Jumpstarter to power CPAP for camping – problems

[Handgunner45]

Unplug humidifier and use Remstar only at 1-amp-hour with humidifier kinder like passover it will last more then enough!!!!

Rich03079

_________________

Humidifier will not run on 12vdc.

If you were pulling right at the 2 amp rating of the fuse it would take a period of time for it to actually blow. It requires a much larger overcurrent condition to blow the fuse right away.

[Rich03079]

I did email Tech-help online with Remstart on the Auto M-sereis
AC is uses less amp/hours then DC which is higher!!!!

Machine only draws 1-amp/hour without humidifier on AC

The humidifier adds 1.7 amp/hour load to demand on AC

so 1amp/hour machine and 2.7 amp/hour using humidifier

I use Black & Decker Electromate 400 which is $87 plus shipping

http://www.tylertool.com/blackanddecker44.html

[billbolton]

RemStar auto needs 1-amp-hour on CPAP machine AC, and the humidifier needs 1.7 amp-hours, so combined 2.7-3 amp-hours on AC.

AH is not a useful/meaningful measure for AC power. Presuming the current ratings above are for a 120V AC supply, a 1 Amp current draw is 120W of energy consumption (1A * 120V = 120W)

An energy drain of 120W at a supply voltage of 12V would inidcate a equivalent 10 Amp current draw (10A * 12V = 120W). Even allowing for inefficency in the internal switch mode power supply in the flow generator that seems a very unlikely DC energy consumption figure for just a flow generator.

Cheers,

Bill

[billbolton]

And here is a post where a Remstar user (UKnowWhatInSeattle) claims to get 3 nights with a 22Ahr jumpstarter:

viewtopic.php?t=289&highlight=remstar+jumpstarter

That same thread contains this quote....

The Remstar pro consumes maximum 36W per hour at 12VDC with a pressure of maximum 16 cm. This is without other attachments.

36W at 12V indicates a 3 Amp current draw! (36W/12V = 3A).

What specific Respironics flow generator model are you using Jeff?

Cheers,

Bill

[Guest]

Not engineer, but Remstar email tech told me 1amp for machine only, and add 1.7 amps if using humidifier. 1amp +1.7amp+2.7 amp total I in error may had still been using amp/hour wordage, because using Electromate 400 which is battery & invertor combined. I was using AC power here, and not DC which has higher drain requirements???? Per Remstar techies by email.

Rich03079

[Denverdad]

Bill, it is a REMstar Auto w C-flex. I am not sure if that is specific enough, but it is one of the earlier Remstar units if that helps.

So I made some current draw measurements this weekend! The first thing I should note is that measuring DC current with a meter is a little tricky - at least for this unit - because the current varies a lot. It goes up and down with each inhalation/exhalation cycle, and depends on how deeply one is breathing, and undoubtedly on pressure, c-flex setting, etc. If there was a way to integrate for a period of time and get an average reading with the meter I used, that would have been ideal, but I didn't see how. Anyway, after sitting there with the mask on and the unit running for a while, trying to relax and breathe normally, here's what I found:

My best estimate is that on average my CPAP is pulling about 0.8 amps DC. Instantaneous readings are often well below this, but I also occasionally see values as high as 1.8 amps (but again, only momentarily). While it is hard to zero in an a meaningful average value, I feel fairly comfortable saying that during my test the average DC current was no more than about 1 amp.

Incidentally, I am reading the other thread here which may provide some more data points for this discussion:

viewtopic.php?t=24359&highlight=battery+current+draw

Jeff

[Goofproof]

You are going to have to buy another basket, you are confusing your apples and oranges. The rules of D/C and A/C are different and then just to make it more fun the current draw isn't study. Then there's the loss of energy converting D/C to A/C.

Plug it in and sleep with it, wake up when you start to turn blue. Jim

[Handgunner45]

Are you taking the current readings with an analog meter or a digital meter. Often the current can change to rapidly for the digital meter to respond and thus you will not read the actual maximum or minimum current draw. I would suggest that you just turn the machine on without the mask attached. Take a reading with the hose open to atmosphere and another with your hand blocking the hose. These should be two static readings.

[billbolton]

The first thing I should note is that measuring DC current with a meter is a little tricky - at least for this unit - because the current varies a lot. It goes up and down with each inhalation/exhalation cycle, and depends on how deeply one is breathing, and undoubtedly on pressure, c-flex setting, etc. If there was a way to integrate for a period of time and get an average reading with the meter I used, that would have been ideal, but I didn't see how.

For the purpose of the excercise, note the higher current reading (when you inhale) and the lower current reading (when you exhale) and just average them. This will be close enough for getting well into the ball park in terms of your typical energy usage.

My best estimate is that on average my CPAP is pulling about 0.8 amps DC. Instantaneous readings are often well below this, but I also occasionally see values as high as 1.8 amps (but again, only momentarily). While it is hard to zero in an a meaningful average value, I feel fairly comfortable saying that during my test the average DC current was no more than about 1 amp.

Intuitively that sounds like the sort of current ldraw I'd expect at 12V DC from a contemporary DC powered flow generator. The higher values may be what caused the Radio Shack DC adapter fuse to give out after a while.

Anyway, you still have something of a mystery as to why your battery is not sustaining a couple of nights operation, unless the Jump pack is faulty in some way!

Cheers,

Bill

[Guest]

I guess I sort of let this thread tail off... But thanks for the input everyone. In the end my best conclusion has been that the jumpstarter has some "issues". I may return it, or just keep it as a jumpstarter (it works fine for that).

When I finally went on my trip last week I brought the jumpstarter and the camping gear with the hope of camping maybe one or two days during that time. However I discoverd something I hadn't anticipated: It's d**n cold at night in the mountains of Colorado! So I ended up spending every night at hotels instead (I know, I'm such a wimp!).

But in the spring if I get serious about it again, I think I will look into the deep-cycle battery route.

Thanks again for all the help.

Jeff

[Guest]

However I discoverd something I hadn't anticipated: It's d**n cold at night in the mountains of Colorado!

LOL I knew that!!!! Hey it's cold in the summer, in the mountains, eh!

[Huntsman]

If you aren;t camping extremely far from the car/truck you could get a dual battery set-up on the car. Yeah it's 40lbs to lug to the tent each night, but you will get anywhere from 80-400ah. Several days at least running off a good inverter. When done it just goes back in the trunk and connects back to the charge system with quick disconnects and will be fully charged again within a few hours driving.

I did this for a long time at hunting camp and works like a champ! Could run a low wattage light and even a small tv or radio(or a microwave) for a long time before needing to put it back in the truck and recharge it.

[ColoZZZ]

Forget about the "heated" part of the HH when camping unless you use the humidifier in passover mode (I run the hose the length of my sleeping bag).

I've found that for my M-series Auto a 35 Ah Sealed Lead Acid battery (SLAB) works well for a couple of long nights sleep with even with a nap or two thrown in. I've probably got about 20 nights campig out since last spring using a 18 Ah SLAB for single night trips.

Battery:
12V, 35 Ah SLAB (23 lbs) from Gruber (If anyone's seen a better deal, please post it): http://www.gruberpower.com/gruberpower/ ... efault.asp

Wiring and clips from Radio Shack ("N" size plug for M-series, take in your AC power supply and have the techie make sure the plug's size & polarity and is set correctly so you don't fry your CPAP).

What you see here is about all I know much about electricity. My rule of thumb assumes a very conservative power use rate of 2 Amps for 9 hours for the M-Series, which likely draws less than 1 Amp at 10 cm. I like the conservatism with it to take into account for use in subfreezing nights and also to avoid completely draining the battey. Total cost for a 35Ah heavy-duty setup should easily be <$100.

Good luck getting set up for camping next season!

-Andy

[OldMart]

I just got a Portable Power Pack with a 12V 35Ah Deep Cycle AGM Battery installed. Hope it runs my S9 for a couple of nights. I have a two night camping trip coming up at the end of the month. About 100 of us Hammock Campers are meeting up in PA for a "Hang In." Think I'll test out the power rig at home first. I was able to keep the S9 going for one night on my old 14.8V/6.6AH LiOn battery pack, so I'm thinking the Power Pack will do the job.

[idamtnboy]

I just got a Portable Power Pack with a 12V 35Ah Deep Cycle AGM Battery installed. Hope it runs my S9 for a couple of nights. I have a two night camping trip coming up at the end of the month. About 100 of us Hammock Campers are meeting up in PA for a "Hang In." Think I'll test out the power rig at home first. I was able to keep the S9 going for one night on my old 14.8V/6.6AH LiOn battery pack, so I'm thinking the Power Pack will do the job.

With humidifier off you should. With humidifier on, no more than one night.

Suggestion, next time you have a question such as this please start a new topic. Resurrecting an old topic, especially one as old as this, causes confusion as some members, particularly newer ones, often respond to an earlier post without realizing how old the topic is. Such responses are usually a waste of time and effort as the earlier poster likely is not active on the board.