warm-up" time before turning on the fan?

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by mikenancy1, Nov 16, 2012.

  1. mikenancy1

    mikenancy1 2012 PiP (Base), '10 Highlander Hybrid, '05 Prius

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    When trying to get the most out of EV mode first thing in the morning, what's your experience on how long the car needs to run before turning on the heater? It's disheartening to see that solid MPG line suddenly plummet when I put the heat on!
     
  2. Germwise

    Germwise Junior Member

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    I don't understand this question. in Auto, the prius doesn't push air through the vents until it can deliver hot air. So I guess the question is when do you get cold?
     
  3. Frank Perkins

    Frank Perkins Member

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    I think I understand. YOu want to know how long the ICE has been running before you blast the heat?
     
  4. priuskitty

    priuskitty PIP FAN

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    your MPG is still going to "plummet" whenever you need heat. And the only way to get heat in a PIP is when ICE is running. EV doesn't supply any heat in a PIP except for the seat heaters.
     
  5. silentak1

    silentak1 Since 2005

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    I think i know what you're asking. In most cars (including the Prius, someone correct me if i'm wrong), heat is "drawn" from the engine, simplistically speaking. So if you turn on the car and immediately hit the heater, bam... mpg plummets as the engine continously runs (even when you are stopped) to warm-up the engine. To answer your question, there's no simple answer. I think it depends on how many minutes the ICE has been running... I'd say at least 10 minutes of cumulative ICE. So that could be 30 minutes (20 on EV + 10 on ICE) or it could really be 10 minutes (e.g. if your commute is uphill for the entire first 10 minutes, no way in hell you're running EV uphill...unless you do 1mph LOL).
     
  6. cwerdna

    cwerdna Senior Member

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    I don't think there's any way to definitively determine the # of minutes. I think one is best off using something (e.g. Scangauge II, Torque app for Android, etc.) to monitor coolant temperature (FWT on ScanGauge).
     
  7. silentak1

    silentak1 Since 2005

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    Yeah, that is probably true. For those without any monitoring tools, we have to give them a guess though you're right, really the right # of minutes will vary so much on weather and driving styles.
     
  8. cwerdna

    cwerdna Senior Member

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    It absolutely will vary and can vary a lot. Climbing uphill at slow speeds in warm weather will heat up the engine pretty quick. Driving at highway speeds in cold weather doesn't seem to.

    I've seen FWT on my Gen 2 generally higher in stop/go, city traffic than highway.
     
  9. jdcollins5

    jdcollins5 Senior Member

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    I monitor the ICE coolant temp with the SGII or either wait until I know I am hitting a spot where the ICE will be running continuously before I raise the cabin temp. It is disheartening to be sitting at a stop and watching the mpg fall as the ICE continues to run to warm the cabin.

    I ususally lower the temp setpoint to 66 while waiting for the ICE coolant to warm up. Once it is either warm or I hit a spot where I know the ICE will continue to run then raise it to 70 or 72.
     
  10. JimN

    JimN Let the games begin!

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    I don't turn the heat on until coolant temp is 150F & don't notice a significant hit. The PiP has the same ICE so...
     
  11. cwerdna

    cwerdna Senior Member

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  12. priuskitty

    priuskitty PIP FAN

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    see post #11
     
  13. bisco

    bisco cookie crumbler

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    the ice doesn't warm up in ev mode if you don't turn the heat on.
     
  14. priuskitty

    priuskitty PIP FAN

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    correct
     
  15. bisco

    bisco cookie crumbler

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    so if you're trying to get the most out of ev mode, how long do you have to wait before turning on the heat?
     
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