Steve is right. Even if you are able to run it for a couple of minutes, = you won't be able to continue charging the battery with that kind of current = draw.  Of course, you could consider a second alternator (not!). 
 
wade
 
PS, there's a company called dongfar that makes a 12v 1300btu AC = system.  They claim something like 300 watts of power usage.  This may be more = doable, but I haven't ground through the math.
-----Original Message-----
From: Vanagon Mailing = List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf Of Steve Sandlin
Sent: Friday, August 03, 2001 10:20 AM
To: = vanagon@GERRY.VANAGON.COM
Subject: Re: insane AC idea

I also use a small window AC in my westy, but only while = camping.  It mounts in the drivers window.  I think you have overlooked a = major problem in trying to use the unit while operating...power.  = Though the inverter is heavy enough to handle the A/C, you can't supply enough 12 = volts to the battery/inverter to keep the battery charged, not to speak of = running the van itself, plus lights, radio, etc.  If the A/C pulls 10 = Amps at 120V, that's 1200 Watts.  Assume 75% effeciency on the inverter = (that's optimistic) and you'll find energy useage of 1500W.  A 70 Amp = Vanagon alternator at 12 volts supplies a maximum of 840W, barely half of what = you need just for the A/C.  Where is the rest of the power coming = from?  If you are depending on the battery to supply it, you'll be in a dead = battery state very shortly, not to speak of decreased altermator life while = running it full tilt for extended lengths of ! time.  The power just isn't there...run the numbers.
Steve Sandlin
'84 Wolfsburg Westy
'79 Bus
'00 New Beetle


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