# [EVDL] Cabin Heat



## EVDL List (Jul 27, 2007)

It's that time of year and hoping for more cabin heat than the 200W ceramic
running on the 12V accessory battery that I have now.

Could the 96VDC pack run a 1500W panel heater designed for 120VAC
http://tinyurl.com/2668lq ?

Use a 12VDC radiator fan supplied from the auxiliary battery to move air
around it?

I am thinking with only 96VDC instead of 120VAC, the heater would produce
1200W, use 12.5A?

Will this work?
JLC


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## EVDL List (Jul 27, 2007)

If there are no electronic controls or fans, just a heating element,
it should work. It would run at 960 watts -- remember watts is
proportional to the square of voltage if resistance is a constant.

Z



> Jay Caplan <[email protected]> wrote:
> > It's that time of year and hoping for more cabin heat than the 200W ceramic
> > running on the 12V accessory battery that I have now.
> >
> ...


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## EVDL List (Jul 27, 2007)

Jay,

I use a different approach - an electric vest and a pair of ski gloves.
This keeps me nice and toasty, and uses a fraction of the power that the
ceramic heater does. I use the ceramic heater to defrost the windsheild
when needed.

Widder makes good electric vests:
http://www.widder.com/html/Product/System1/index.html

You can buy them in many motorcycle parts/accessory shops.

Ralph


Jay Caplan writes:
> 
> It's that time of year and hoping for more cabin heat than the 200W ceramic
> running on the 12V accessory battery that I have now.
> 
> Could the 96VDC pack run a 1500W panel heater designed for 120VAC
> http://tinyurl.com/2668lq ?
> 
> Use a 12VDC radiator fan supplied from the auxiliary battery to move air
> around it?
> 
> I am thinking with only 96VDC instead of 120VAC, the heater would produce
> 1200W, use 12.5A?
> 
> Will this work?
> JLC
> 
> 
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

> On 28 Nov 2007 at 8:06, Jay Caplan wrote:
> 
> > I am thinking with only 96VDC instead of 120VAC, the heater would produce
> > 1200W, use 12.5A?
> ...


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## EVDL List (Jul 27, 2007)

I am confused. Remembering back to electronics 101 

DC equivalent is .636 of peak right? 120VAC that is 60V peak x .636 =
38.16 VDC

So 96VDC converted to equivalent AC would be 96V / .636 = 150.94 volts
peak which would be 301.886 VAC 

What am I missing? 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of David Roden
Sent: Wednesday, November 28, 2007 12:30
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Cabin Heat



> On 28 Nov 2007 at 8:06, Jay Caplan wrote:
> 
> > I am thinking with only 96VDC instead of 120VAC, the heater would
> > produce 1200W, use 12.5A?
> ...


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## EVDL List (Jul 27, 2007)

On Nov 28, 2007 1:04 PM, Dewey, Jody R ATC COMNAVAIRLANT, N422G5G


> <[email protected]> wrote:
> > I am confused. Remembering back to electronics 101
> >
> > DC equivalent is .636 of peak right? 120VAC that is 60V peak x .636 =
> ...


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## EVDL List (Jul 27, 2007)

> Brian Staffanson wrote:
> > thinking of building my own heater for my car... along these lines:
> > http://silenceisdefeat.org/~lgtngstk/Sites/Circuits/12V_Heater/Heater.html
> 
> ...


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## EVDL List (Jul 27, 2007)

I think one of the great things about the ceramic heaters is that if the
fan dies they self limit. What happens if your fan dies?
The other think is that I can buy them new for $15.00 all day.

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## EVDL List (Jul 27, 2007)

Hello EVDL,

I've been following this thread a bit...

I'm working on setting up cabin heat for a Toyota
pickup, with ceramic heaters powered from my 320V
nominal pack. I have two elements, and each actually
has 5 different circuits, so different wiring
configurations allow the heater to draw different
currents and consequently produce different amounts of
heat.

I'm having some trouble with a relay, though. Any
ideas on what relays to use, so it is controlled by a
12V switch?

Thanks,
Andy



EV Album Overview page:
http://www.austinev.org/evalbum/1430
EV Build Blog (my website in progress):
http://toyotaev.blogspot.com/2007/11/introduction.html


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## EVDL List (Jul 27, 2007)

just a historical interjection, in case someone can benefit from knowing.
the EV VW Golf (called Rabbit in USA) that VW made around 1995 (200 cars 
total) actually used a fuel burning cabin heater. I've seen two here in 
denmark and the owner said the fuel tank was kept in the design and is 
used for that very purpose.
it's not a conversion. an official VW product.
huge siemens AC drive but it was only spec'ed to 70km/h iirc even though 
the VW museum says 100km/h. dreadful 0-50km/h time. it was called 
citystromer (city electric)

Dan

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## EVDL List (Jul 27, 2007)

If you use the stock blower, the current will increase
as you put more air over the element. Mine ranges
from about 19A at low to 43A at high, but I'm running
1/2 the voltage you are.




> --- Andrew Goodman <[email protected]> wrote:
> 
> > Hello EVDL,
> >
> ...


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## EVDL List (Jul 27, 2007)

Hello Andrew,

Use a contactor design for resistance circuits. They are normally design 
for voltages up to 600 volts at 10 to 600 ampere with any coil voltage you 
want. Relays are normally design for control voltages.

What you need is something like a Kilovac contactor that is rated for you 
battery pack volt and about 50 amp rating with a 12 volt coil. You can see 
how they look like at evparts.com. They have only the 200 amp one in stock, 
but they can order you the smaller 50 amp rating one.

If you have a source to a wholesale heating supply house that handles Tyco 
products which Kilovac is one of them, you might be able to order these 
contactors from there but EV Parts or EV Source may be better for you.

These are small single pole type, and its prefer to use two of these or a 
double pole type, so you can isolated both battery lines from the charging 
circuit. You could have over 413 charging volts on one heater line if you 
only use a single pole contactor.

My first EV came with one pole main contactor and a one pole heater 
contactor, and I had my DC-DC converter burn out, main motor communtator 
arcing over to the motor shaft to ground and some arcing the motor 
controller while the battery charger was on.

I prevented the battery charging current on these components by installing 
two contactors on the battery pack power leads that go to the main 
controller contactor and controller and all other taps off the battery pack, 
I use two contactors or a two pole contactor for these circuits.

Roland


----- Original Message ----- 
From: "Andrew Goodman" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Saturday, December 01, 2007 1:10 AM
Subject: Re: [EVDL] Cabin Heat


> Hello EVDL,
>
> I've been following this thread a bit...
>
> I'm working on setting up cabin heat for a Toyota
> pickup, with ceramic heaters powered from my 320V
> nominal pack. I have two elements, and each actually
> has 5 different circuits, so different wiring
> configurations allow the heater to draw different
> currents and consequently produce different amounts of
> heat.
>
> I'm having some trouble with a relay, though. Any
> ideas on what relays to use, so it is controlled by a
> 12V switch?
>
> Thanks,
> Andy
>
>
>
> EV Album Overview page:
> http://www.austinev.org/evalbum/1430
> EV Build Blog (my website in progress):
> http://toyotaev.blogspot.com/2007/11/introduction.html
>
>
> 
> ____________________________________________________________________________________
> Never miss a thing. Make Yahoo your home page.
> http://www.yahoo.com/r/hs
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
For subscription options, see
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## EVDL List (Jul 27, 2007)

http://www.mpja.com/prodinfo.asp?number=17288+RL
how many amps does it draw?
A bit expensive for four of them. 

Jack



> --- Andrew Goodman <[email protected]> wrote:
> 
> > Hello EVDL,
> >
> ...


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## EVDL List (Jul 27, 2007)

I would recommend against solid state relays for safety/isolation
relays. They're just like the transistors in a controller: if they
fail, they will probably fail as a short circuit.

-Morgan LaMoore



> Jack Murray <[email protected]> wrote:
> > http://www.mpja.com/prodinfo.asp?number=17288+RL
> > how many amps does it draw?
> > A bit expensive for four of them.
> ...


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## EVDL List (Jul 27, 2007)

>I would recommend against solid state relays for safety/isolation
>relays. They're just like the transistors in a controller: if they
>fail, they will probably fail as a short circuit.

I would generally concur.
However, it's very common to use SSR's for a lot of similar loads.
Stage lighting for one.
Kiln heater control for another.

After my wife's kiln controller failed, I bought a surplus replacement that
did not have internal solid state control, but recommended an external SSR
for the job.
I found one reasonably priced that was rated for the load (DC control, AC
load: 15A, 115v+, 60hz).
It's worked flawlessly for the past several years now, maintaining set point
temperature within 1deg and with cycle times as short as 2seconds.
With nominally 1500watts of heat, it's certainly in the range of what folks
want to control in an EV.

I would agree that for safety, you want more protection---e.g. a fuse or
circuit breaker.
But for thermal load control, manual or automatic, the SSR's of today are
far more reliable than they were 20years ago.
The key to longevity though is to ensure correct snubber and other
protection circuitry is put in place.

-Myles Twete, Portland, Or.

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## EVDL List (Jul 27, 2007)

> Myles Twete <[email protected]> wrote:
> >
> > I found one reasonably priced that was rated for the load (DC control, AC
> > load: 15A, 115v+, 60hz).
> ...


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## EVDL List (Jul 27, 2007)

Re: SSR's. I also had the same idea, but quickly learned (at least in my
case) that SSR's do not work on DC. I was able to switch them ON, but not
OFF. I queried this list and was informed that SSR's need a zero crossing
point, only available through AC, unless an elaborate circuit is built to
switch the SSR to OFF. DC relays seem like the way to go.
(If I'm misinformed, I'd sure like to know. I have a box of twenty 50a
SSR's, all dressed up and no place to go.)
Roger Daisley
Pullman, WA

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## EVDL List (Jul 27, 2007)

It entirely depends on the type of solid state relay. It sounds like
you got SCR based relays, which need a zero crossing to turn off.
However, if you get a SSR that uses MOSFETs, it will work just fine at
DC.

-Morgan LaMoore



> Roger Daisley <[email protected]> wrote:
> > Re: SSR's. I also had the same idea, but quickly learned (at least in my
> > case) that SSR's do not work on DC. I was able to switch them ON, but not
> > OFF. I queried this list and was informed that SSR's need a zero crossing
> ...


----------



## EVDL List (Jul 27, 2007)

> Morgan LaMoore wrote:
> > It entirely depends on the type of solid state relay. It sounds like
> > you got SCR based relays, which need a zero crossing to turn off.
> > However, if you get a SSR that uses MOSFETs, it will work just fine
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > Almost all SSRs use SCRs or Triacs. These parts are inexpensive,
> > reliable, and have a low on-state voltage drop of about 1v to 1.5v so
> > efficiency is good. However, they only switch AC.
> ...


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## EVDL List (Jul 27, 2007)

> John G. Lussmyer wrote:
> > Lee Hart wrote:
> >> Almost all SSRs use SCRs or Triacs. These parts are inexpensive,
> >> reliable, and have a low on-state voltage drop of about 1v to 1.5v so
> ...


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## EVDL List (Jul 27, 2007)

I ordered 3 to try. I will be trying one as a replacement for the big honkin open frame relay I am currently using to switch on my heater. I had several of these laying around that I bought off Ebay and didn't see anything that looked signficantly better that was rated for the job until these came along. I'm switching about 80 volts at 24 amps. I'll post results after I try one.

damon


> Date: Sun, 2 Dec 2007 13:48:49 -0600
> From: [email protected]
> To: [email protected]
> Subject: Re: [EVDL] Cabin Heat
>


> > John G. Lussmyer wrote:
> >> Lee Hart wrote:
> >>> Almost all SSRs use SCRs or Triacs. These parts are inexpensive,
> >>> reliable, and have a low on-state voltage drop of about 1v to 1.5v so
> ...


----------



## EVDL List (Jul 27, 2007)

Thanks for the comments from people on the list, just installed 2 systems on
the 96V LeCar, will see how they do this winter.

The first is a 120VAC 2 level space heater, plugged into the block under the
hood that feeds the chargers with line current. Sits on the front passenger
floor. I will turn this on while the car is plugged in and in the garage, 2
hours before driving. This heater offers choice of 1000 or 1500 watts with
fan, fused, variable thermostatically controlled, with upset safety switch.
These are common from any discount store. It heats the car up to whatever
temp you set, maybe 80 F. . The 10 batteries inside the cabin are also
heated up to this temp and store a lot of heat energy due to their weight
620 lb. Have to go to a 12 ga extension cord to accomodate both the chargers
and the 1500 watts of heater.

So, when you unplug you take off with a warm car. If someone were to plug in
while at work, they could have a timer set up to turn on this heater an hour
before leaving work and have a warm car to start the drive home. Same for
returning from an airport flight, or leave it plugged in while in a store if
power is available.

The second is a metal drum heater 9"x 60" 3300W at 240VAC meant to wrap
around a drum with clamps - just happened to have this in the shop and not
being used. This draws 528 watts at 96VDC from the batteries. 16 ga cable,
fused at 10A, SPST on/off switch. We straightened it out and mounted it in
the floor on edge just in front of the back seat. It does not get warm
enough to cause anything to burn, but too hot to hold your hand on it. This
is meant to be turned on as soon as the car begins to feel cool inside and
will draw 5.5 A, act as a large radiator. It may not have enough wattage,
but it is something to try. We may need to go with a larger and smaller
element with forced air, but wanted to see how this does first since it was
on hand. Since the trips I make are just a couple of hours, and the climate
mild in TN, this may be enough. Will report at the end of the winter.

There already was a defrost system for front and back glass that works off
the 12VDC auxiliary battery from the original Electricar modification.
JLC

----- Original Message ----- 
From: "Jay Caplan" <[email protected]>
To: <[email protected]>
Sent: Wednesday, November 28, 2007 8:06 AM
Subject: Cabin Heat


> It's that time of year and hoping for more cabin heat than the 200W
ceramic
> running on the 12V accessory battery that I have now.
>
> Could the 96VDC pack run a 1500W panel heater designed for 120VAC
> http://tinyurl.com/2668lq ?
>
> Use a 12VDC radiator fan supplied from the auxiliary battery to move air
> around it?
>
> I am thinking with only 96VDC instead of 120VAC, the heater would produce
> 1200W, use 12.5A?
>
> Will this work?
> JLC
>
>

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