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Discussion Starter #1
It appears that cold temperatures strongly affect the performance of EVs.
One report I read was
that the Mitsubishi iMiev was getting 80-100 miles per charge in moderate
temperature, but more like
50 in freezing weather.

It appears that this is a result not only of the battery temperature but
also the energy needed to
heat the passenger compartment. While the Nissan Leaf can start out with a
warm battery/cabin when it
is hooked up for charging, for longer drives and when parked w/o a charging
station, it will get
cold in cold weather.

I wonder if anyone has looked at the economics and fuel consumption of
providing a small
gasoline/propane heater to warm the battery and cabin? Would this consume a
lot of fuel? Also,
if the car is equipped with a heat pump, would the heat pump greatly reduce
the amount of fuel
needed to warm the car and battery?

Any thoughts on this would be appreciated.

Thanks,

-- Larry Gales


--
Larry Gales
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Discussion Starter #2
A heat pump is an a/c system in reverse, figure on many watts used for heat.
Along with dc-ac converters. Ceramic grid heaters work real well, amperage
drops off significantly as they get hotter. Eberspacher makes gas, diesel,
kerosene burners that either heat the air, or heat antifreeze for the
original heater cores. Isn't the idea of an EV to get away from burning
stuff? I really like the ceramic grids. They also fit where the original
heater cores were mounted.
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Discussion Starter #3
Let's take a look at this from a biological perspective: do you wish to
heat the compartment, or do you wish to heat the occupants?

If the desire is to heat the occupants, heated seats and steering wheels
give the best efficiency by targeting the heat (or coolant) directly to
the object by conductive heating/cooling. Similar to the efficiencies
of using heated concrete floors in houses instead of forced-air.

It would also allow for selectively heating based on passenger load.

Some experimentation would be required to see how the human body deals
with the body core mass moving the heat from the seat to the extremities
-- heated seats heat the body core, would this be enough to keep toes
warm???

I have not done/studied this, but it *should* be more efficient as the
heat transfer is better with conductive than radiant/convective and you
might be able to design in a thermal mass into the seat (if YOUR mass
isn't big enough).

Hmm... now that's an experiment easily done in the Twike!

[email protected]

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Larry Gales
Sent: Tuesday, November 16, 2010 3:03 PM
To: Electric Vehicle Discussion List; SEVA
Subject: [EVDL] Cold weather operation of an EV

It appears that cold temperatures strongly affect the performance of
EVs.
One report I read was
that the Mitsubishi iMiev was getting 80-100 miles per charge in
moderate
temperature, but more like
50 in freezing weather.

It appears that this is a result not only of the battery temperature but
also the energy needed to
heat the passenger compartment. While the Nissan Leaf can start out with
a
warm battery/cabin when it
is hooked up for charging, for longer drives and when parked w/o a
charging
station, it will get
cold in cold weather.

I wonder if anyone has looked at the economics and fuel consumption of
providing a small
gasoline/propane heater to warm the battery and cabin? Would this
consume a
lot of fuel? Also,
if the car is equipped with a heat pump, would the heat pump greatly
reduce
the amount of fuel
needed to warm the car and battery?

Any thoughts on this would be appreciated.

Thanks,

-- Larry Gales


--
Larry Gales
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Discussion Starter #4
On 16 Nov 2010 at 13:02, Larry Gales wrote:

> I wonder if anyone has looked at the economics and fuel consumption of
> providing a small gasoline/propane heater to warm the battery and cabin?
> Would this consume a lot of fuel?

Many EVs have been so fitted. The 1976 Citicar had a propane heater as an
option. Regrettably, it wasn't too helpful, since it was unvented. The
products of combustion included water vapor, which fogged the windows when
it was in operation. (The Citicar's idea of a defogger was a feeble little
12v heating strip attached to the base of the windshield. Later models
added a blower that sent a few baby-breath wisps of hot-motor and ozone
scented air to the windshield.)

IIRC, gasoline heaters were fitted to some of the Jet Industries conversions
in the late '70s and early '80s.

Solectria offered an optional "fuel fired" heater (it used diesel fuel, I
think) on Forces in the late '90s and early 2000s. They were reportedly
pretty effective.

Purists sometimes objected to fueled heaters, but FWIW fuel burned this way
tends to burn more cleanly and completely than fuel burned in an ICE.

> Also, if the car is equipped with a heat pump, would the heat pump
> greatly reduce the amount of fuel needed to warm the car and battery?

The GM EV-1 had a heat pump. I think it harvested the small amount of waste
heat from the drive system (and of course from the ambient air).

I don't recall ever seeing any performance trials on it, but home air-source
heat pumps can have a COP in the range of 2.5 to 3.5 when used in moderate
climates. Since GM never offered the EV1 for lease in cold areas, its heat
pump probably was quite a bit more efficient than the simple resistive
heaters that most of us use. Thus while it would certainly affect range, it
wouldn't be as big a hit as a resistive heater.

A big problem with winter operation of EVs is that most of them are
conversions. ICEs don't have to worry about the civilized niceties you
expect in your home, such as insulation or double pane window glass. The
ICE throws off enormous amounts of "free" waste heat, and you have to get
rid of it anyway to keep the ICE from failing, so why bother conserving any
of that heat? Just blast it into the cabin.

Very few conversions try to improve this situation. Indeed it doesn't
appear to me that any of the automakers' hybrids has bothered to reduce
winter heat loss from the cabin. Nor do I see any indication that GM or
Nissan has made an effort to make the Volt or Leaf easier and more
economical to heat.

A well designed EV would be more frugal with its heat.

David Roden
EVDL Administrator
http://www.evdl.org/


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Discussion Starter #5
Heated seats do work great, but heated air is needed for windshield
defrosting.
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Discussion Starter #6
Hi,

> Let's take a look at this from a biological perspective: do you wish to
> heat the compartment, or do you wish to heat the occupants?

I just had a thought: motorcyclists can use an electric vest or electric leggings or electric heated gloves (or heated grips). I'll bet these would be the most efficient way to keep warm in an EV. These devices are out there, and they run on 12v DC, so they could fit in pretty easily?

Sincerely, Neil
http://neilblanchard.blogspot.com/


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Discussion Starter #7
Hello,

> Heated seats do work great, but heated air is needed for windshield
> defrosting.

Not necessarily -- Ford used to have a windshield defroster that was a very thin coating of gold that was an electric defroster without the lines. It worked very quickly, as I remember, and I'll bet it would also help exclude solar heat for cooler summer driving?

Sincerely, Neil
http://neilblanchard.blogspot.com/


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Discussion Starter #8
The finished product will be dictated by the owners desires and practicality.
My experience has been that the owners want their ev's set up like the
original vehicle. Heated windshields are far more efficient then heating air
and blowing it across the windshield. Can it be retrofitted to an older car?
Heated suits work well, ask any 8th Air Force bomber crewman. Will the
operator want to "suit up" for cold weather rides? Heating up a car full of
air takes many watts, but it sure is easy and convenient.
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Discussion Starter #9
On Tue, Nov 16, 2010 at 4:42 PM, Childress, Matthew
<[email protected]>wrote:

> Some experimentation would be required to see how the human body deals
> with the body core mass moving the heat from the seat to the extremities
> -- heated seats heat the body core, would this be enough to keep toes
> warm???
>
>
>
Well, since I live in Michigan I have been able to unwillingly do much
experimentation. No, heating your core will not make your toes or fingers
warm. I can say this because shoveling snow in -5C weather is still cold.
You can bundle up your core as much as you want and it might be warm but
your toes and fingers will still feel like they might fall off. Heated
steering wheels will help the drivers hands but do nothing for the passenger
or anyone's toes. Also, one of the largest heat sinks in the human body is
the head. If it's not warm, you're not warm. So, you need to wear a decent
thermal hat.

Unfortunately human extremities are too far away from the core to be
effectively temperature controlled during large discrepancies between
ambient and body temperature. Wearing more clothing will help but you can
only bundle up so well if you still plan to drive.
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Discussion Starter #10
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Discussion Starter #11
Here in Montana, I only needed to run one cab heater at 640 watts all winter
long and did not have to run a second cab heater at 840 watts and a 1000
watt hot water heater that uses the existing heater core.

For some reason it only got down to 0 degrees for only couple of hours and
then never got below 20 degrees for long period of times. The average was
36 degrees. It normally gets down to 30 below for days at a time which I
never seen for the last 10 years.

Using only the 640 watt heater which comes on 15 to 20 minutes before I
leave, the inside cab temperature has been up to about 80 F. These heaters
are 120 vac 60 hz which can either run off commercial power when the main AC
plug is connected or can be transfer to a onboard 5kw 120 vac 60 hz inverter
that can run off a deep cycle 12 volt 135 AH battery and alternator design
for deep cycle charging. Also can run the inverter off a group of parallel
45 Amp DC-DC converters.

This one 640 watt heater kept all the glass defrosted without running the
additional defroster heater. One thing I did when I modified the El Camino,
was to increase the R-Factor of the cab space and rework the air ducts so it
would circulated the heated air much like is done in a house.

In many vehicles with a engine, the engine may heat up the engine coolant as
high as 240 degrees. This is temper with outside air with a damper to lower
the temperature to the cab. I adjusted this heater damper, so I can close
it all way shut and rework the duct work, so it circulates the heated air.

After this mod I did, I found that it now takes only 50 degree water
temperature from the 1000 watt heater unit to keep the windshield defrosted.
I would have to use 180 degree water if it was temper with -30 outside air
which is not needed for a EV system.

Now the inside cab heaters which are mounted under the dash back on the fire
wall with about 2 inches of space behind them which has a grill for return
air. This first blow out the heated air directly on the passengers, heat up
the seats and than flows back to the front windshield back down to the
defrosted outlets which I turn into inlets by using a electrical operated
duct doors.

Another thing that helps is installing 2 inch thick foam rubber on the floor
which was shape to make a completely flat floor which had a lot of recesses
in it. The lay a foam back carpet over that. I also install 3/4 inch thick
foam rubber behind the door panels and on the front and rear fire walls
which was also cover with a foam back carpet.

This now leaves the windows where I calculated the heat lost and heater
requirements as we do when we calculated the size of heater units for
buildings.

It is known that a single pane of 1/8 thick glass that is one square foot is
1-R factor. We change the R factor into a U factor by dividing the R into
one or U = 1/R = 1/1 = 1 U factor.

My vehicle class area is 25 square feet and if I want to calculated the
glass lost at -30 below ambient air at a 70 F inside temperate which is a
100 degree temperature difference, then we use the formula:


Btur's = Square Foot x U factor x Temperature Difference

= 25 sf x 1 U x 100 degree TD

= 2500 Btur's

It is known that a 1000 watt heater is rated at 3412 btus, so the glass it
self will take about (1000 wt x 2500 btu)/3412 btu = 737 watt heater.

You then will have to calculated all the U-factors of all the other panels
in the vehicle.

Normally when it's a clear day without no overcast, the ambient temperature
will be the lowest. But you can take advantage of solar gains by parking the
vehicle to allow the sun to heat the vehicle. I always park my EV with the
large glass hatch cover that is over the insulated battery box pointing
directly at the sun. I had read temperatures up to 80 F in that compartment
at -35 below.

Roland









----- Original Message -----
From: "Collin Kidder" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Wednesday, November 17, 2010 3:52 AM
Subject: Re: [EVDL] Cold weather operation of an EV


> On Tue, Nov 16, 2010 at 4:42 PM, Childress, Matthew
> <[email protected]>wrote:
>
> > Some experimentation would be required to see how the human body deals
> > with the body core mass moving the heat from the seat to the extremities
> > -- heated seats heat the body core, would this be enough to keep toes
> > warm???
> >
> >
> >
> Well, since I live in Michigan I have been able to unwillingly do much
> experimentation. No, heating your core will not make your toes or fingers
> warm. I can say this because shoveling snow in -5C weather is still cold.
> You can bundle up your core as much as you want and it might be warm but
> your toes and fingers will still feel like they might fall off. Heated
> steering wheels will help the drivers hands but do nothing for the
> passenger
> or anyone's toes. Also, one of the largest heat sinks in the human body is
> the head. If it's not warm, you're not warm. So, you need to wear a decent
> thermal hat.
>
> Unfortunately human extremities are too far away from the core to be
> effectively temperature controlled during large discrepancies between
> ambient and body temperature. Wearing more clothing will help but you can
> only bundle up so well if you still plan to drive.
> -------------- next part --------------
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Discussion Starter #12
Several things:

1- You can definitely wear warmer clothes. Like vapor barrier boots. You
don't need 12v-electric heated clothes to stay warm.
2- If you got no-heat system you can keep the window open a little bit to
prevent the windshield to frost over.
3- Have the window scrapper handy to scrap from the inside.
4- Supposedly, a snorkel will work as well.

else

5- They make propane heaters that run outside the cab, and connect with the
glycol and the original heater core. We used the 5500 btu version and it
kept the truck warm till -20C.

Mike Golub
Fairbanks, Alaska

Roland Wiench <[email protected]> wrote:

> Here in Montana, I only needed to run one cab heater at 640 watts all
> winter
> long and did not have to run a second cab heater at 840 watts and a 1000
> watt hot water heater that uses the existing heater core.
>
> For some reason it only got down to 0 degrees for only couple of hours and
> then never got below 20 degrees for long period of times. The average was
> 36 degrees. It normally gets down to 30 below for days at a time which I
> never seen for the last 10 years.
>
> Using only the 640 watt heater which comes on 15 to 20 minutes before I
> leave, the inside cab temperature has been up to about 80 F. These heaters
> are 120 vac 60 hz which can either run off commercial power when the main
> AC
> plug is connected or can be transfer to a onboard 5kw 120 vac 60 hz
> inverter
> that can run off a deep cycle 12 volt 135 AH battery and alternator design
> for deep cycle charging. Also can run the inverter off a group of parallel
> 45 Amp DC-DC converters.
>
> This one 640 watt heater kept all the glass defrosted without running the
> additional defroster heater. One thing I did when I modified the El
> Camino,
> was to increase the R-Factor of the cab space and rework the air ducts so
> it
> would circulated the heated air much like is done in a house.
>
> In many vehicles with a engine, the engine may heat up the engine coolant
> as
> high as 240 degrees. This is temper with outside air with a damper to
> lower
> the temperature to the cab. I adjusted this heater damper, so I can close
> it all way shut and rework the duct work, so it circulates the heated air.
>
> After this mod I did, I found that it now takes only 50 degree water
> temperature from the 1000 watt heater unit to keep the windshield
> defrosted.
> I would have to use 180 degree water if it was temper with -30 outside air
> which is not needed for a EV system.
>
> Now the inside cab heaters which are mounted under the dash back on the
> fire
> wall with about 2 inches of space behind them which has a grill for return
> air. This first blow out the heated air directly on the passengers, heat
> up
> the seats and than flows back to the front windshield back down to the
> defrosted outlets which I turn into inlets by using a electrical operated
> duct doors.
>
> Another thing that helps is installing 2 inch thick foam rubber on the
> floor
> which was shape to make a completely flat floor which had a lot of recesses
> in it. The lay a foam back carpet over that. I also install 3/4 inch
> thick
> foam rubber behind the door panels and on the front and rear fire walls
> which was also cover with a foam back carpet.
>
> This now leaves the windows where I calculated the heat lost and heater
> requirements as we do when we calculated the size of heater units for
> buildings.
>
> It is known that a single pane of 1/8 thick glass that is one square foot
> is
> 1-R factor. We change the R factor into a U factor by dividing the R into
> one or U = 1/R = 1/1 = 1 U factor.
>
> My vehicle class area is 25 square feet and if I want to calculated the
> glass lost at -30 below ambient air at a 70 F inside temperate which is a
> 100 degree temperature difference, then we use the formula:
>
>
> Btur's = Square Foot x U factor x Temperature Difference
>
> = 25 sf x 1 U x 100 degree TD
>
> = 2500 Btur's
>
> It is known that a 1000 watt heater is rated at 3412 btus, so the glass it
> self will take about (1000 wt x 2500 btu)/3412 btu = 737 watt heater.
>
> You then will have to calculated all the U-factors of all the other panels
> in the vehicle.
>
> Normally when it's a clear day without no overcast, the ambient temperature
> will be the lowest. But you can take advantage of solar gains by parking
> the
> vehicle to allow the sun to heat the vehicle. I always park my EV with the
> large glass hatch cover that is over the insulated battery box pointing
> directly at the sun. I had read temperatures up to 80 F in that
> compartment
> at -35 below.
>
> Roland
>
>
>
>
>
>
>
>
>
> ----- Original Message -----
> From: "Collin Kidder" <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Wednesday, November 17, 2010 3:52 AM
> Subject: Re: [EVDL] Cold weather operation of an EV
>
>
> > On Tue, Nov 16, 2010 at 4:42 PM, Childress, Matthew
> > <[email protected]>wrote:
> >
> > > Some experimentation would be required to see how the human body deals
> > > with the body core mass moving the heat from the seat to the
> extremities
> > > -- heated seats heat the body core, would this be enough to keep toes
> > > warm???
> > >
> > >
> > >
> > Well, since I live in Michigan I have been able to unwillingly do much
> > experimentation. No, heating your core will not make your toes or fingers
> > warm. I can say this because shoveling snow in -5C weather is still cold.
> > You can bundle up your core as much as you want and it might be warm but
> > your toes and fingers will still feel like they might fall off. Heated
> > steering wheels will help the drivers hands but do nothing for the
> > passenger
> > or anyone's toes. Also, one of the largest heat sinks in the human body
> is
> > the head. If it's not warm, you're not warm. So, you need to wear a
> decent
> > thermal hat.
> >
> > Unfortunately human extremities are too far away from the core to be
> > effectively temperature controlled during large discrepancies between
> > ambient and body temperature. Wearing more clothing will help but you can
> > only bundle up so well if you still plan to drive.
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL:
> >
> http://lists.sjsu.edu/mailman/private/ev/attachments/20101117/9c6b624b/attachment.html
> > _______________________________________________
> > | REPLYING: address your message to [email protected] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
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Registered
Joined
·
70 Posts
Discussion Starter #13
Well, according to this site:

http://www.air-n-water.com/heater_fuel.htm

you can determine the fuel consumption of a propane heater in gallons by
dividing 91,500 by the BTU's needed. Now if a 5500 BTU heater (mentioned
below) will keep you warm down to -20C (-4F), then one gallon of propane
will create that heat for 16.6 hours. At an average of 30 MPH that works
out to 500 MPG!. Given that you probably won't use the heater more than
half the time and often a less than full power, you would get well over 1000
MPG. So I suspect a gas/propane heater might make good sense for an EV.

-- Larry

m gol <[email protected]> wrote:

> Several things:
>
> 1- You can definitely wear warmer clothes. Like vapor barrier boots. You
> don't need 12v-electric heated clothes to stay warm.
> 2- If you got no-heat system you can keep the window open a little bit to
> prevent the windshield to frost over.
> 3- Have the window scrapper handy to scrap from the inside.
> 4- Supposedly, a snorkel will work as well.
>
> else
>
> 5- They make propane heaters that run outside the cab, and connect with the
> glycol and the original heater core. We used the 5500 btu version and it
> kept the truck warm till -20C.
>
> Mike Golub
> Fairbanks, Alaska
>
> On Wed, Nov 17, 2010 at 6:10 AM, Roland Wiench <[email protected]> wrote:
>
> > Here in Montana, I only needed to run one cab heater at 640 watts all
> > winter
> > long and did not have to run a second cab heater at 840 watts and a 1000
> > watt hot water heater that uses the existing heater core.
> >
> > For some reason it only got down to 0 degrees for only couple of hours
> and
> > then never got below 20 degrees for long period of times. The average
> was
> > 36 degrees. It normally gets down to 30 below for days at a time which I
> > never seen for the last 10 years.
> >
> > Using only the 640 watt heater which comes on 15 to 20 minutes before I
> > leave, the inside cab temperature has been up to about 80 F. These
> heaters
> > are 120 vac 60 hz which can either run off commercial power when the main
> > AC
> > plug is connected or can be transfer to a onboard 5kw 120 vac 60 hz
> > inverter
> > that can run off a deep cycle 12 volt 135 AH battery and alternator
> design
> > for deep cycle charging. Also can run the inverter off a group of
> parallel
> > 45 Amp DC-DC converters.
> >
> > This one 640 watt heater kept all the glass defrosted without running the
> > additional defroster heater. One thing I did when I modified the El
> > Camino,
> > was to increase the R-Factor of the cab space and rework the air ducts so
> > it
> > would circulated the heated air much like is done in a house.
> >
> > In many vehicles with a engine, the engine may heat up the engine coolant
> > as
> > high as 240 degrees. This is temper with outside air with a damper to
> > lower
> > the temperature to the cab. I adjusted this heater damper, so I can
> close
> > it all way shut and rework the duct work, so it circulates the heated
> air.
> >
> > After this mod I did, I found that it now takes only 50 degree water
> > temperature from the 1000 watt heater unit to keep the windshield
> > defrosted.
> > I would have to use 180 degree water if it was temper with -30 outside
> air
> > which is not needed for a EV system.
> >
> > Now the inside cab heaters which are mounted under the dash back on the
> > fire
> > wall with about 2 inches of space behind them which has a grill for
> return
> > air. This first blow out the heated air directly on the passengers, heat
> > up
> > the seats and than flows back to the front windshield back down to the
> > defrosted outlets which I turn into inlets by using a electrical operated
> > duct doors.
> >
> > Another thing that helps is installing 2 inch thick foam rubber on the
> > floor
> > which was shape to make a completely flat floor which had a lot of
> recesses
> > in it. The lay a foam back carpet over that. I also install 3/4 inch
> > thick
> > foam rubber behind the door panels and on the front and rear fire walls
> > which was also cover with a foam back carpet.
> >
> > This now leaves the windows where I calculated the heat lost and heater
> > requirements as we do when we calculated the size of heater units for
> > buildings.
> >
> > It is known that a single pane of 1/8 thick glass that is one square foot
> > is
> > 1-R factor. We change the R factor into a U factor by dividing the R
> into
> > one or U = 1/R = 1/1 = 1 U factor.
> >
> > My vehicle class area is 25 square feet and if I want to calculated the
> > glass lost at -30 below ambient air at a 70 F inside temperate which is a
> > 100 degree temperature difference, then we use the formula:
> >
> >
> > Btur's = Square Foot x U factor x Temperature Difference
> >
> > = 25 sf x 1 U x 100 degree TD
> >
> > = 2500 Btur's
> >
> > It is known that a 1000 watt heater is rated at 3412 btus, so the glass
> it
> > self will take about (1000 wt x 2500 btu)/3412 btu = 737 watt heater.
> >
> > You then will have to calculated all the U-factors of all the other
> panels
> > in the vehicle.
> >
> > Normally when it's a clear day without no overcast, the ambient
> temperature
> > will be the lowest. But you can take advantage of solar gains by parking
> > the
> > vehicle to allow the sun to heat the vehicle. I always park my EV with
> the
> > large glass hatch cover that is over the insulated battery box pointing
> > directly at the sun. I had read temperatures up to 80 F in that
> > compartment
> > at -35 below.
> >
> > Roland
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Collin Kidder" <[email protected]>
> > To: "Electric Vehicle Discussion List" <[email protected]>
> > Sent: Wednesday, November 17, 2010 3:52 AM
> > Subject: Re: [EVDL] Cold weather operation of an EV
> >
> >
> > > On Tue, Nov 16, 2010 at 4:42 PM, Childress, Matthew
> > > <[email protected]>wrote:
> > >
> > > > Some experimentation would be required to see how the human body
> deals
> > > > with the body core mass moving the heat from the seat to the
> > extremities
> > > > -- heated seats heat the body core, would this be enough to keep toes
> > > > warm???
> > > >
> > > >
> > > >
> > > Well, since I live in Michigan I have been able to unwillingly do much
> > > experimentation. No, heating your core will not make your toes or
> fingers
> > > warm. I can say this because shoveling snow in -5C weather is still
> cold.
> > > You can bundle up your core as much as you want and it might be warm
> but
> > > your toes and fingers will still feel like they might fall off. Heated
> > > steering wheels will help the drivers hands but do nothing for the
> > > passenger
> > > or anyone's toes. Also, one of the largest heat sinks in the human body
> > is
> > > the head. If it's not warm, you're not warm. So, you need to wear a
> > decent
> > > thermal hat.
> > >
> > > Unfortunately human extremities are too far away from the core to be
> > > effectively temperature controlled during large discrepancies between
> > > ambient and body temperature. Wearing more clothing will help but you
> can
> > > only bundle up so well if you still plan to drive.
> > > -------------- next part --------------
> > > An HTML attachment was scrubbed...
> > > URL:
> > >
> >
> http://lists.sjsu.edu/mailman/private/ev/attachments/20101117/9c6b624b/attachment.html
> > > _______________________________________________
> > > | REPLYING: address your message to [email protected] only.
> > > | Multiple-address or CCed messages may be rejected.
> > > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > > | OTHER HELP: http://evdl.org/help/
> > > | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
> > >
> >
> > _______________________________________________
> > | REPLYING: address your message to [email protected] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
> >
> -------------- next part --------------
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> _______________________________________________
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
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>



--
Larry Gales
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·
Registered
Joined
·
70 Posts
Discussion Starter #14
"This is temper with outside air with a damper to lower the temperature to
the cab." It can be, but usually has a fully closed position controlled with
an inside/outside air selector. I checked mine to ensure the input to the
blower from outside is fully closed when set at "inside". My car has no
insulation to speak of, except in the battery boxes. I checked the firewall
to ensure no air leaks (had the dash out), but if I pre-heat the car before
leaving, it is cold inside within 15 -20 minutes, depending on outside
temperature.
--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Cold-weather-operation-of-an-EV-tp3045685p3047942.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

_______________________________________________
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·
Registered
Joined
·
70 Posts
Discussion Starter #15
Keeping the window open a little does nothing, neither does a scraper.
Windows still fog.

Point of reference: I have an old CJ-8 jeep with a soft top (plenty of fresh
air) that is currently missing the defroster hose/duct from the heater box.
I drove it a couple times last week in cold/snowy/rainy weather and it was
just dangerous due to visibility from windows fogging. I had a towel handy
to wipe the windsheild from the inside, and could not keep it clear enough,
especially at night. It was rather scary to drive.

Brett

m gol <[email protected]> wrote:

> Several things:
>
> 1- You can definitely wear warmer clothes. Like vapor barrier boots. You
> don't need 12v-electric heated clothes to stay warm.
> 2- If you got no-heat system you can keep the window open a little bit to
> prevent the windshield to frost over.
> 3- Have the window scrapper handy to scrap from the inside.
> 4- Supposedly, a snorkel will work as well.
>
> else
>
> 5- They make propane heaters that run outside the cab, and connect with the
> glycol and the original heater core. We used the 5500 btu version and it
> kept the truck warm till -20C.
>
> Mike Golub
> Fairbanks, Alaska
>
> On Wed, Nov 17, 2010 at 6:10 AM, Roland Wiench <[email protected]> wrote:
>
> > Here in Montana, I only needed to run one cab heater at 640 watts all
> > winter
> > long and did not have to run a second cab heater at 840 watts and a 1000
> > watt hot water heater that uses the existing heater core.
> >
> > For some reason it only got down to 0 degrees for only couple of hours
> and
> > then never got below 20 degrees for long period of times. The average
> was
> > 36 degrees. It normally gets down to 30 below for days at a time which I
> > never seen for the last 10 years.
> >
> > Using only the 640 watt heater which comes on 15 to 20 minutes before I
> > leave, the inside cab temperature has been up to about 80 F. These
> heaters
> > are 120 vac 60 hz which can either run off commercial power when the main
> > AC
> > plug is connected or can be transfer to a onboard 5kw 120 vac 60 hz
> > inverter
> > that can run off a deep cycle 12 volt 135 AH battery and alternator
> design
> > for deep cycle charging. Also can run the inverter off a group of
> parallel
> > 45 Amp DC-DC converters.
> >
> > This one 640 watt heater kept all the glass defrosted without running the
> > additional defroster heater. One thing I did when I modified the El
> > Camino,
> > was to increase the R-Factor of the cab space and rework the air ducts so
> > it
> > would circulated the heated air much like is done in a house.
> >
> > In many vehicles with a engine, the engine may heat up the engine coolant
> > as
> > high as 240 degrees. This is temper with outside air with a damper to
> > lower
> > the temperature to the cab. I adjusted this heater damper, so I can
> close
> > it all way shut and rework the duct work, so it circulates the heated
> air.
> >
> > After this mod I did, I found that it now takes only 50 degree water
> > temperature from the 1000 watt heater unit to keep the windshield
> > defrosted.
> > I would have to use 180 degree water if it was temper with -30 outside
> air
> > which is not needed for a EV system.
> >
> > Now the inside cab heaters which are mounted under the dash back on the
> > fire
> > wall with about 2 inches of space behind them which has a grill for
> return
> > air. This first blow out the heated air directly on the passengers, heat
> > up
> > the seats and than flows back to the front windshield back down to the
> > defrosted outlets which I turn into inlets by using a electrical operated
> > duct doors.
> >
> > Another thing that helps is installing 2 inch thick foam rubber on the
> > floor
> > which was shape to make a completely flat floor which had a lot of
> recesses
> > in it. The lay a foam back carpet over that. I also install 3/4 inch
> > thick
> > foam rubber behind the door panels and on the front and rear fire walls
> > which was also cover with a foam back carpet.
> >
> > This now leaves the windows where I calculated the heat lost and heater
> > requirements as we do when we calculated the size of heater units for
> > buildings.
> >
> > It is known that a single pane of 1/8 thick glass that is one square foot
> > is
> > 1-R factor. We change the R factor into a U factor by dividing the R
> into
> > one or U = 1/R = 1/1 = 1 U factor.
> >
> > My vehicle class area is 25 square feet and if I want to calculated the
> > glass lost at -30 below ambient air at a 70 F inside temperate which is a
> > 100 degree temperature difference, then we use the formula:
> >
> >
> > Btur's = Square Foot x U factor x Temperature Difference
> >
> > = 25 sf x 1 U x 100 degree TD
> >
> > = 2500 Btur's
> >
> > It is known that a 1000 watt heater is rated at 3412 btus, so the glass
> it
> > self will take about (1000 wt x 2500 btu)/3412 btu = 737 watt heater.
> >
> > You then will have to calculated all the U-factors of all the other
> panels
> > in the vehicle.
> >
> > Normally when it's a clear day without no overcast, the ambient
> temperature
> > will be the lowest. But you can take advantage of solar gains by parking
> > the
> > vehicle to allow the sun to heat the vehicle. I always park my EV with
> the
> > large glass hatch cover that is over the insulated battery box pointing
> > directly at the sun. I had read temperatures up to 80 F in that
> > compartment
> > at -35 below.
> >
> > Roland
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Collin Kidder" <[email protected]>
> > To: "Electric Vehicle Discussion List" <[email protected]>
> > Sent: Wednesday, November 17, 2010 3:52 AM
> > Subject: Re: [EVDL] Cold weather operation of an EV
> >
> >
> > > On Tue, Nov 16, 2010 at 4:42 PM, Childress, Matthew
> > > <[email protected]>wrote:
> > >
> > > > Some experimentation would be required to see how the human body
> deals
> > > > with the body core mass moving the heat from the seat to the
> > extremities
> > > > -- heated seats heat the body core, would this be enough to keep toes
> > > > warm???
> > > >
> > > >
> > > >
> > > Well, since I live in Michigan I have been able to unwillingly do much
> > > experimentation. No, heating your core will not make your toes or
> fingers
> > > warm. I can say this because shoveling snow in -5C weather is still
> cold.
> > > You can bundle up your core as much as you want and it might be warm
> but
> > > your toes and fingers will still feel like they might fall off. Heated
> > > steering wheels will help the drivers hands but do nothing for the
> > > passenger
> > > or anyone's toes. Also, one of the largest heat sinks in the human body
> > is
> > > the head. If it's not warm, you're not warm. So, you need to wear a
> > decent
> > > thermal hat.
> > >
> > > Unfortunately human extremities are too far away from the core to be
> > > effectively temperature controlled during large discrepancies between
> > > ambient and body temperature. Wearing more clothing will help but you
> can
> > > only bundle up so well if you still plan to drive.
> > > -------------- next part --------------
> > > An HTML attachment was scrubbed...
> > > URL:
> > >
> >
> http://lists.sjsu.edu/mailman/private/ev/attachments/20101117/9c6b624b/attachment.html
> > > _______________________________________________
> > > | REPLYING: address your message to [email protected] only.
> > > | Multiple-address or CCed messages may be rejected.
> > > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > > | OTHER HELP: http://evdl.org/help/
> > > | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
> > >
> >
> > _______________________________________________
> > | REPLYING: address your message to [email protected] only.
> > | Multiple-address or CCed messages may be rejected.
> > | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> > | OTHER HELP: http://evdl.org/help/
> > | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
> >
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