20 Comments
author

I’ve previously asked ResMed to send me a CPAP unit for testing, but I never heard from them. Nobody in my family uses one so I have nothing to test.

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Probably not going to happen as they require a prescription. Also they are in short supply right now due to the settlement of a lawsuit which required one of the major players to replace a bunch of units

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No, the third sentence states: "Last night over 8 hours it used 1.170 KWh with a maximum draw of 1473 W at 119.6 VAC. " He states he had a maximum draw of 1.473Kw.......no? Doing the math on that would be 1473W/119.6V = 12.32 Amps......nearly as much as a floor heater......no way!

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author

That 1.473kW must be a measurement error. This is why I want to measure these things for myself.

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From my wife's ResMed 'brick'

Model 390000 65W AC ADAPTER

Input 100-240V ~ (AC sine wave) 2.0A 50-60Hz

115V ~ 1.5A 400Hz

Output 24V DC 2.71A

I use the Philips brand CPAP, have 5 of them, the biggest 'brick' has 80W empossed/molded into the plastic case.

Ain't no way that guy was pulling 1Kw+

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author

He said kWH not kW. So even 80 watts x 10 hours would be 800Wh or 0.8kWh.

Interestingly, ResMed is considering sending me a demo unit to test. We shall see…

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It is definitely worth the investment in the dc to dc power supply if you have a way to connect it to dc power in your rig.

Converting dc to ac and then back to dc is inefficient and will run your batteries down much faster.

I use a small portable flash fish lithium battery with my air sense 10 and recharge it after 2 nights.

I do not use the humidifier. I do have the cover for my hose to insulate it for more consistent temperature and less condensation.

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I use the same unit with a 12v cord connected to a GoalZero 500 battery. With no heat, it uses about 10% of my battery. I also use a 200w foldup solar panels to recharge my battery when I am camping.

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WOW! The heater really draws a lot of power. I posted my results earlier (No heater) and if memory serves me it was only drawing 8 watts. The brand new ones are much more complex and even have cell phones inside them to call "The Mother Ship" periodically for data downloads and updates.

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author

Yup, heaters take a lot of energy to run.

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I looked at my power supply which is designed to run my CPAP with a heater, even though I do not use the heater. It is rated at :

Input 1.2 Amps @120v and Output 4.2Amps@12v These are the UL max numbers on the converter and is nowhere near the numbers stated by the user quoted in the article. I am not doubting their number but, It seems that these devices vary widely in their power consumption and maybe it would be more prudent to make individual recommendations rather that just telling folks that they need to buy 200AH as a blanket statement. I had 200AH in my last truck camper. I could microwave dinner, run CPAP and an electric blanket all night and still have plenty left to make a pot of drip coffee in the morning.

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author

It all depends… But the only way to know for sure is to gather empirical data from actual testing, and I am getting similar reports from readers who are using a Kill-O-Watt meter to measure actual kWh usage overnight.

Note that I wrote that a single 100Ah Lithium battery would power that CPAP unit, but they would have no battery charge left for anything else. That’s why I recommended at least 200Ah of battery for this application.

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Mike, I use the same machine as Bill. Wonder what heater setting he’s using as it may impact the energy consumption. The heater setting was specifically mentioned. Here in the Central Valley of CA I have mine her at 6 as the humidity is low during the hot summers.

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The setting WASNT mentioned.

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Wow ! This really SUCKS ! I have a DreamStation CPAP Machine - BY PHILIPS RESPIRONICS Item #DSX200S11 An 80 watt brick. ( Output is 12 volts at 6.67 amps max. ) 12 volts helps avoid a DC-DC converter.

I used it 3 nights on #3 heater setting. With my 300 Ah lithium battery. It would probably go a week without the heater. ( Battery is EXP96 Pro Lithium Iron Phosphate Battery Bank )

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author

Hey, I don’t make the news. I just report it! 😁😁😁

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Great info Mike. I use this same cpap brand so this infor is relevant.

Can you suggest an independent circuit setup that would be used specifically for the CPAP?

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author

Working on it. That’s why I’m asking ResMed for a test unit…

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I also have a ResMed 10 CPAP. Using my Kill-O-Watt meter I measured a couple of nights usage with the heater & humidifier on at home. I haven't used it in my motor home yet.

First night it showed 0.20 KWH for 11 1/2 hours. Second night showed 0.27 KWH for 12 hours.

All settings are on Automatic. Daytime with no usage showed 0.10 KWH for 12 hours. In use the meter shows around 0.3 Amp & not used shows 0.05 Amp.

Nameplate says 24 Volts @ 3.75 Amp

My motor home has 6 lead-acid size 24DC batteries in parallel with 2 100 watt solar panels and a power converter 12/120 Volt.

We've also installed a heated bidet seat on the toilet.

Ken Idaho

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Direct experience. Both wife and I use cpaps. In RV I have two renogy 100 amp LiFePo4 batteries ( w/o heaters - I do have degraded cold weather performance, as at Yosemite). Overnight we get down to 60% capacity but on sunny days back up to 100% by 11:00 with 4 100w panels. Settled on 50amp Dc-Dc charger. Set up works great and my starting battery stays topped up too. I do use humidifier and heated hose.

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