2619, Designs for Review (with questions).

[Riwright]

Calculations for your CPAP are probably off. If you get a Kill-A-Watt meter you can hook it up and start to get a window into how much power the thing actually uses.

If you have a heated humidifier it will use a much greater amount of power than the blower alone. Don't experiment with the blower settings, but you can experiment with the humidifier. Set the humidity as low as you can and still keep from drying out. You can save a *lot* of power that way.

Most manufacturers make a 12 volt adapter for their machines. If they do, then get one. It will save you the losses that you get from an inverter. A "Watts Up" meter is very useful for keeping an eye on 12 volt power consumption.

I found that voltage drop is a problem with these machines. I made my own extension cord using 10AWG wire and it cleared up a lot of problems for me. I have not found a pre-made 12 volt extension cord with a heavy gauge wire.

[rickst29]

and that is high humidifier (heat + less efficient air path) with a high pressure setting. It has 5 pressure settings, but I do quite well with the pressure setting down at "2".
{SNIP} ... I've found a module which will (probably) do what I want. I've created a New Thread for running CPAP at +12V in 'Electrical', here