Greg Potts wrote:
> Hi Mike,

> It's not going to work. You can't extract enough energy from a 12V
> battery to heat 180 cubic feet of Vanagon interior. Your alternator
> could not keep up with the draw, either. It's basic physics, and the
> question has come up on the aircooled list every fall since the lists
> started.  If it was practical, automotive engineers would have
> adopted electrical heating a long time ago.

> There are tiny little 12V hairdryers that are popular for defrosting
> bus windshields, but they don't supply enough heat to warm the
> interior of a bug.

> The best approach for electric heat in a vehicle is to wear heated
> clothing. That might not be as convenient, but it will work.
> http://cozywinters.com/heated-clothing/?
> source=go&gclid=CMSk6eXm4ogCFSLrPgodnGpapQ

While my original post mentioned my questions of the amount of amps
being drawn being too much, I'm not certain that would make this scheme
unworkable.

---

How did the heating systems work in all electric vehicles like the GM
EV1 or the other prototypes tried by Toyota and others in the '90s?

I've also recently noted a new all electric arrival that isn't shipping
yet...range of more than double the GM EV1 so it's more than practical
between charges for local uses:

http://www.teslamotors.com/

There must be some electric heat production method here and it couldn't
be eating amps at the expense of serious range.

---

In the Vanagon's case, and you were running it off an aux. batt. maybe
there should be an external charging connection and some circuitry to
run an 'empty - full' gauge along with an auto shutoff so it doesn't
kill the battery dead.  That way, you'd have an idea of when you should
use it, how long it would last and be able to plug in your charger when
you got home.  It might not be perfect but it would be something.

--

Wil