For best efficiency, the inverter should be somewhat matched to the total load expected. About 80% of the inverter rating is ideal. next issue is battery capacity. The inverter size should be limited so your battery can support it for ~ 5-6 hours. Drawing off the battery at a higher rate will damage the battery. A 1200 watt inverter needs over 120 amps to support it. You will need 3-4 optimas to support that load. A 300 watt inverter needs 30+ amps which will still kill that battery in ~2-3 hours. That would be my recommended limit. You will then need to drive for ~4-6 hours to put that charge back.

Dennis

----- Original Message -----
From: Chris Paquette <chris.paquette@GMAIL.COM>
Date: Wednesday, August 18, 2004 4:09 pm
Subject: General Inverter Questions

> Considering adding an inverter to the dual battery setup in my '88
> Westy. I have my eye on the Coleman Powermate 800. I have a couple of
> general questions:
>
> 1.) Is an inverter on all the time if connected to my second battery,
> or do they generally have an on/off switch? The concern here is that
> if it's on all the time, the inverter's cooling fan (if any) might
> come on intermittently during the night when I'm trying to sleep.
>
> 2.) Power consumption is dictated solely by what is connected to the
> inverter, and not the wattage of the inverter itself, correct?
> IOW, a
> Powermate 1200 won't drain my battery any faster than a Powermate 800
> if they each had the same items attached to them, correct?
>
> 3.) Any problems/issues with permanently mounting an inverter to
> either side of the stove? Seems like that would be an ideal place to
> plug in the laptop, cell phone, etc.
>
> 4.) Finally, would the secondary battery (Optima deep-cycle marine)
> last long enough, assuming fully charged, to watch a long-ish
> (say, 3
> hour) DVD?
>
> Thanks for any help,
> Chris
> '88 Westy, "Rocinante"
>