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anne myette 04-26-2016 07:22 PM

C-Pap Machine while boondocking
We are planning a six week trip in our Scamp, our first trip on the road. We have a marine battery on the tongue. We have to run two C-Pap machines at night.
I am sure this question comes up a lot in this group. What do we do on the nights we aren't in a campground.
We bought a 750 amp power station and tried it out at home. It only got one machine half way through the night. So that isn't going to work.
Tomorrow I am going to put a charge on the marine battery to see if that can run them.
I do not understand the workings of the electrical and converting AC/DC stuff. I sure hope we can make this work. Six weeks in campgrounds is out of the question financially.
I am hoping a lot of people out there have already figured it out. Please let me know.

Darwin Maring 04-26-2016 07:40 PM

Will your machine run directly on DC?

KenjiFox 04-26-2016 07:49 PM

By 750 amp power station I assume that's a jumper block, and it said 750 amps on the box. This is typically going to be a high amp discharge 12AH AGM battery. Normally said to have 650 amps of starting power. It could also be up to an 18AH AGM battery inside.

I would not expect that to run a c-pap for very long at all.
You may want to get a kill-a-watt meter and see how much power the machines actually require. From there you can figure what you need in battery capacity.
For lead acid batteries you should not drain them over 50%, so get double the capacity that the math would suggest.

The next part of the battle is making sure that you have a way to charge those batteries back up 100% by the next night.

rainjer 04-26-2016 07:57 PM

There are a lot of factors in you question.

What model CPAP do you have?
Do you use the humidifier?
Can you get a DC plug for your machine?
What are the pressure settings?
How many hours do you sleep?
Does you battery power more than you CPAP?
What size marine battery? (Amp Hours)
Do you have a way of charging the battery during the day?

I have a CPAP I have been using camping for 15 years. This is how I do it.

I have a old Respironics CPAP that I bought a 12V plug for so I can run strait off the battery. I do not use a humidifier (never have even at home). I have 2 Walmart group 27 deep cycle batteries rated at 115 amp hours each. I use one to power the trailer and the other to power my CPAP. the battery to power the trailer is on the tongue. The other is in a portable battery box that has a build in 12V socket that i carry in the back of the truck and then put under the bed when camping. I carry a 15W solar charger to put some charge back in the battery during the day. The trailer has all LED lights.

Last summer I wen on a 10 trip to California and was able to sleep 8 hours a night 9 nights on the portable battery and the trailer batter was still at 90% when I got home.


Doug P. 04-26-2016 08:01 PM

One thing, if your cpap machines are running humidifiers you might want to try them without. This will cut your power draw.

Paul Braun 04-26-2016 08:15 PM

My son uses a CPap machine while traveling with us. Being disabled he comes on almost all our trips. The first thing I did is obtain an inexpensive cord, designed for his CPap, that converts the unit to 12 volt. This cord had a cigarette lighter adapter on the end, There are a variety of machines and you need to find the model with the correct amperage, the safest method is to visit the provider or if you are comfortable search for a source on the internet. If the current power cord for your CPap has a "brick" as part of the cord you have a machine that runs on 12 volts. The brick converts 120 to 12.

So using an inverter to convert 12 volt battery to 120 volt, plugging a power cord into 120 and then reduce it to 12 volt for the CPap machine is probably not the best method. Going directly from you battery to the CPap will give the best performance.

Since we boondock the majority of the time I find that four days is the longest we can run the CPap machine before getting our dual six volt batteries below 50%. Everyone's experience will vary due to the brand of machine, what settings (pressure) you use on the machine and how long you run it overnight.

With two machines you may need dual six volt batteries just to get a complete night of usage. More than one night and you will probably need solar to replenish you usage.

One cavaeat to running machines as recommended above, most machines will turn off the heater on the water supply when running direct 12 volt. For some people this is a deal breaker, they need the heated water. If you have to have heated water in one or more of your CPap machines I fear you may not be able to boondock, those heating elements will just take to much power for a battery (s).

KenjiFox 04-26-2016 11:13 PM

1 Attachment(s)
Given the length of your trip, and how you don't always plan on being at a powered campground....
You may want a small generator. Before anyone starts throwing rocks at me please note that I only mean this for when you are parked AWAY from everyone else. Do NOT run any generator all night near others. No matter how quiet.

That said, this is my all time favorite little generator. It even runs my AC, it's cheap, light, small, pure sine wave so it's safe for computers and electronics, and it seals vapor tight so there is no smell even when you take it indoors.
Oh and I forgot to mention (edit!) It's QUIET! Nearly Honda or Yamaha quiet.
I LOVE this thing.

Here is a picture of mine sitting in my Scamp's sink. It's a small generator that only weighs about 23lbs. Yes, I installed a fairly large sink, but still. :D

If you plan on parking out in the middle of nowhere and boon docking a lot, this might be your best bet. You could then run the water heaters and all on the c-paps and still wake up with fully charged batteries.

IG800w (all models of this are the same thing, different labels slapped on.)


Look for a price of about $250 to $280. It fluctuates.
The Dirty Hand Tools brand just popped up with these. They beat me to importing the 1200w and 2000w versions! I love these so much I intend to brand them and sell them myself. They appear to have the best price on the 3,200 watt version if you need a generator with some major kick to it. It's even got remote keychain electric start.

Steve L. 04-27-2016 05:03 AM

You are right; There have been many discussions about CPAPs on the forum. Persumably you ran a search before you asked and read through the posts.

From a pessimistic perspective, there really hasn't been any recent groundbreaking progress that changes the laws of physics. There may be different machines that use less battery. I would expect that would be an issue for a CPAP forum, if there is one and I have to believe there are. Chargers have been getting smarter and quicker but this doesn't change the fundamental battery drain of the CPAP. Two machines at once seems a little problematic.

The relatively simple calculation of amp draw times hours the machines run will provide an estimate of the battery capacity required. Be sure to factor in inefficiencies of inverters plus something for loss of capacity as a battery ages. It may turn out that you just can't boondock that often (i.e. days in a row) or at all without a couple of batteries and a generator to charge them. Organized campgrounds may be the cost of camping for you.

honda03842 04-27-2016 05:34 AM

Our son runs a CPAP machine.

He has two batteries on his Scamp 13 tongue and is more than adequate. He has a 80 or 100 watt solar panel to recharge during daytime hours. Of course he is not running two. However, bigger batteries are a possibility and probably a necessity.

Owning a small generator would cover weak sun or no sun days for you and in some boondocking locations may be able to be run at night.

Thom Rowland 04-27-2016 08:34 AM


Originally Posted by Paul Braun (Post 584197)
If the current power cord for your CPap has a "brick" as part of the cord you have a machine that runs on 12 volts. The brick converts 120 to 12.

This is not always true. I have a CPAP machine that the power supply (you call it a brick) converts 120 volts AC to 24 volts DC. I had to get a converter to convert 12 volts DC to 24 Volts DC to run my CPAP when not on shore (120 volts AC) power.

War Eagle 04-27-2016 09:08 AM

Anne, The original owners of our EggCamper set it up for touring-style boondocking with two CPAP machines and a crock pot. I'll explain. They mounted three 12V batteries on the tongue (tongue weight about 320 lb) and ran a dedicated pair of tinned marine-grade 8 gauge wires to a 1000W 120V inverter (AimsPower) located over the sink and near the bed. The three 12V batteries and inverter were enough to run both CPAP machines (don't know makes or models) through the night. During the day, they were back on the road travelling, and they used the alternator of the tow vehicle to charge the three camper batteries back up so they wojuld be ready for their next night's stop. As for the crock pot, after stopping for lunch and before hitting the road again, they would load the crock pot with whatever they wanted for supper, place it down inside the sink for stability and plug it into the inverter. When they stopped for the night, they would have a hot crock pot meal ready for them. And that's how they told us they boondocked through British Columbia and Alaska running a crock pot by day and two CPAP machines by night! Dale

Darwin Maring 04-27-2016 09:32 AM

I checked mine this am and it is 24VAC.
I also checked on the Internet and there is a traveling machine that can be purchased. Do some research so you can make a good decision.

anne myette 04-27-2016 10:38 AM

This is the best suggestion yet! I went to Amazon and they are not available at this time but I will search to find it. Thank You!

How lucky someone left all that for you! I love the idea of the crock pot. I need an electrician to help with this now.

anne myette 04-27-2016 10:41 AM

Best suggestion yet! I went on Amazon but they are not available at this time. I will search one out elsewhere. The Honda we looked up was $1000 so this was welcome. Thank You.

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