Date:         Fri, 30 Jan 2009 11:17:43 -0500
Reply-To:     Mike S <mikes@FLATSURFACE.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mike S <mikes@FLATSURFACE.COM>
Subject:      Re: 12V power inverter ?
Comments: To: Michael Sullivan <sandwichhead@GMAIL.COM>
In-Reply-To:  <eccfedcc0901300710u4cf5f20dm9775d9d58c0dd6b7@mail.gmail.co m>
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At 10:10 AM 1/30/2009, Michael Sullivan wrote...
>That's what I'm hearing.  What kinda of jack am I looking at in order
>to do
>this?  Extra battery and setup, also?

A 500W "modified sine wave" inverter can be had for <$100, but I can't
guarantee it would work. A true sine wave inverter would run in the
$200 range.

Assuming the big printer averages 200W draw (average between
idle/printing),

A group 27 battery has about 100 AH of capacity, but that effectively
goes down as current draw goes up. 200 W = 12v * 16.7 Amps. But
inverters aren't 100% efficient, so maybe a 20A draw on average. That's
a 5 hour discharge rate, but due to inverter inefficiency and the
relatively high load, probably 2-3 hours max.

I'd try the smaller printer with your existing inverter. At 34W
operating, you should be able to get a full day's worth of printing
from a good condition, fully charged, group 27 battery.