CPAP and battery....

I've become a CPAP user and am wondering what folks have come up with to power it? I've done a bit of research, so I know it's not as simple as just buying any battery, as cpap units have peculiar needs, especially if they have a humidifier connected, which mine does (though I can leave the humidifier behind).

Obviously battery power isn't an issue when connected to shore power (though I do wish there was an AC outlet near the head of the bed so I could tuck the cpap into the cabinet at the head). But when boondocking, what battery do you use, and why, and is it working for you?

1-day batteries are easy. It's when you want 3, 4, 5 days that it gets complicated, heavy, expensive....

-Al

 

Al, I just posted setting up an external battery good for 100hrs.
It's easy, A-hem... with the right parts
but basically install an ON/OFF switch on the internal battery wall and then plug in the external (presumably on the ground under the trailer)battery into the cigarette lighter... some 28amps for 100-hrs... should do it.. smaller battery of course, less time etc..
Would that work??? I'm in the middle of doing it now, Sarah/Mick will have How2 I believe on their set up...
Not sure if that was what you're looking for???

Hope that helps..

 

So if you have the CI installed off/on switch, you should be able to do this already?
I think I need to go read Frank's battery thread more closely.

 

Some suggestions, don’t bother with the humidifier, it will drain the battery more quickly than just the CPAP. The benefits of the humidifier are nice but not critical, unlike the CPAP. About the AC outlet, an extension cord under the mattress is an easy solution. For batteries, you will not get a lot of days off your main battery particularly if you have a refrigerator and are using it for anything else. I use something like this CPAP battery option . It is small and stores nicely in the storage area at the front of the bed. I just snake the wires out. I can get three nights from it; your mileage will vary depending on your settings. If I need to go four days or more, I will use the main battery, but I have to exercise good power management to ensure that I keep a reserve. I have a solar panel and can usually top off the main battery if needed. The refrigerator has its own battery. You will need an adapter that works with your CPAP and DC.. None of this is cheap. Look at the battery options at cpap.com, there is are links to manufacturer’s ratings on how many hours you can expect to get based on different parameters. It is interesting reading.

 

Joan,
Yes, if you have the ON/OFF switch aready installed, newer (than mine) do.
I would certainly double check with CI JUST to be SURE, but with the switch installed, you get the battery, attach the cigarette plug to that and then just Turn OFF the switch to your internal one and plug in the external one.
Voila'

Or so I'm believing... it's like a generator, only quiet like.. same idea, just have to turn OFF the internal Battery is the catch and in my case the hard part...

Have part coming tomorrow with a cable so should be good to go then.. heheh... Yah, sure I say to myself... LOL..

 

Thanks Frank. I have the solar package so I will invest in that first. I am interested in knowing what all the options are. A gas generator would be my last choice.

 

thanks for the comments

Yes, it looks like using the humidifier would make it pretty tough

We're going to be off the grid for at least 7 nights, so.....

but we will have a 120 KWH solar panel kit with us, which will help....(and we do have the SUV, of course)

 

ouch

http://www.cpap.com/productpage/resmed-power-station-battery-kit-s9-cpap-machines.html

 

I put my cpap in the cabinet at the foot of the bed and plug it in near the a/c.

 

AlCat

I have an S9 as well, the $700 ResMed solution IRC is basically a one-nighter solution that was designed more for use while in an aircraft than for camping. It is a lithium battery that is very small and lightweight. The $300 Repironics Battery Pack works with any CPAP and is good for 3 days. Remember when reading the tables and doing calculations that you don’t want to run down a battery by more than 50%. I believe that the power-use tables factor this in. They are also conservative. The Respironics battery will shut down before you can damage your battery as will most of the CPAP dedicated batteries. Fwiw, running out of battery while using a CPAP may sound dangerous, but it really isn’t. Your subconscious can easily deal with such a situation.

 

I just posted Mick's write up. It might work for your CPAP machines.

http://www.campinnforum.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=19543#Post19543

 

I am inclined to invest in a solution that I could take on a plane, as I do travel for work.

Now my question is, how do I charge a LiIon battery when camping, using solar? I'll have a 120KWH panel kit with me, and the sun in southern Utah should be regular and strong, so I should be able to "stay ahead" of the draw down.

If I plug my solar panels into the TD, can I recharge the LithIon battery by simply plugging it in to the TD?

Or is this more complicated due to the LiIon battery being different than the onboard TD battery?

If this IS an issue, do I avoid it by only charging the LiIon battery after I throw the TD battery disconnect to "off"?

[This CPAP thing is brand new issue for me, and batteries/electrical is not my strong suit....as you have probably noticed.]

-Al

 

I suppose this begs the question, if I have solar panels, why not simply rely on the panels to charge the existing onboard TD battery, and take my time buying the cpap battery?....

I guess I can't RELY on the solar. If we get a couple days of clouds, having my fridge down is one thing, but having the CPAP down would be another.

 

AlCat,

I think you can get to where you want to be, but you have to remember there is no simple solution short of getting a generator. Without a generator it is all a matter of power management, which will require that you be aware of what capacity you have and what draws how much. You also need to be aware of what power constraints you are subject to. If you are relying on solar keep in mind that you may not always be able to or want to deploy your panel. You will also need a fairly large panel, the more watts the bigger they are. Logistically, running around with a big panel can be a headache. If you are going to depend on your onboard battery you need to track everything else that you are using that is drawing from it. The fan, the water pump, lights and the TV/Stereo all can draw down your battery quickly. Especially the fan if you use it through the night. If you have a DC refrigerator and a CPAP, it will be difficult to run everything off of the main battery, even with solar. Also, everything takes time to charge, depending on your camping style, you need to factor in enough time to charge batteries, either through AC, TV or solar. The lithium-ion battery from ResMed is a marvel, but it is only good for around 13 hours and it expects to have an AC source for recharging. So this means we are back to the efficiency issues of an inverter or we find a DC inverter that might work more efficiently if you want to recharge the lithium-ion battery using solar.

My recommendation is that unless you expect to be doing a lot of dry camping in the near future for four or more days that you do not invest in anything until you feel you are comfortable you understand what the power cost of everything you might be using is. Monitor your battery’s voltage and make sure it does not fall below 11.9 volts, certainly not below 11.58; figures based on a table I use. If you don’t want to manage your power, which can be a real pain, than you might be a good candidate for either Mick’s patented built in battery bank, Mick’s patented external battery solution or a generator. It is still a management issue but at least you will start with a lot bigger source of potential power.

 

well, my solar panels are 120 KWH....

I realize it's complicated...and that it's beyond my knowledge base....but I've got 7 days of dry camping with very little driving coming up...April 20

but at least it's southern utah, so I have a fighting chance

no fan
no stereo
fridge set to 4 degrees C

that's no fun

I need to determine if I can charge the LiIon battery from the TED, from the solar panels...

 

Here is a LiOn battery that can charge from DC

http://www.respiratorysolutions.biz/C-100-Super-Power-Battery-Pack-Single-p/bps-c-100.htm

 

You should be able to do 7 days. Remember you can always charge from the TV. Just don't run out of gas. A 120 watt panel will help a lot. My panel seems to work best when it is overcast for some reason. I think the big question is whether or not you will be able to charge the lithium-ion battery directly from the solar panel; I believe an inverter can be connected directly to a solar panel and that should work for your upcoming trip. There are solar-inverters and methods for charging a battery from a DC source; however, I am not very familiar with them. Something that might help is to purchase an external AGM battery in order to provide you with a bit more capacity. I keep a 55 ah battery and use that for my refrigerator, I charge that battery directly with the solar panel. The solution may not be elegant, but it does provide a lot of flexibility. Another thing to consider is that you don’t need the CPAP for the entire night. The last two hours of sleep don’t get much benefit from the CPAP therapy. When camping, I usually take off my mask after six hours. The ion battery you provided a link to looks interesting, especially the quoted run time of 25 to 30 hours, seems like too good a deal. In any event, it looks like you would still need to get a DC convert to charge from a DC source.

 

Hi, with the NON-ResMed LiIon battery, I can recharge from the TD battery. But I am not sure if I can have the LiIon battery and the TD's AGM battery connected to the solar panel at the same time (i.e., solar input to TD; TD's AGM battery connected through TD to solar; LiIon battery also connected to TD via cig lighter adapter).

Good points re not using the CPAP after 6 hours. (I do not plan to use the humidifier, on the trip)

re the extra AGM battery, would you use that to charge the LiIon when the LiIon gets low? (rather than recharge the LiIon via the solar as I outline in this email?)

The problem with charging with the TV is that we are doing almost no driving once we get to Zion. Maybe we'll have one two-hour drive. When we move, it's about a 40-minute drive to the next spot. (but I do realize that we can charge while parked. I was just pointing out the drive times.)

 

You will only need to top off the batteries so you maybe able charge them sequentially or more likely charge the AGM one day and the ion the following day. The AGM battery gives you a lot of options. For starters, you gain a lot of stored amp hours up front as well as a place to store future amp hours. If you don’t need dc power, you leave it home which saves on weight. I have two 55 ah batteries and I take none, one or both depending on expected need. You can charge the AGM using the solar panel and it helps that you are able to move the panel and battery to where the sun is shining if you are camping in shade. I hook my refrigerator up to it and I believe if you turn off the trailer battery you can plug it into any of the trailer’s dc jacks and use it as the primary battery. I also have an inverter that I attach to it when I need to have AC power, got to grind my coffee beans every morning. The only problem with an external AGM battery is that it is hard to charge them without using AC or a solar panel. Getting them to charge through your car will likely require some rewiring of your car and maybe a dc converter. Maybe another project for Mick.

Your car does not take much gas to idle; I have a 7-pin extension cord so I don’t actually have to hitch up in order to charge the trailer battery with the car. You should be able to get a pretty good charge in an hour. The extra length from the extension cord is not the most efficient way to go but it works.

The two icon batteries you have mentioned seem to have different expectations on how they can be charged. The ResMed Power Station II looks like it expects you to use the normal S9 power block that comes with the S9. I am not sure how to do a solar charge except by using an inverter. The other one looks like you should be able to find a dc converter for it; however, the site does not offer one. The inverter will take longer to charge through a panel than the one using a dc converter, however, I think you maybe looking a difference of about an hour. The AGM batter can charge the ion batter, the solar panel and the AGM battery are just dc sources, albeit, one has storage and the other does not. The AGM batter would have the same issues as the solar pane.

 

After talking with someone at batterypowersolutions.net (Steve -877-445-5228), he is confident I can charge their battery direct from a solar panel that has a controller on it (using cig plug) OR I could plug the battery in to the TD (or the TV) and charge from the TD battery (AGM UPS) or if the solar panel is also plugged in to and charging the TD at the same time. If the battery is plugged in to a DC source, it needs an inverter between it and the DC source.

This is the company making the C100, which I linked, above. (You can use that C100 battery to run other electronics, such as your ipod, etc.)