I tried several different search criteria, but had little luck, so I'm posting here.
I've got a PR REMStar Auto A-Flex Series 60 CPAP machine and need some info on actual Amp draw (without the humidifier).
I did find an older thread from 2011, or so, with some great information, but the CPAP model, and Amperage of that model, was different than mine, so I wasn't sure how accurate it was.
Like many members I've seen, I'm trying to build a solar array and house-battery power source for my camper-van, but I can't even get started until I figure out how many Amps my system draws.
Unfortunately I don't have a Miliamp meter, or I wouldn't be here asking you kind folks this otherwise easily answered question.
On the bottom of the machine it says 12 Volts/6.67A (that seems very high!), but from what I've been reading, that doesn't mean that my A-Flex will always, or ever, draw that many Amps. Especially since I'm not running the humidifier and use a fairly low setting (6).
Does anyone here have this model and have real-world experience testing the Amp draw? I need to know how small of a solar panel and AGM battery combination I can get away with. My van is quite small, so the less I need the better.
Basing my needs on the 6.67A, I'd need a huge battery (100Ah-!50Ah) and way too many solar panels, which is a problem because space is limited.
If, on the other hand, my system only draws 1 or 2 Amps, I can get away with a much smaller AGM battery and perhaps a single, 100 Watt panel, which would make me VERY happy. :grin:
I know just about everything I need to when it comes to solar panels, charge controllers and AGM batteries, but until I figure out my machine's requirements, I can't "pull the trigger" on this project.
Sorry this was so long-winded.
05-10-2015, 11:08 PM
(This post was last modified: 05-10-2015, 11:11 PM by krelvin.)
Don't know the answer but do know that an AGM 35 Amp-Hour system will run a PR Series 60 unit using a battery cable for almost a week with no humidifier.
You would want to find out what the requirements are when running off the battery cable, not off of AC using the power brick for a better idea.
A Resmed will not last as long as they need a converter to get the 24V needed by the unit (DC).
As for charging, you would only be using the CPAP at night, so charging would be done during the day and normally you would be adding to the reserve not starting over every day.
I have a solar system at my place up in Chino Valley, but I didn't put it together so I don't know what the numbers are. It is used for TV, lights (LED) and other uses on top of CPAP but I only use it a couple times a year for a day or two. Next time I am up there I will get a copy of the details.
I've never had a shortage of power while there yet.
05-11-2015, 05:45 AM
(This post was last modified: 05-11-2015, 06:08 AM by iSnore.)
12 volts x 6.67 amps = 80 watts. That's the rating of the power supply that comes with the heated tube humidifier. The one that comes with basic machine for use with the unheated tube humidifier is only rated 60 watts, meaning 5 amps max.
Here's the ResMed Battery Guide
. Look at the numbers for the AirSense 10, without humidifier in use. While it's not the same device, it's doing the same work with the same type components. Note that as the pressure increases, so does the current draw. As mentioned above, the ResMeds use a DC-DC converter which are a bit less efficient. In short, your estimate of 1-2 amps is probably ballpark.
edit to add: IMO an amp-hour meter is a critical component of any RV/marine battery system. It integrates the current through a shunt over time in both directions--both charging and discharging from the battery bank. I highly recommend it.
Are you running it at a strait pressure of 6 cm H2O? If you run it in auto mode, what is your max pressure and 90% pressure? I figured mine at a pressure of 11 (which is usually my 90% pressure - average is around 9) - I did the testing and figured I can safely get more than 5 sleep-nights out of a 35 AH battery with no heated humidifier, just like krelvin said... If you are running a straight 6 cm, you should have no trouble making a week.
Let me know if that doesn't do it for you. If you really really need it, I could set mine up like that and run it for an hour or two while watching TV and let you know what amp draw **I** score. Your number would still likely be different in that you and I probably don't have the same breathing patterns, but I am betting it would be close. I truely wish that Repsironics would publish a battery use manual like DeVillbiss and ResMed do. It would be a great service to users.
I just got off the phone with both Supplier #1
and PR. CPAP couldn't answer my question, but they gave me a contact number for PR, where I got the answer I needed and, given what I've been reading on this site, expected to get.
The guy I spoke with said that 6.67A is the maximum amperage the unit would draw with the humidifier attached and that 2.0 - 2.2 Amps would be the average Amp draw I could expect without the humidifier or heated hose. They quote 3 Amps just to be safe.
This is a HUGE load off my mind as for the past few months I feared I wasn't going to have room for the necessary number of solar panels and that I'd need a super-heavy battery.
3.0 Amps X 8 hours of sleep per night = 24.0 Ah taken from the battery each night. Going with no more than a 33% discharge per night (highly recommended for AGM), that would mean I'd need at least a 72.0 Ah AGM. That could probably be sufficiently charged by a single, 160 Watt panel.
I'm a happy camper now.
05-11-2015, 04:22 PM
(This post was last modified: 05-11-2015, 05:02 PM by OMyMyOHellYes.)
2.0-2.2 amps is WAY overstated. They either have no idea and are just throwing numbers around. Or just outright fibbing. I will guarantee that the draw at 6 cm without heated humidification is going to be under - way under - 1 amp.
And who highly recommends no more than 33% discharge for AGM batteries? Most of the AGM batteries we discuss are deep cycle batts that will happily dip to 70-80% discharge and come right back (12 V batt considered discharged at 10.5 V).
WELCOME! to the forum.!
Much success to you with your CPAP therapy.
(05-11-2015, 05:09 PM)trish6hundred Wrote: Hi Timbo,
WELCOME! to the forum.!
Much success to you with your CPAP therapy.
Thank you! It actually went quite smoothly and took no time at all to adjust. I think that's because I have a fairly minor AHI. Also, I drive commercially, and it's now a yearly requirement that I prove I've been using the machine, so if I want to keep my job, I have to do it. I found that was very good incentive to adjust as quickly as possible.
As for the battery, I think the 33% is if you're planning to recharge it off fairly low Watts of solar only. AGM's require a pretty high initial charge rate like you'd get if you used your alternator or 120 Volt plug-in charger, and that's something you don't get with most non-adjustable charge controllers.
I'm trying to run as few panels on the roof of my tiny van as I can get away with, so it's limiting my "recharging strength". You can charge at lower rates for a while, but over time it's detrimental to battery life to deeply discharge it and then not "hit it" with sufficiently high initial charge rates (%).
I may invest in an adjustable charge controller to alleviate that issue.
05-12-2015, 01:00 PM
(This post was last modified: 05-12-2015, 01:04 PM by Timbo.)
(05-11-2015, 08:23 AM)OMyMyOHellYes Wrote: Are you running it at a strait pressure of 6 cm H2O? If you run it in auto mode, what is your max pressure and 90% pressure? I figured mine at a pressure of 11 (which is usually my 90% pressure - average is around 9) - I did the testing and figured I can safely get more than 5 sleep-nights out of a 35 AH battery with no heated humidifier, just like krelvin said... If you are running a straight 6 cm, you should have no trouble making a week.
Let me know if that doesn't do it for you. If you really really need it, I could set mine up like that and run it for an hour or two while watching TV and let you know what amp draw **I** score. Your number would still likely be different in that you and I probably don't have the same breathing patterns, but I am betting it would be close.
Thanks for those helpful responses! That gives me a good base-line.
Auto min: 6.0
Auto max: 20.0
90% (1 day = 10.0, 7-day = 7.7, 30-day = 7.6)
That sounds pretty close to what you're getting, so I should be able to expect similar results.
I'll probably go a bit larger than 35 Ah, though, because I plan to run other things off the house battery, like LED lights, a 12V fan and maybe a 12V fridge.
(05-11-2015, 04:22 PM)OMyMyOHellYes Wrote: 2.0-2.2 amps is WAY overstated. They either have no idea and are just throwing numbers around. Or just outright fibbing. I will guarantee that the draw at 6 cm without heated humidification is going to be under - way under - 1 amp.
That's also good to know! If I knew that my system was only using 1 Amp, I could get away with a LOT less solar.
05-12-2015, 02:57 PM
(This post was last modified: 05-12-2015, 03:00 PM by OMyMyOHellYes.)
I measured the current draw on my Respironics 560 at my average pressure of 9 cm, no heated humidifier, a couple of months ago for another discussion (that discussion is at the link below) - it drew 0.35 amps. Current draw for a full night would be 2.8 amps. Figuring in a 50% fudge factor (2/3 of the stated battery capacity), the 35 AH battery would reliably get me 8 nights of CPAP power. 12 nights under perfect conditions with a perfect battery which would never happen, thus the 50% fudge factor.
Like I said, this was consumption I measured with me breathing and is more comparable to what ResMed publishes for their S-9 on battery at those pressures - estimated at approx 0.5 amp current draw (per ResMed 0.46 amp @ 8 cm, .55 amp @ 10 cm and splitting the difference between the two), but that is having to use a converter to bump the voltage up from 12 to 24, which would introduce some additional inefficiency that you wouldn't encounter with the Respironics at 12 V).
for the older thread.
That is WAY WAY WAY less than what the customer service rep at PR was throwing at you (I'm guessing he was guessing, not actually looking up real consumption data). I have called and they would absolutely NOT discuss any power consumption data. It was like it was forbidden.