Cpap on battery power-Real world results.

[Rob K]

The forum and members have helped me a lot. Hopefully I can help and contribute in some way. I've been reading the threads about running cpap on battery and it made me think I should post my results from my last camping trip. I can look up and post the total number of hours and pressures from my trip using the Sleepyhead software. The info should be useful to a number of people when looking to choose a battery size for their machine. Maybe this can be the start of a comprehensive list of real world results.

Equipment:
Machine: Remstar Auto 560P
Humidifier: Yes
Hose: Heated
Mask: Airfit P10
Power adapter: 12vdc cable
Battery: 79Ah Deep Cycle AGM
Battery case: Newport Vessels trolling motor battery case
Charger: Did not charge while camping

Settings:
Pressure range: 10-14cm
90% pressure: Around 11cm most nights
Humidifier: Off
Heated Hose: Off
Ramp: Off
Power: Unplugged machine from battery when not in use to minimize phantom power draw

Results:
Number of nights: 9
Total hours: 62.25
Avg hours per night: 6.92
Battery voltage full charge: 12.8vdc
Battery voltage after use: 12.3vdc
Battery discharged: around 50%
Battery charge time: Did not charge while camping

[CapnLoki]

Thanks for the info. This is consistent with my results. You can find them at the link in my signature, near the bottom of the first page.

Without humidifier, I used 4 Amp-hours a night. At that rate, I would use 36 AH in 9 nights. Your pressure is a bit higher, but you ran only 7 hours a night instead of 8. This works out to about half of your 79 AH battery.

edited to fix typo

[herefishy]

This mystifies me, I wish I had the specs on my RV battery setup, but I know there were 2 of them, and they were always discharged almost completely after one night of running my old respironics cpap. Does this sound crazy"?

[CapnLoki]

This mystifies me, I wish I had the specs on my RV battery setup, but I know there were 2 of them, and they were always discharged almost completely after one night of running my old respironics cpap. Does this sound crazy"?

A modern cpap pump alone should use under 10 amp-hours a night, easily handled by an RV (or boat) battery in good shape. However, if you use the humidifier and heated hose, the usage could be 30 AH or higher. In addition, if you use an inverter, that could double the load (due to inverter inefficiency) and now its possible to seriously deplete a battery.

If you can provide all the details (model, setup, batteries, etc.) we can make an educated guess on what happened.

[KenM]

9 nights on a single charge?
Nice




just googled a battery like that. OUCH, pricey

[CapnLoki]

9 nights on a single charge?
Nice
just googled a battery like that. OUCH, pricey

http://www.amazon.com/75Ah-Battery-Wayn ... B00OZMVI46
$140 doesn't seem like too much for 9 nights, with a 50% reserve. This could possibly go 2 weeks.

If the 50 pound weight is off putting, then 2 35 AH batteries at 24 pounds each might do better.

[Rob K]

A standard deep cycle battery should work just as well.

AGM's aren't cheap. I got a real good deal though on the one I own. I think I payed around $100 or so for the 79ah battery on sale. I've read they may have a longer life expectancy than the standard lead acid so I figured I give one a try. They are supposed to be able to be discharged through many more cycles. Might end up being cheaper in the long run. This battery serves dual purpose for me. Trolling motor battery and cpap. When not in use I've noticed they go a real long time, several months, without having to do a maintenance charge.

[Rob K]

How much do you think the mask plays into all this? I purposely used the smallest mask I owned which is the Airfit P10 nasal pillow. I figured this mask would have the least amount of leaks and require less work from the blower to maintain proper pressure.

[CapnLoki]

A standard deep cycle battery should work just as well.

AGM's aren't cheap. I got a real good deal though on the one I own. I think I payed around $100 or so for the 79ah battery on sale. I've read they may have a longer life expectancy than the standard lead acid so I figured I give one a try. They are supposed to be able to be discharged through many more cycles. Might end up being cheaper in the long run. This battery serves dual purpose for me. Trolling motor battery and cpap. When not in use I've noticed they go a real long time, several months, without having to do a maintenance charge.

The problem is that the alternative to AGM is a traditional flooded battery. Although this can work in a contained area, such as a car starting battery, flooded batteries tend to leak when tipped. They also tend to release gas when charged, and have been known to explode if seriously overcharged. I have used these as my primary boat batteries for many years, and as careful as I try to be, every few years there's an "incident" that ends with cursing and some holes in clothing and sometimes appendages! The "maintenance free" versions are a bit safer, but have limited life. Given that the cost of AGMs has dropped dramatically, almost to the level of a quality flooded battery, I see no reason to keep a bucket of acid in my bedroom or carry it around a campsite. For my backup purposes, a $65 AGM is possibly overkill, so I haven't considered cost effectiveness.

As you note, AGMs have a low "self discharge" so the can go longer without a recharge. Putting it on a trickle charger, such as a BatteryTender, every month or so is enough.

I haven't switched to AGMs for the boat yet because I'm not convinced they are cost effective yet. My "House Bank" cost $700 last time (a year ago) and an AGM equivalent might be $1000; maybe in about 5 years when its time to replace I'll switch over. My starting batteries are AGM because they are tucked away where its difficult to add water, and I want to take advantage of the low self discharge.

[CapnLoki]

How much do you think the mask plays into all this? I purposely used the smallest mask I owned which is the Airfit P10 nasal pillow. I figured this mask would have the least amount of leaks and require less work from the blower to maintain proper pressure.

An interesting question - I use a full face mask which has a substantial vent. I think more than half the pumped air gets vented out without being inhaled. Its conceivable that a different mask saves some of the power. However, I can't imagine using a different mask to save a few bucks on the battery cost.

On the other hand, for the minimalist traveler (or mountain climber) I can see going with the smallest, lightest gear.

[jagzoo]

For those who are interested in a light portable battery setup. My setup in the Phillips Respironics 560 APAP and a PowerAdd 32000amp Lilhium battery. With the APAP set on straight CPAP and a setting of 11, humidifier off, no heat to hose, I can get 3 nights of about 9 hrs each. I then recharge using 110, 12v, or solar - whatever is most available. Actually, I have 2 batteries, so I can go longer. If you think it is important, I usually use either a Dreamweaver or ResMed p10 mask. I’ve been very happy with this set up and plan to keep updating my 560 with my own funds as long as they are available, for this purpose, while using Medicare/insurance for the q5yr updates to newer models, for home.

[herefishy]

n reference to my earlier post about my batteries being discharged after one night on the old respironics cpap, i have 2 Kyocera solar panels(80 & 75 watt), a pair of Concorde AGM 6 volt 220 ah batteries, an Intellipower PD9145A converter along with a Charge Wizard. I have a cigarette lighter outlet so I can plug the cpap directly into the battery system, so am i wrong to expect 10 amps x 9 hours or 90 ah x 2 x 220 or at least 4 nights out of the system?

[tampadan]

I'm sorry I wasn't able to glean an answer off the comments. I get confused by watts/amps/volts.

I am thinking about buying this battery to power my Resmed CPAP while camping. It would likely be at most 3 nights in a stretch between charges. Is this a good battery to buy?

Black & Decker 500 Watt Power Station

It is about $100 at Walmart. I could not post a link per forum rules, but if you search for that on Walmart's web page it will come up with the model I am considering buying.

TIA

[Guest]

I am thinking about buying this battery to power my Resmed CPAP while camping. It would likely be at most 3 nights in a stretch between charges. Is this a good battery to buy?

I couldn't find any specs on the battery but there is an old review on the page, if I have the right one, that claims they got 3 days. Try it at home first.

[CapnLoki]

I am thinking about buying this battery to power my Resmed CPAP while camping. It would likely be at most 3 nights in a stretch between charges. Is this a good battery to buy?
Black & Decker 500 Watt Power Station...

FIrst, the battery - Inside the Power Station is a 18 Amp-hour battery. The rule of thumb is "If you only discharge 50%, you can get hundred's of cycles. If you discharge 75%, much less, maybe well under a 100." Also, a battery will decay over time, so after a few years it could be down to 14AH or less. So depending on how often you use it, how much you rely on it, and how long you expect it to last, you should have a target maximum use of between 9 and 14 Amp-hours. BTW, you can buy a replacement battery for around $40.

So how much do you need? You don't mention your equipment, but we can guess. First of all, the humidifier and heated hose are out of the question - you won't last a night if either are on. If you have one of the common ResMed 9 or 10, or a Respironics 550 or 560 or a Dreamstation, and you use average power, the load is about 5 Amp-hours a night. However, this will require getting the DC adapter for your model. If you use an inverter, you double the load, so its more like 10 Amp-hours a night.

So the net result is that if you run directly on 12V with an adaptor, you might squeak by, using something like 12-15 Amp-hours for three nights. However, if you use the inverter to run on AC power, you probably won't make it through two nights.

On another note, this unit is on Amazon Prime at $97. There are 430 reviews with an average 3.5 stars, but 25% one star. I generally avoid any product with that many bad reviews, and I would especially avoid such products in "mission critical" applications. This is part of the reason I've been somewhat negative on this style of power pack or jump starter.

If you follow the link in my signature you'll find my setup near the bottom of the first page. It uses the same style of battery, but twice as large, plus a high quality battery charger. Some minor assembly is needed, but you can get by with a bit over $100.