CPAP Power Questions

[NMC_EXP]

I need some advice.

My recent tests of camping without using the CPAP have shown doing so is a mistake. I'm dumber than a box of rocks when it comes to electricity so I have some questions regarding using a CPAP while camping without access to 110 VAC power. Simple and inexpensive solutions are good.

Background:
--The CPAP is a ResMed S9. I'd use the pump only, not the humidifier.

--Two types of camping: (1) sleeping in a tent or in an FJ60. The FJ60 has a single battery. (2) A small RV trailer with a single 12VDC battery. I have a solar panel and controller of unknown specs my brother used with his RV.
--Most trips are one or two nights.

Questions:
--Inverter: I see references that an inverter used for a CPAP ought to be a pure sine model. Is this due to "dirty power" damaging the electronics?

--Power source options: I need to buy a jump start power pack anyway. Would powering the CPAP off one of these be an option? How about using a motorcycle battery and recharging it with the solar panel?

--Other?

Thanks

Jim

 

[Airmapper]

Questions:
--Inverter: I see references that an inverter used for a CPAP ought to be a pure sine model. Is this due to "dirty power" damaging the electronics?

--Power source options: I need to buy a jump start power pack anyway. Would powering the CPAP off one of these be an option? How about using a motorcycle battery and recharging it with the solar panel?

I'm not familiar with these machines, so I'm not really sure what the power draw is. Some numbers on that would be useful.

Best I can tell from a brief Google search it has either a 30W or 90W adapter brick, and best I can tell uses DC power anyway. If this is the case, you may be able to eliminate the inverter and convert DC to DC, which will be much more efficient and thus run on a battery longer.

I found this which appears to be the ticket, if that fits your machine, it would allow you to interface with a 12v battery directly: http://www.resmed.com/epn/en/health...ories/s9-dc-dc-converter-24v-90w-output-.html



For the power source, I'd be leery of the lithium pack for a long sustained draw. I attempted to charge a drone battery from mine, which is a similar long term constant draw at significant amps, and despite having a large capacity pack it flattened it in no time. Those seem to excel at delivering large amounts of power in a short time. They are good enough for low draw over longer times, like charging a cell phone or camera.

I think you would be better off with a a small deep cycle battery. I built a small power pack out of a plastic ammo can, which sounds like something that would work well for you if you can get by with a small battery.

If someone just a bit smarter than me can pin down the numbers on it's amp draw and estimated run time, that would help you to choose an adequate battery.

 

[john61ct]

Yes forget anything you can put inyour pocket.

Get a killawatt and get hard numbers on AH per day needed for the gizmo.

Add charging phones, tablet? lights & fan? what else?

Personally if you're strong I'd go right up to a big one and not have to worry.

DIY battery box much better value than these predone all in one's: http://www.cheaprvliving.com/forums/showthread.php?tid=23759

 

[dwh]

http://www.cpaptalk.com/viewtopic/t80150/Measured-CPAP-power-consumption.html

So according to that, average power draw 34w per hour measured over more than 4 hours.

34w ÷ 12v = 2.83a

Just to keep it simple and also build in a fudge factor, let's round up to 3a per hour.

To run it for 8 hours you'll need 24 amp*hours battery capacity minimum. 48ah for two nights. But that will be draining the battery down to dead, which is bad for lead-acid batteries, so you should probably go a bit bigger. Like double.


To provide 24 amps a day of recharge into a battery using solar, you'd need 100w of solar aimed dead-on to the sun for at least 6 hours per day, or more solar if you won't be re-aiming the panel every hour.

 

[Shadow503]

I built my battery system to support my CPAP while camping (Resmed 10 Autoset). I use the Humidifier; dwh's numbers look about spot on from what I've seen. You should be able to find a direct 12V power brick for your CPAP to eliminate the inverter (and make it more efficient). I camp with a 100AH Universal Battery SLA.

 

[RAFoutdoors]

I too use a CPAP. Mine is a Philips. I have a Goal Zero Yeti 400 and can get about 16-18 hours use before having to recharge. I do not use the heated humidifier but just add distilled water to the chamber and it delivers a limited amount of humidity. I can charge it using the 12volt DC cord, solar panel or direct 110V wall charge. This gives me a lot of options.
I agree that going camping without your CPAP is a mistake. I have tried to and lost a lot of sleep. Better sleep-better trip.
Safe travels.

 

[NMC_EXP]

This is a lot of great info - many thanks to all.

Finally found the manual. Looks like this pump is 12 VDC. The factory power pack is apparently a 110 VAC to 12VDC inverter. It also lists an optional Resmed brand battery pack.

I'll dig into factory options some more.

 

[NMC_EXP]

I agree that going camping without your CPAP is a mistake. I have tried to and lost a lot of sleep. Better sleep-better trip.
Safe travels.

The last trip convinced me. Home is about 5,000 ft. We camped at 8,000 for three nights - got very little sleep.

 

[RAFoutdoors]

I think factory options are always better in a piece of gear that is so important for your well being.

 

[NMC_EXP]

I think factory options are always better in a piece of gear that is so important for your well being.

Very true, but the temptation to jerry rig some simple & cheap "solution" is always there.

 

[chet6.7]

[h=1] [/h]I use the biggest AGM from my local auto parts store, O'Reilly's.
I use a different machine, but I have used the battery for 2 nights without recharging.
[h=1]"DC Converter 24V 90W For S9™ Machines"[/h]

https://www.cpap.com/productpage/DC-Converter-For-S9-Machines.html

 

[Mfitz]

http://www.cpaptalk.com/viewtopic/t80150/Measured-CPAP-power-consumption.html

So according to that, average power draw 34w per hour measured over more than 4 hours.

34w ÷ 12v = 2.83a

Just to keep it simple and also build in a fudge factor, let's round up to 3a per hour.

To run it for 8 hours you'll need 24 amp*hours battery capacity minimum. 48ah for two nights. But that will be draining the battery down to dead, which is bad for lead-acid batteries, so you should probably go a bit bigger. Like double.


To provide 24 amps a day of recharge into a battery using solar, you'd need 100w of solar aimed dead-on to the sun for at least 6 hours per day, or more solar if you won't be re-aiming the panel every hour.

I think the OP said they weren't using humidification, and the link posted which indicated 34w was for humidified use. If I have this correct the draw for non-humidified use will be a lot lower, so solar/ battery needs could be a lot lower. Am I mistaken?

 

[landsharkman]

I use the Battery that is made for the cpap and charge that off the yetti or the truck

 

[dwh]

I think the OP said they weren't using humidification, and the link posted which indicated 34w was for humidified use. If I have this correct the draw for non-humidified use will be a lot lower, so solar/ battery needs could be a lot lower. Am I mistaken?

You could be right. I don't use one myself, and couldn't find any power consumption numbers or a user manual with numbers on the product site, so I had to work with what I could find.

The OP said he didn't know anything about electric, so I whipped up a quickie estimate based on the numbers I did find to show him how it's done.

How much less does it consume without the humidifier?...no idea until someone tests it and reports the results.

Until then, I'm comfortable using worst case numbers for an off the cuff estimate.

 

[Rufus]

Absolutely you can. I use a 23 watt high efficienty Solbain panel charging a 32 amp AGM battery which is about 1/2 the size of a car battery. I put the battery on the solar charger (that has a built in regulator) all day and it will bring the battery up to full charge no problem.

Buy the 12 charge cord for your machine and a cigarette lighter adapter with battery clips from the cpap store on line. You'll be set.

I chose not to use a lithum battery due to cost.