Any Boaters Out There??

EdAPAP · Post by **EdAPAP** » Sun Dec 02, 2007 9:29 am

Any boaters out there who use CPAP with DC power?

We have a small trawler (no generator) and often spend the night at anchor with only 12V DC power.

Is the Respironics DC power cord safe and sufficient for CPAP?

Or, is a pure sine wave inverter recommended?

Ed

mindy · Post by **mindy** » Sun Dec 02, 2007 11:18 am

Hi Ed,

I don't know the answers to your questions but do recall seeing some threads on that. The two below are more about camping and power outages but may provide some help.

viewtopic.php?t=4049

viewtopic.php?t=15878

In addition, in case you haven't seem one of RG's posts about how to search cpaptalk.com more easily, use google as follows:

search terms site:cpaptalk.com

e.g. boat cpap site:cpaptalk.com

Mindy

Bearded_One · Post by **Bearded_One** » Sun Dec 02, 2007 12:58 pm

A Respironics 12 volt cable is proper and safe to use, and can be used as a permanent power supply for your Respironics auto M CPAP. I notice that you use a passover type humidifier, no power is required for the humidifier.

If you were to use a Respironics series M heated humidifier you would need a standard modified sine wave inverter -- it does not have to be pure sine wave.

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, humidifier, CPAP, Power, auto

EdAPAP · Post by **EdAPAP** » Sun Dec 02, 2007 1:53 pm

Thanks, Bearded One. Actually I do have the M Series heated humidifier, so I would need an inverter. It might be simpler to leave the humidfier at home when we spend a weekend on the boat???

On the other hand, it might be useful to have an inverter so I can use the humidifier and my laptop to see the Garmin MapSource charts in a format larger than the chartplotter.

The inverters' specs indicate that some medical device manufacturers recommend a pure sine wave inverter.

1. What is the difference between a modified sine inverter and a pure sine inverter?

2. How much battery drain would an inverter AND a CPAP on a boat's battery?

Ed

WNJ · Post by **WNJ** » Sun Dec 02, 2007 9:19 pm

Ed,

I’ve been perfectly satisfied with using the Respironics DC cord with my REMstar Auto. I would expect the same result with the M Series.

I use my humidifier as a passover and it has been perfectly satisfactory. Odds are that the air in the cabin of your boat is more humid to begin with compared with the air in your bedroom.

As to your questions:

“What is the difference between a modified sine inverter and a pure sine inverter?”

A pure sine wave would produce a flow of electricity that looks like a smooth sine wave curve. A modified sine wave is a lumpy, not smooth, curve. The Respironics humidifier does not require a pure sine wave inverter or generator for power. Check your owners manual. (The ResMed machines do require the much more expensive pure sine wave inverter.)

“How much battery drain would an inverter AND a CPAP on a boat's battery?”

Inverters are very inefficient. Notice the cooling fins on an inverter? They are there to dissipate the heat which is necessarily “wasted” in the conversion process. If you have a convenient way of recharging your batteries every day, this inefficiency will probably matter little, if at all.

If you’re going to use your laptop with the inverter, you may need a pure sine wave inverter. Check your laptop’s manual.

I suggest you try your machine with a Respironics DC cord, using the humidifier as a passover, before going to the trouble and expense of an inverter.

Wayne