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Re: Getting enough heat in 2009 when I don't drive very far

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  • honolulusnowwhite
    The two PTC heaters are standard equipment in US cars. However, don t expect miracles to be performed by the electric heater as it consumes
    Message 1 of 17 , Jan 4, 2010
      The two PTC heaters are standard equipment in US cars. However, don't expect miracles to be performed by the electric heater as it consumes < 400W of power which is ~25% of a 1,500W hair dryer.

      Since the Prius gasoline engine is very efficient it doesn't produce much excess heat. Therefore you are bound to be disappointed with the cabin heating in very cold weather, especially if you take only short trips.

      Patrick Wong

      --- In toyota-prius@yahoogroups.com, "Mike Dimmick" <mike@...> wrote:
      >
      > > -----Original Message-----
      > > On Behalf Of Karl H
      > > Subject: [toyota-prius] Re: Getting enough heat in 2009 when I don't drive very far
      > >
      > > I have gotten in my car with a frozen windshield and I don't seem to get that heat.
      > >
      > > Either my PTC is defective or it just sucks.
      > >
      > The PTC heaters were an optional component for 'cold weather' regions. I don't think the USA got them, but Canada did.
    • Karl H
      ... OK, I am in one of the few places in the world where I have to drive south to get to a Northern country. (I am north of parts of Canada) I should have
      Message 2 of 17 , Jan 4, 2010
        --- In toyota-prius@yahoogroups.com, "Mike Dimmick" <mike@...> wrote:
        >
        > > -----Original Message-----
        > > From: toyota-prius@yahoogroups.com [mailto:toyota-prius@yahoogroups.com]
        > > On Behalf Of Karl H
        > > Sent: 31 December 2009 12:54
        > > To: toyota-prius@yahoogroups.com
        > > Subject: [toyota-prius] Re: Getting enough heat in 2009 when I don't drive
        > > very far
        > >
        > > I have gotten in my car with a frozen windshield and I don't seem to get
        > > that heat.
        > >
        > > Either my PTC is defective or it just sucks.
        > >
        > > My 2007 Prius is a package 2. Was it in all Prii?
        >
        > The PTC heaters were an optional component for 'cold weather' regions. I
        > don't think the USA got them, but Canada did. I know the UK didn't - we also
        > didn't get heated mirrors on Gen 2, while left-hand-drive cars in Europe
        > did, I think because they had one specification for all of continental
        > Europe.
        >
        > I think the relays are only fitted on cars where the heater is fitted. The
        > PTC relays are in the engine room relay box, which is behind the engine
        > itself, just below the wipers. Counting from left to right, the PTC relays
        > are number three and four, marked PTC HTR 1 and PTC HTR 2.
        >
        > In the main fuse box, where the jump start terminal is (driver's side of the
        > engine bay) there are two fuses marked PTC HTR 1 and PTC HTR 2. You should
        > check that the two fuses (rated 30A) are fitted, if the PTC heater is
        > present, and that they are unbroken. They're towards the top of the box in
        > the left-hand column as you stand in front of the car.
        >
        > These two fuses and relays supply current to the two electric heater
        > elements in the heater core. There's also a heater element somewhere in the
        > footwell air duct in the centre of the car - it's not clear whether this is
        > the front or rear footwells. This is controlled by the 50A PS HTR fuse and
        > PS HTR relay (furthest left in the engine room relay box). The three heating
        > elements should operate independently since they have different power
        > supplies.
        >
        > These are the conditions under which the electric heaters operate:
        >
        > - Car in READY, blower motor ON, i.e. not in AUTO, where - except when
        > defrosting - the blower doesn't start until sufficient engine coolant
        > temperature is reached.
        >
        > Heater core PTCs:
        >
        > - Air directed to foot, foot/defrost (windscreen), or defrost (windscreen)
        > - Engine coolant temperature below specified temperature
        > - Ambient temperature below specified temperature (if in defrost mode)
        > - 'Air mix damper' opening angle is above specified value
        >
        > Footwell heater:
        >
        > - In foot or foot/defrost mode
        > - Engine coolant temperature below specified temperature
        > - 'Air mix damper' opening angle above specified value
        >
        > The 'air mix damper' part is confusing. I think it's a pair of blades which
        > govern whether air is sent to, or bypasses, the heater core. The control
        > part describes three positions, all, half, or none going to the heater core;
        > this may be continuously variable, however. The service manual says that the
        > PTC heaters only operate with this set to MAX HOT, but I don't think it
        > means that you have to set the temperature to MAX HOT, just that all the air
        > would be going to the heater core.
        >
        > The electric heaters are turned off if the car's electrical load is high, so
        > they may not work if the headlights are on.
        >
        > With the coolant thermos fitted (standard in USA and Canada), I imagine that
        > the car will effectively dump the stored coolant into the heater core, then
        > only once that's cooled down below the desired temperature will it turn on
        > the PTC heater elements.
        >
        > --
        > Mike Dimmick
        >

        OK, I am in one of the few places in the world where I have to drive south to get to a Northern country. (I am north of parts of Canada) I should have those in my car!

        Those heaters would be nice.
      • David Kelly
        ... Am pretty sure it is on my 2007 package 6 from TN as I ve smelled electric heat a time or two. Never knew just how I prompted it. ... I haven t heard any
        Message 3 of 17 , Jan 4, 2010
          On Mon, Jan 04, 2010 at 01:44:47PM -0000, honolulusnowwhite wrote:
          > The two PTC heaters are standard equipment in US cars. However, don't
          > expect miracles to be performed by the electric heater as it consumes
          > < 400W of power which is ~25% of a 1,500W hair dryer.

          Am pretty sure it is on my 2007 package 6 from TN as I've smelled
          electric heat a time or two. Never knew just how I prompted it.

          > Since the Prius gasoline engine is very efficient it doesn't produce
          > much excess heat. Therefore you are bound to be disappointed with the
          > cabin heating in very cold weather, especially if you take only short
          > trips.

          I haven't heard any specifics as to just how short these trips are which
          are the focus of the discussion. 1 mile? 5 miles?

          My 2007 was garaged (attached but not heated) last night. 16F outside
          this morning according to the thermometer outside the kitchen window.
          Driving away the Prius immediately reported 30F but 4 miles later at
          speeds less than 40 MPH and light traffic (schools are not yet open) I
          was reaching to turn down the heat from 68 to 66. This is typical in my
          experience and its my guess similar to Phyllis's conditions.

          Yes, the Prius ICE is at the top of the game in thermodynamic efficiency
          but the engineer in me doubts 40% vs 30% efficiency is going to matter
          in the operation of the heater. OTOH *economy* (which is related but not
          the same thing as efficiency) could contribute. If one is only burning
          enough fuel for 50 MPG then there is only 0.02 gallons per mile to make
          heat and make the car go. Putting things in perspective most numbers
          have to double (or halve) before significantly altering the perceived
          performance. Then again all a car heater has to do to make me happy is
          blow warm air. I don't expect or want a hair dryer.

          Am not convinced there is anything inherently wrong or different about
          "Prius" contributing to this problem. Have little doubt there is
          something amiss with a single Prius in particular.

          --
          David Kelly N4HHE, dkelly@...
          ========================================================================
          Whom computers would destroy, they must first drive mad.
        • Karl H
          400W per heater, or total? OK, about 1/2 of a hairdryer is my car is not going to make a real difference, but if in the defrosters I SHOULD see some results
          Message 4 of 17 , Jan 5, 2010
            400W per heater, or total? OK, about 1/2 of a hairdryer is my car is not going to make a real difference, but if in the defrosters I SHOULD see some results instantly.

            On that note: Keep your fans on low while the ICE is cold, moving air quickly cools it. (Another thing I don't like about the auto-settings on the climate control)

            --- In toyota-prius@yahoogroups.com, "honolulusnowwhite" <patwong3@...> wrote:
            >
            > The two PTC heaters are standard equipment in US cars. However, don't expect miracles to be performed by the electric heater as it consumes < 400W of power which is ~25% of a 1,500W hair dryer.
            >
            > Since the Prius gasoline engine is very efficient it doesn't produce much excess heat. Therefore you are bound to be disappointed with the cabin heating in very cold weather, especially if you take only short trips.
            >
            > Patrick Wong
            >
            > --- In toyota-prius@yahoogroups.com, "Mike Dimmick" <mike@> wrote:
            > >
            > > > -----Original Message-----
            > > > On Behalf Of Karl H
            > > > Subject: [toyota-prius] Re: Getting enough heat in 2009 when I don't drive very far
            > > >
            > > > I have gotten in my car with a frozen windshield and I don't seem to get that heat.
            > > >
            > > > Either my PTC is defective or it just sucks.
            > > >
            > > The PTC heaters were an optional component for 'cold weather' regions. I don't think the USA got them, but Canada did.
            >
          • David Kelly
            ... 1200W is a typical hair dryer in the USA. 1500W is not uncommon. ... Auto does exactly what you claim it does not. It will not turn up the fan speed until
            Message 5 of 17 , Jan 10, 2010
              On Jan 5, 2010, at 7:30 AM, Karl H wrote:

              > 400W per heater, or total? OK, about 1/2 of a hairdryer is my car is not going to make a real difference, but if in the defrosters I SHOULD see some results instantly.

              1200W is a typical hair dryer in the USA. 1500W is not uncommon.

              > On that note: Keep your fans on low while the ICE is cold, moving air quickly cools it. (Another thing I don't like about the auto-settings on the climate control)


              Auto does exactly what you claim it does not. It will not turn up the fan speed until the ICE has reached a temperature that will result in heating. Auto mode on the HVAC will also cause the ICE to run to make heat in situations it otherwise would not run.

              In normal use I don't like Auto mode but it is the best mode for warm up.

              --
              David Kelly N4HHE, dkelly@...
              ========================================================================
              Whom computers would destroy, they must first drive mad.
            • Chris Yoder
              You can get aftermarket electric seat warmers and install them. Instant heat that puts a smile on your face! Here s a web site with step-by-step pictures of a
              Message 6 of 17 , Jan 24, 2010
                You can get aftermarket electric seat warmers and install them. Instant
                heat that puts a smile on your face!

                Here's a web site with step-by-step pictures of a friend who pulled this
                off:

                http://evnut.com/prius_seat_heat.htm

                -- Chris


                On 1/10/10 7:45 AM, "David Kelly" <dkelly@...> wrote:

                >
                > On Jan 5, 2010, at 7:30 AM, Karl H wrote:
                >
                >> 400W per heater, or total? OK, about 1/2 of a hairdryer is my car is not
                >> going to make a real difference, but if in the defrosters I SHOULD see some
                >> results instantly.
                >
                > 1200W is a typical hair dryer in the USA. 1500W is not uncommon.
                >
                >> On that note: Keep your fans on low while the ICE is cold, moving air quickly
                >> cools it. (Another thing I don't like about the auto-settings on the climate
                >> control)
                >
                >
                > Auto does exactly what you claim it does not. It will not turn up the fan
                > speed until the ICE has reached a temperature that will result in heating.
                > Auto mode on the HVAC will also cause the ICE to run to make heat in
                > situations it otherwise would not run.
                >
                > In normal use I don't like Auto mode but it is the best mode for warm up.
                >
                > --
                > David Kelly N4HHE, dkelly@...
                > ========================================================================
                > Whom computers would destroy, they must first drive mad.
                >
                >
                >
                >
                >
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