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Re: [EVDL] Winter & EVs

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Re: [EVDL] Winter & EVs

Hello Harsha,

I live in Montana, where it can get down to 35 below which my EV is design
for a 120 degree temperature difference. It takes a lot of equipment, and I
do not know if the E-beetle has the room or if it is possible to install a
heating system that can work with a on-board DC or AC system and a off board
pre heat heating system. My EV has both types of heating systems.

The first thing I do, is to insulated the garage walls to 64 R factor, the
ceiling to 120 R factor, and use a 19 R factor garage door with triple
seals. There is two small windows that face the sunny side, which is 5
layers of material which includes 2 panes of outside glass, 1 pane of inside
glass with a 6 inch air space, a horizontal insulated blind, and a vertical
blind, which is about 20 R factor and when its sunny, I have a heat gain.

On the ceiling, I have 24 large diameter 100 watt lamps even space through
out the ceiling which are control by six dimmer switches, a lighting
contactor and a room line voltage thermostat. There is a ceiling fan the is
also control by a built in thermostat if the ceiling temperature gets above
75 degrees.

On board the EV, I use three 120 vac heaters. These are under dash
convention air type with fans. The driver side is a 640 watt type, the
passenger side is a 840 watt and then under the front hood, there is a 1000
watt hot water heater with pump that is normally design for a semi truck.
This heats the water that comes from a holding tank made out of a 3 inch
diameter copper pipe that I had a radiator shop solder on a radiator cap.
This tank also acts as a expansion tank.

The water goes from the the heater, to a pump and to the existing heater
core and back to the tank and then to the heater. I found, that I only need
50 degree water temperature to keep my wind shield clear, because I block
the cold air ductwork that tempers the hot air from a engine, that could
reach over 200 degrees.

I use to have a Beetle at one time, which uses the hot air which goes
through a heat exchanger at the engine. If this is the case with your
Beetle, than you could install a underdash heater and tap into the heater

You could get by with one heater for direct convention in the driver
compartment and one for putting heat in the duct to keep your windshield

Anytime the outside temperature is below 30 and way down to -30, I preheat
the EV about 15 minutes before I go. I use a triple pole triple pole
switch, (three position ON - Off - ON) 30 amp rated to selected between the
on-board heater power, or out-board heater power which is tap off the 50 amp
main power plug with three 20 amp circuit breakers.

The garage with its high R-factor, the EV is mostly at a temperature of 70
degrees. The heaters preheat the EV for only about 15 minutes which will
raise the inside temperature to 80 degrees or more. When it was about 30
below, I could drive to my first destination, let it park for about an hour
and it may still be about 50 degrees inside.

Also the entire inside of the EV is insulation with 2 inches of blue foam
and cover with a marine carpet. The battery boxes are cover with 2 inches
of foam, a 4 inch air space, another layer of 2 inch foam with each layer of
foam cover with a marine carpet.

The insulated battery box is under a gold tint lean glass hatch back that
allows passive heat from the sun. At 30 below, during a sunny day, I had a
battery temperature of about 80 degrees.

The on board power to run these 120 vac 60 hz heaters, 120 vac pumps and
fans come from two sources. One from a solid state DC-AC inverter rated at
5 kw that comes off the main battery pack. Made by the Dynamote Co. The
other one is a alternator-inverter unit which can both provide 13.5 to 16
volts at 145 amps and at the same time provide 7 kw at 110 VDC which is then
inverted to 6 kw at 120 VDC which is also made by the Dynamote Co.

These later alternator-inverter unit, will not fit into a Beetle. I could
not use the inverter for this latter unit, because I did not have the room.

The advantage I have in using the alternator-inverter unit even its only 7
kw at 110 volts, It provides be with a braking regenerative when going on
icy roads.

You may even be able to convert a 120 vac 60 hz heater units by using the DC
power from the batteries just to the heater elements, but you will have to
change the fan motors to a 12 vdc source.


----- Original Message -----
From: <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, September 13, 2007 2:56 PM
Subject: [EVDL] Winter & EVs

> I am seriously considering buying a turnkey E-beetle from Utah. Since I
> live in
> the great white north (about 500 miles north of Lee:)), I am very
> interested in
> keeping myself & the batteries warm and functional. I sent an email to the
> Uth
> group and received no reply.
> My question is how do you keep yourself warm and still get 30 to 40 mile
> range
> per day. Or does on put the ev in the garage until the warm weather
> arrives?
> regards
> harsha godavari
> _______________________________________________
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