travel CPAP and power cunsumption

These are probably questions that have been asked and answered already but I have a different need, let me explain.

In a year my wife and I will Retire to a sailboat and begin cruising, I hope to eventually see the South Pacific. So we need if possible smaller machines (we both are using a CPAP, me an Auto, her a regular CPAP) hence the request for a travel machine recommendation, boat is not small, but not big either so a smaller machine would be very nice, but we will be living on it, so machine does have to last.

The electrical consumption isn't due to concern over a utility bill or anything as a CPAP is sort of trivial in that respect, but due to 100% of the electrical power we will use, I have to generate by Solar, an on-board generator and or the Alternator on the engine, storing it of course in a battery bank. You have to develop an energy budget of expected consumption, then build a charging system for that.
So I assume humidification is out due to power requirements, I could use an HME, but on the water maybe we don't need humidification. Ideally I'd like to find a machine that would run off of 13 VDC direct and not to have to have AC power, taking DC, converting it to AC so you can plug a power brick in and convert back to say 19 VDC is inefficient. Running one off it's internal battery is also inefficient as you have to recharge that battery and even having one with it's own Solar panel is less efficient than using the boats Solar system.
I have been looking at the Transcend, and the Z1. But have seen or touched neither, going solely on what I can find on the internet, neither is a 13 VDC machine, either would take a brick converter or similar.

Hi, can't imagine you'd need a humidifier on a boat, but if you eg. use A/C in the cabin it could be an issue I suppose. And while I appreciate the every-sq"-counts about boat living, the diff in sizes between one machine and another is really so small relative to anything - it's not as if you have to cram it in a carry-on that's being measured for flight. But I'll let others address the rest.

You might read up on what forum member CapnLoki uses as he lives on his boat for a good part of the year.
search.php?author_id=67433&sr=posts
Might have to read several to find his exact setup.

What brand cpap/apap are you using now?

a64pilot wrote:These are probably questions that have been asked and answered already but I have a different need, let me explain.

In a year my wife and I will Retire to a sailboat and begin cruising, I hope to eventually see the South Pacific. So we need if possible smaller machines (we both are using a CPAP, me an Auto, her a regular CPAP) hence the request for a travel machine recommendation, boat is not small, but not big either so a smaller machine would be very nice, but we will be living on it, so machine does have to last.

The electrical consumption isn't due to concern over a utility bill or anything as a CPAP is sort of trivial in that respect, but due to 100% of the electrical power we will use, I have to generate by Solar, an on-board generator and or the Alternator on the engine, storing it of course in a battery bank. You have to develop an energy budget of expected consumption, then build a charging system for that.
So I assume humidification is out due to power requirements, I could use an HME, but on the water maybe we don't need humidification. Ideally I'd like to find a machine that would run off of 13 VDC direct and not to have to have AC power, taking DC, converting it to AC so you can plug a power brick in and convert back to say 19 VDC is inefficient. Running one off it's internal battery is also inefficient as you have to recharge that battery and even having one with it's own Solar panel is less efficient than using the boats Solar system.
I have been looking at the Transcend, and the Z1. But have seen or touched neither, going solely on what I can find on the internet, neither is a 13 VDC machine, either would take a brick converter or similar.

I live on a sailboat in New England about 2-3 months every year (plus a few longer stretches travelling the East Coast) and use a PRS1 560. I stay entirely on a mooring or at anchor, so all power comes from solar or generator/engine alternator.

First point (and perhaps the most important): I have never used a humidifier or heated hose on board. I would have liked one on a few very chilly and dry fall mornings, but my bigger regret was forgetting the cabin heater! As a result, the power usage of my 560 is about 4 Amp-hours a night, which is small compared to my overall "juice budget" of about 70-80 AH. BTW, at home I always use humidity, but I've learned I can do without if the relative humidity is over 35% and there's no air conditioner running. Also, I usually don't bring it the humidifier when I travel to humid locations.

Second point: A key to enjoying the live aboard lifestyle is to have as many "normal" things as possible. You can use regular sheets on the bed, take hot showers, drink proper coffee, cook your favorite foods, etc. There will be plenty of limitations, so you shouldn't look for unnecessary ways to "rough it." and using a travel cpap to save a couple of ounces and maybe 1 amp-hour a day is one of those unnecessary thing. Get a proper pump to start with and you won't regret it.

I was briefly infatuated with the Transcend when I first learned I'd need a pump, but fortunately my DME gave me a Respironics which can run directly on 12V. When you look closely at the size and weight difference between that and the travel units, especially if you don't include the humidifier, there's really a very small difference that would only be noticed by someone trying to travel very light. There is a (mostly friendly) debate between Respironics and Resmed users as to the quality, but they're pretty similar with the nod going to Respironics for travel due to the 12V supply. ResMed does offer a 12-24V converter, but its an extra hassle best avoided. Since you and you wife both use a pump, you might consider getting 3 identical 560 autos so you'll have the same hardware plus a backup. This unit has recently been superseded so they should be easy to find on the gently used/grey market, and new 560 with BlueTooth is only $440 on our sponsor's site. I've never seen the newer units (or the new ResMeds) so I can't say how well suited they are to running on board or without the humidifier, but I haven't seen anything about them that would tempt me to upgrade. Perhaps others could comment on this point.

So I'm curious, do you have your boat yet?

CapnLoki wrote:[quote="a64pilot"

So I'm curious, do you have your boat yet?

Yes, I've had the boat for a couple of years, it's an Island Packet 38. I've installed 750W of Solar above the davits, but have two more 250W panels I could fit over the Bimini if I have to . I've installed a Nexgen 3.5 generator and a 660 Amp Hour Lifeline AGM bank, 140 amp Alternator and a 2800 W Magnum inverter / charger. Watermaker will wait until we leave. Boat was completely bare of systems so I've installed everything so far, she didn't even have Radar or windlass, autopilot, nothing. I plan on living and cruising on the "Hook", where I want to go Marina's are few and far between, but I am sure to keep the wife happy we will stay in them occasionally. I am not planning on "Camping", a few even tell me I'm going too far as I plan on unlimited water and power. First year I want to start out in the ICW and Caribbean making my way South through the canal and then jump to the Pacific
We currently both have PR system one machines. I'd like a travel sized machine if it meant we didn't have to give up anything except some cash, what are the drawbacks to a travel sized CPAP? For one thing, I want backup machines, if we have one break, it may be an extended time before we could get a replacement, so I plan on having back up machines and at least three months supplies on hand always. I've gotten CPAP dependent, meaning my sleep without one is horrible.

While I don't think a CPAP uses all that much power, you sure about the 4 AH? Way I do the math, assuming 8 hours, that is only about 6.5 watts, and I think they draw way more than that. I figure if each machine pulls 30W average for an 8 hr night, then that is 37 AH, which is a significant amount, but I do not truly know what they draw? My requirement is twice yours based on two machines


On edit, you and I appear to have the same or similar machines / mask

a64pilot wrote: Yes, I've had the boat for a couple of years, it's an Island Packet 38. I've installed 750W of Solar above the davits, but have two more 250W panels I could fit over the Bimini if I have to . I've installed a Nexgen 3.5 generator and a 660 Amp Hour Lifeline AGM bank, 140 amp Alternator and a 2800 W Magnum inverter / charger...

Nice boat - that should get you where you want to go. You'll have no problem with power, unless you have a walkin freezer.

a64pilot wrote: We currently both have PR system one machines. I'd like a travel sized machine if it meant we didn't have to give up anything except some cash, what are the drawbacks to a travel sized CPAP? For one thing, I want backup machines, if we have one break, it may be an extended time before we could get a replacement, so I plan on having back up machines and at least three months supplies on hand always. I've gotten CPAP dependent, meaning my sleep without one is horrible.

You can read the reviews here. While most people learn to love their PR or ResMed pumps, it seems like about half the reviewers don't like their "travel" machines. Too noisy is the biggest complaint, but some don't like the feel.

a64pilot wrote:While I don't think a CPAP uses all that much power, you sure about the 4 AH? Way I do the math, assuming 8 hours, that is only about 6.5 watts, and I think they draw way more than that. I figure if each machine pulls 30W average for an 8 hr night, then that is 37 AH, which is a significant amount, but I do not truly know what they draw? My requirement is twice yours based on two machines

Your numbers are high, even for humidifier and hose.

Here's the data:
viewtopic.php?t=102179

I'm real familiar with a Watts up meter, I use one on my Silent Submersion Scuba Scooter.
I think you are doing something wrong, 4 AH, assuming for 8 hours is of course a current draw of only .5 amp.
.5 amp at 12V is 6 watts. Now I can't find data for our machines (we have the same one) but for the Z-1 travel machine the current draw is 20W typical, 35W max, seems most manufacturers don't give a power consumption and for the typical user, it's so low as to be irrelevant
https://www.cpap.com/productpage/z1-aut ... #specs-tab
I had assumed a machine designed to be run off of a battery would be very efficient, but maybe not.

I'm in the middle of moving, but once moved and once my power cord arrives I may hook up my watts up meter for a check myself, 6W is a very low power consumption, one little RV / boat light (tail light bulb) is 12W for comparison. I hope your right, because if you are, then 12W for two machines is not an issue for me at all, fridge draws 5 amps ( 60W) and runs pretty much continuously 12 more watts is a drop in the bucket

Hard to believe that our machines are 5 time more efficient.

But I've decided largely based on being able to run off of 12 VDC directly to get the 12V power cords for both my Wife and my machines, as you say they aren't really that big, I have supplies for them already, they are available on the used market etc., no need for a travel machine I guess, I just got enamored with the idea I guess.

Sorry about the delay, I'm travelling now, tablet bound. My numbers are good, verified by many reports of battery usage. Also, look for "resmed battery guide pdf" and you'll find the s9 draw at 0.55 amps for pressure 10.
Also, note that your machine (without humidifier) runs stone cold, if it wasted even 10 watts you'd feel the heat.
When I get back I'll get into more detail.