Need AC for cpap

[Ken K.]

Originally Posted by aeblank

I don't understand disconnecting anything or completely separate batteries that have to be taken care of. Use a DC plug or worse a small inverter. Know ahead of time how long it'll run the machine. Increase coach battery bank as required.

exactly..

[dalford]

I just went through this as I am about to boondock this week at a Harvest Host and I use a cpap. I have a Resmed Airsense10 so I bought this DC to DC converter. My cpap is also 24dc input.

https://www.amazon.com/Converter-Air...0+dc+converter

I then upgraded my batteries to 6 volt golf cart deep cycle batteries like Trojan 105 series. These connected in series will supply 225ah at a 20 hour rate.

This kit comes with a 12volt adapter that alligator clips to the batteries. My batteries are just below the bedroom slide so I took a strip of Velcro and attached it under the slide and the other strip of Velcro to the converter. I attach the converter there and then retract the bedroom slide a few inches so I can slip the cpap 24vconnector between the slide and the wall into the bedroom. I then close the slide. I found that this did not crimp the cable and I am able,to slide it in and out with little effort.

Don't know what model your cpap is but just google your make and model number along with the words dc converter.

Hope this helps

[OldBob]

Originally Posted by Willyt

Hello, this is a first time post so please forgive my mistakes. We are going to a campground that does not have AC and you can not run generators after 10:00 PM, but I need AC to run my cpap machine. So here is my idea, I have dual batteries on my trailer. Option 1 is to disconnect one of my batteries from the trailer and leave one connected to supply 12 vdc to the trailer. I would connect a 1000 watt AC inverter to the to the battery I had previously disconnected and take the output of the inverter to my trailer's AC input. I would rechsrge the batteries the next day with my generator. The other option is to disconnect both batteries from the trailer and connect them to the AC inverter and connect the output of the inverter to the trailer AC input and charge with the generator the next day. Let me know what you think about these ideas.

My wife has a full size CPAP with the water module and we used to run her machine with a tiny 150 watt inverter. The CPAPs don't use much power. If you have a 12v accessory outlet in the trailer just pick up a small inverter and you should be all set. If you don't have any 12v outlets they are very easy to add to the trailer. 12v wires are everywhere inside, easy to tap into.

[Grumpy7159]

I bought an adapter kit for my CPAP for $59. It hooks up to the battery with large alligator clips and has a cigarette connection between the battery and the CPAP. I use a spare battery next to my bed and do not use the humidifier or heated hose. Seems to work well so far. I recharge the battery off my generator, but I am looking at a solar option.

[aeblank]

Why a separate battery? Add it to your bank and it's all taken care of.

[RadRik]

Originally Posted by sasch

I was fortunate that Rockwood installed a 12V (cigarette lighter type adapter) connection alongside my bed - with the optional adapter & AC/DC converter for my cpap I can plug into that and draw off my camper battery. I shut off the heated hose and humidifier to lesson the drain on my battery unless connected to shore power.

X2 I hook mine into the 12V adapter with a cord I got online that fits into the back of my CPAP hookup.

[bend302]

I have a CPAP and bought a battery booster at WalMart for around $120 that has a built in inverter as well as a 12V outlet. I have used it a couple of times and it works great. Overnight it uses about 15% of capacity.

Plug into any AC outlet to recharge.

Bill

[Alben]

I am surprised how many people here say their CPAP is 24V. I am an electrical engineer, so here is my take on using an inverter: Most 12VDC to 110VAC inverters are about 80-85% efficient. Then the 110VAC to DC brick adapter supplied with the CPAP itself is an 80% efficiency rating. In other words, using an inverter in combination of the factory DC brick of the CPAP, you are probably losing about 40-45% of your available battery power with the two conversions. This is significant, almost 1/2 of your battery life is wasted.

My CPAP is able to run on 12VDC directly with a cigarette lighter to 12VDC barrel plug cord. This makes it the most efficient use of battery power, as there are no power conversions. My camper originally did not have a 12VDC plug by my bed, so I put one in. The humidifier consumes a lot of current, so I don't use the humidifier when camping.

When shopping for a new CPAP, make sure it can run on 12VDC.

[dalford]

Originally Posted by Alben

I am surprised how many people here say their CPAP is 24V. I am an electrical engineer, so here is my take on using an inverter: Most 12VDC to 110VAC inverters are about 80-85% efficient. Then the 110VAC to DC brick adapter supplied with the CPAP itself is an 80% efficiency rating. In other words, using an inverter in combination of the factory DC brick of the CPAP, you are probably losing about 40-45% of your available battery power with the two conversions. This is significant, almost 1/2 of your battery life is wasted.

My CPAP is able to run on 12VDC directly with a cigarette lighter to 12VDC barrel plug cord. This makes it the most efficient use of battery power, as there are no power conversions. My camper originally did not have a 12VDC plug by my bed, so I put one in. The humidifier consumes a lot of current, so I don't use the humidifier when camping.

When shopping for a new CPAP, make sure it can run on 12VDC.

I guess most of us didn't plan ahead for boondocking when we purchased our cpap. Actually, I was prescribed a cpap by my pulmonary doctor.

Anyway. I did not plan ahead and mine is 24 volt so I need to deal with that so I bought the brick So I'm not loosing 40% but only 20% but it probably doesn't matter much because they don't draw that much power even with humidity.

Below is an attachment of the current required with a 50% safety margin of the cpap I use.... I don't need humidity but if I did it looks like I would need a battery to supply 50ah over 8 hours..

Now, next purchase I will look to get a 12volt model..

[Bama Rambler]

Most Resmed units run on 24 VDC.
If you look on CPAP.com, they tell you which units will run on 12 VDC using just a power plug and which ones you have to have an adapter for (either ac-dc, dc-dc or dc-ac).

[rockfordroo]

Originally Posted by YoBobH42

First off, I have a CPAP and we do a lot of dry camping and this is something that can be worked out inexpensively. A deep cycle 12V battery is the start, and you can get one at Advance for like $100. Next is a 12V to 110 inverter (actually it is more like a converter but it is called an inverter). You can get one of these, inexpensively at Northern Tool ($10-12 when on sale). I prefer the alligator clip ones. This is all you basically need.

An inverter is NOTHING like a converter, except for the fact that it "changes" something and it's usually in a "box" of some kind.

An inverter changes 12VDC to 110VAC.

A converter changes 110VAC to 12VDC.

[hilfikerkg]

Originally Posted by aeblank

Why a separate battery? Add it to your bank and it's all taken care of.

CPAPs seem to be more sensitive to voltage drop than LED lights and Slide out motors.

[Alben]

Took some amp readings this weekend to find out how much power a CPAP uses.

Philips Respironics Remstar Auto A-Flex.
12VDC input direct through cigarette lighter cord.
CPAP not running, but plugged in: 100mA
CPAP free running - not placed on face: 2,200mA
CPAP in use on face: 500mA

[aeblank]

500mA seems pretty good to me (not that I know diddly).

[dbledan]

Originally Posted by Alben

Took some amp readings this weekend to find out how much power a CPAP uses.

Philips Respironics Remstar Auto A-Flex.
12VDC input direct through cigarette lighter cord.
CPAP not running, but plugged in: 100mA
CPAP free running - not placed on face: 2,200mA
CPAP in use on face: 500mA

That is not with the heater running correct?

[Bama Rambler]

Do you know the vent flow for the mask you were using during the test?

The reason I ask is that a mask with a higher vent flow will cause the unit to draw more current. A small amount probably won't make much difference, but going from a nasal mask to a large full face mask probably will.

[rockfordroo]

Originally Posted by Alben

Took some amp readings this weekend to find out how much power a CPAP uses.

Philips Respironics Remstar Auto A-Flex.
12VDC input direct through cigarette lighter cord.
CPAP not running, but plugged in: 100mA
CPAP free running - not placed on face: 2,200mA
CPAP in use on face: 500mA

500mA is 0.5A. Same draw as the Dometic fridge door heater.

[Alben]

Readings were taken with no humidifier heater.

A nasal mask was used.

Sorry, I don't know the vent flow.

When inhaling, the current increases, and when exhaling, the current decreases. 500mA (0.5Amp) was the average reading.

[Bama Rambler]

A full face mask will probably raise the average draw a little, but will probably stay well below 1 amp.

[Skyliner]

Wife just got a CPAP and I just installed a 10 amp 12 volt DC to 24 volt DC converter instead of leaving our 1500 watt inverter on all night.

I cut her CPAPS's 24 volt power line and installed 2 prong aviation plugs and installed the 24 DC aviation plug next to her side of the RV bed. Took me about a beer' worth of time to do the job.