I kind of figured that this stuff would be documented. It's a medical device so documentation abounds. Supports my theory that they vary widely in power requirements. Great find!
The Resmed AirSense 11 AutoSet CPAP is their current and probably most popular model. It isn’t listed in this guide (The guide is from 2018). The Resmed AirSense 11 has different power requirements than all the other models. It uses 24 Volts DC and 2.71 Amps. It also uses a proprietary connector. Apparently Resmed does not (yet?) offer a DC to DC adapter for this machine but there are several brands being offered on Amazon specifically for this use.
The stock AC to DC converter that comes with the AirSense 11 is 65 watts and the aftermarket DC to DC converters are also 65 watts. I can't speak to the actual power usage.
So if we accept a worst case of 65 watts for 10 hours, that’s 650 watt-hrs. A 100 Amp-hr FLA battery has around 1,200 watt-hrs of energy, but you should only discharge it to 50% State-of-Charge, so that’s 600 Watt-hrs. Now power that 64-watt power supply with a 120-volt AC inverter that has 90% efficiency but also uses 30 watts of overhead for the fan and control electronics, and you’re well over 100 watts needed from your house battery. That’s 1,000 watt-hrs (1 kWh) of energy for 10 hours.
Of course these are just my guesstimates based on other systems I’ve tested in my FunkWorks Lab, but I’ll bet I’m not far off. We shall see once I run some tests on a CPAP machine.
I need to test, but I’m reasonably confident a CPAP will use twice that amount of power from your RV battery if you connect it to a 120-volt AC inverter. Powering from 12-volts DC using their 12/24-volt adapter is probably the most efficient hookup. But I need a demo unit to measure.
Great info. I kind of figured this out and just spent 3 weeks running an air mini off my boat batteries, using their dc to dc converter, that are charged by a solar panel. The boat was only run every 5 days or so. I have no doubt that my RV will be the same
Mike, K slayter here - hope to see you at FROG - I bought two dual fuel champion generators, -one will start my AC but the store manager suggests i keep the second as it only pulls 15 amps with one and I have a 30 AMP coach. I have the parallel kit - for second generator. when it cranked the AC with Soft Start, 15000 coleman macRunning it got really loud. can just one can cause issues with my electrical? Not sure I understand - I will keep the second one for now and maybe when i see you at FROG I will understand better why this is advised. The store was willing to take the second one back, 2500 watt inverter and I tested it on Propane. It is dual fuel. On propane with normal load running aC the one generator is supposed to last 20 hours with a 20# tank. As you can see I am confused - I will have to use it to understand the ratios etc more completely.
I kind of figured that this stuff would be documented. It's a medical device so documentation abounds. Supports my theory that they vary widely in power requirements. Great find!
This is important documentation that each of you should share to your other groups. This is exactly the kind of chart that we need.
A nice find. I found that I already have this document on my PC saved from 8/2022
The Resmed AirSense 11 AutoSet CPAP is their current and probably most popular model. It isn’t listed in this guide (The guide is from 2018). The Resmed AirSense 11 has different power requirements than all the other models. It uses 24 Volts DC and 2.71 Amps. It also uses a proprietary connector. Apparently Resmed does not (yet?) offer a DC to DC adapter for this machine but there are several brands being offered on Amazon specifically for this use.
More to test. I’ll ask ResMed for an AirSense 11 to demo…
The stock AC to DC converter that comes with the AirSense 11 is 65 watts and the aftermarket DC to DC converters are also 65 watts. I can't speak to the actual power usage.
So if we accept a worst case of 65 watts for 10 hours, that’s 650 watt-hrs. A 100 Amp-hr FLA battery has around 1,200 watt-hrs of energy, but you should only discharge it to 50% State-of-Charge, so that’s 600 Watt-hrs. Now power that 64-watt power supply with a 120-volt AC inverter that has 90% efficiency but also uses 30 watts of overhead for the fan and control electronics, and you’re well over 100 watts needed from your house battery. That’s 1,000 watt-hrs (1 kWh) of energy for 10 hours.
Of course these are just my guesstimates based on other systems I’ve tested in my FunkWorks Lab, but I’ll bet I’m not far off. We shall see once I run some tests on a CPAP machine.
I need to test, but I’m reasonably confident a CPAP will use twice that amount of power from your RV battery if you connect it to a 120-volt AC inverter. Powering from 12-volts DC using their 12/24-volt adapter is probably the most efficient hookup. But I need a demo unit to measure.
Great info. I kind of figured this out and just spent 3 weeks running an air mini off my boat batteries, using their dc to dc converter, that are charged by a solar panel. The boat was only run every 5 days or so. I have no doubt that my RV will be the same
How much solar and batteries did you have?
40 watt solar panel
House batteries are 2, 12V, 105 Amp each
Mike, K slayter here - hope to see you at FROG - I bought two dual fuel champion generators, -one will start my AC but the store manager suggests i keep the second as it only pulls 15 amps with one and I have a 30 AMP coach. I have the parallel kit - for second generator. when it cranked the AC with Soft Start, 15000 coleman macRunning it got really loud. can just one can cause issues with my electrical? Not sure I understand - I will keep the second one for now and maybe when i see you at FROG I will understand better why this is advised. The store was willing to take the second one back, 2500 watt inverter and I tested it on Propane. It is dual fuel. On propane with normal load running aC the one generator is supposed to last 20 hours with a 20# tank. As you can see I am confused - I will have to use it to understand the ratios etc more completely.
I’ll see you at FROG. I’ll be there Mon, Tues & Wed…