by eamarquardt » Thu Dec 13, 2007 12:36 pm
Hi,
Jumping in here a the end I'm not sure exactly what your need is. It sounds like your girlfriend has a breathing machine she uses when she sleeps that draws about 200 watts at 120 volts and needs a nice sine wave to work correctly (I absolutely agree that all inverters are not created equal).
Depending on the efficiency of the inverter I'd guess will take about 20 dc amps at 12 volts to create 200 watts at 120 volts ac. Guessing that your girlfriend will like to sleep for about 8 hours that will be about 160 amp hours. Having some experince managing 12 volt useage on a sailboat with no access to ac suggests that 160 amp hours is a lot. Under the best of circumstances it would take a 60 amp alternator about 3 hours to pump that must oomph into a bank of batteries (don't quote me on this, but it's a place to start your thinking).
So, what's my point. You need to think about the whole system before buying anything. Several batteries will be required, a big charger, and a good inverter.
Not to be a "Gloomy Gus" but I sometimes find myself admiring my beautiful paint job from the corner I've just painted myself into.
Hope this helps.
Cheers,
Gus
The opinions in this post are my own. My comments are directed to those that might like an alternative approach to those already espoused.There is the right way,the wrong way,the USMC way, your way, my way, and the highway.
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