Re: [EVDL] EVLN: Improving an EV's Cabin Heating System

[Cor van de Water via EV]

As we discussed here a couple years ago, this same principle was already
patented by an EV controller/conversion company (Wavedriver) over 2
decades ago as well.
So there is a lot of re-invention going on...

On another note: the patent is quite worthless. It was worthless when it
was patented by Wavedriver and it still is worthless today, due to the
"conflict of interest" between the controller and motor cooling loop
(staying as cold as possible) and the cabin heating liquid temp (being
as hot as possible to provide plenty heating of a freezing cabin).
So, either you have a badly cooled controller/motor, OR you have no
cabin heat. I experienced this first-hand in my first-ever V2G converted
S10 by Wavedriver for PG, commissioned in 1995, where they installed
this "invention".
I found the original thread documented on DIY Electric Car:
http://www.diyelectriccar.com/forums/showthread.php/re-evdl-ev-aircon-24
754.html

Cor van de Water 
Chief Scientist 
Proxim Wireless 
  
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-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV
Sent: Wednesday, December 02, 2015 6:49 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] EVLN: Improving an EV's Cabin Heating System

brucedp5 via EV wrote:
> http://www.hybridcars.com/wp-content/uploads/2015/11/Slide11.jpg
> (schematic)  Tesla patent shows waste heat from the drive motor and
> electronics being used to heat the cabin

I did this way back in the 1970's. There should be a description of my 
system on the EVDL archives. The 1970's CitiCar also used waste heat 
from the motor for the windshield defroster.

The result? As a practical matter, there is so little waste heat from an

EV's motor and controller that it's hardly worth the bother. If the car 
takes 10kw to cruise down the road, and its motor is 90% efficient, you 
only have 1kw of waste heat. And, that's low-quality heat... the 
temperature is only a little above the outside ambient.

I found it was better to use the mass of the batteries as a "heat 
flywheel". During charging, warm the batteries with heaters and the 
waste heat from charging. During driving, transfer this heat to the 
cabin. That cools the batteries; but they are so massive that they don't

lose enough temperature to matter in (say) a 1-hour commute to work.

My EV had 14 golf cart batteries (1000 lbs) in a 2" styrafoam box. Air 
ducts let me circulate air through the battery box, then a cabin heater,

into the cabin, and then back into the battery box. The motor could also

be ducted in, but the smell produced by the brushes was annoying, and it

didn't add enough heat to bother with.

The article also confuses the peak load needed to warm up a cold car 
(6kw) with the much lower average load needed to hold it at temperature 
(1-2kw). Since an EV would normally be plugged in when parked to 
recharge, it makes more sense to pre-heat the car with AC power, while 
it is still plugged in. Then you only need 1-2kw to hold it at 
temperature while driving.

Another thing: We've learned to insulate our homes, and plug leaks to 
keep down the outrageous heating and cooling costs. But cars still have 
virtually no insulation, and leak air like a sieve. It takes more power 
to heat/cool a normal car than for a small house! This was tolerable 
with ICEs, where you had vast amounts of "free" waste heat and huge 
excesses of horsepower to run air conditioners. But so far, the auto 
company's EVs are built the same way... no insulation, lots of air
leaks.

-- 
Humanity is acquiring all the right technology for all the wrong
reasons. -- R. Buckminster Fuller
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] EVLN: Improving an EV's Cabin Heating System

[Roland via EV]

   
At about this time, the electric heaters came on in my EV, while I am setting 
here typing this.  I have three AC heaters, one 500 watt hot water heater for 
the existing heater core, a 640 watt driver side cab heater and a 840 watt 
passenger side cab heater.  

 

Today, because the temperature is only 30 degrees, the 640 watt comes on.  I 
have a on dash transfer switch that can select between commercial power or on 
board power using a 5 kw DC to AC inverter.  If I want heating while the EV is 
in the drive mode, than the power comes from a rotating inverter-alternator 
that puts out both 13.5 to 16 volts DC and 110 VDC 7Kw which is inverted to 120 
VAC 60 cycles 5kw.

 

This unit also acts like a REGEN braking to slow down the EV on steep icy 
hills. 

 

Roland 


- Original Message - 

From: Lee Hart via EV 

To: Electric Vehicle Discussion List 

Sent: Wednesday, December 02, 2015 7:49 AM

Subject: Re: [EVDL] EVLN: Improving an EVâ?Ts Cabin Heating System



brucedp5 via EV wrote:
> http://www.hybridcars.com/wp-content/uploads/2015/11/Slide11.jpg
> (schematic)  Tesla patent shows waste heat from the drive motor and
> electronics being used to heat the cabin

I did this way back in the 1970's. There should be a description of my 
system on the EVDL archives. The 1970's CitiCar also used waste heat 
from the motor for the windshield defroster.

The result? As a practical matter, there is so little waste heat from an 
EV's motor and controller that it's hardly worth the bother. If the car 
takes 10kw to cruise down the road, and its motor is 90% efficient, you 
only have 1kw of waste heat. And, that's low-quality heat... the 
temperature is only a little above the outside ambient.

I found it was better to use the mass of the batteries as a "heat 
flywheel". During charging, warm the batteries with heaters and the 
waste heat from charging. During driving, transfer this heat to the 
cabin. That cools the batteries; but they are so massive that they don't 
lose enough temperature to matter in (say) a 1-hour commute to work.

My EV had 14 golf cart batteries (1000 lbs) in a 2" styrafoam box. Air 
ducts let me circulate air through the battery box, then a cabin heater, 
into the cabin, and then back into the battery box. The motor could also 
be ducted in, but the smell produced by the brushes was annoying, and it 
didn't add enough heat to bother with.

The article also confuses the peak load needed to warm up a cold car 
(6kw) with the much lower average load needed to hold it at temperature 
(1-2kw). Since an EV would normally be plugged in when parked to 
recharge, it makes more sense to pre-heat the car with AC power, while 
it is still plugged in. Then you only need 1-2kw to hold it at 
temperature while driving.

Another thing: We've learned to insulate our homes, and plug leaks to 
keep down the outrageous heating and cooling costs. But cars still have 
virtually no insulation, and leak air like a sieve. It takes more power 
to heat/cool a normal car than for a small house! This was tolerable 
with ICEs, where you had vast amounts of "free" waste heat and huge 
excesses of horsepower to run air conditioners. But so far, the auto 
company's EVs are built the same way... no insulation, lots of air leaks.

-- 
Humanity is acquiring all the right technology for all the wrong
reasons. -- R. Buckminster Fuller
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, 
www.sunrise-ev.com
___
UNSUBSCRIBE: 
http://www.evdl.org/help/index.html#usub
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Read EVAngel's EV News at http://evdl.org/evln/
Please discuss EV drag racing at NEDRA 
(http://groups.yahoo.com/group/NEDRA)

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