Seeking some experienced advice - CPAP users

tonyangie2013

Good evening everyone,

My wife and I are getting into the RV experience a bit late in life but we are looking to purchase a Tab 400, with bunks to take the grandkids.  We've done so much research but would really like to hear from some experienced campers that have been camping and sleeping with CPAPs.  It seems when plugged in at a site, should be no problem at all, but what about if we are traveling and need to stop for a night and need to rough it?  What do y'all do?  Any input would be greatly appreciated.

Thank you and God bless.

Tony and Angie

Bayliss

@tonyangie2013, I use a separate CPAP battery.  It usually lasts two nights.  I carry a 2000W portable generator, so I recharge it while I am charging my trailer battery, such as when boondocking.  When I am at a campground with hookups, I use the AC power there to charge it.  You can also buy a 12-volt adapter with a cigarette type plug-in charger to charge the battery in your tow vehicle while driving.  Regardless, in your situation, the T@B 400 likely will have sufficient 12V battery power, and also an inverter, so if you have sufficient battery storage (amp hours), you can power your CPAP that way.

tonyangie2013

Thank you Bayliss, really appreciate the information!

subkron

My 400 has the AGM batteries and both my wife and I use CPAPs. I purchased DC adapters for them rather than running them on the invertor snce the invertor, though convienient, is not very power efficient. I usually sleep 6hrs my wife longer and my battery goes down to about 83%.  In addition to the roof solar I also have a 100W solar suitcase to help get the batteries charged after the nightly drop.  We have gotten them down to the low 70% if I had a cloudy day where I could not recover the charge. We have Resmed Airsense 10 & 11 models.
I do unplug the CPAPs as soon as we wake up because even just stitting there they pull a few watts. So all in all it works but TBH once these AGMs die off it will be nice to convert to Lithium.

FishDoctor

I have been using my CPAP in my T@B 320S for many years. You are correct that it is not an issue when on shore power -- just use the normal AC adapter you would use at home.

When boondocking, I use a DC-to-DC Converter that is designed for my ResMed machine. On one end, the adapter plugs into a 12-V (cigarette lighter) plug  and the other end has the proper power plug to match my CPAP machine. When using this adapter, you are running off the T@B's 12-volt battery. This is considerably more efficient than using an inverter that would plug into the 12-V plug and then allow you to use your normal (shore-power) power supply for your CPAP. The DC-DC Converter looks like this:

The suitability of this arrangement requires you to think about how many nights you need to have battery power for your CPAP before you can recharge the battery and how much power your CPAP uses. The amount of power you need will vary depending on the make and model of your CPAP machine, the treatment pressure you need, and the comfort features you have enabled (e.g., heated hose temperature, humidifier setting). I generally turn off the humidifier and hose heater when boondocking to reduce the power requirement. For me, that comes to a current-draw of about 1.2 amps which requires about 15 Amp-hours for an 8 hour period. So, if boondocking for 3 days, I would need to dedicate about 45 Amp-Hours of my battery supply to my CPAP. I decided to install a separate 100AH Lithium Iron Phosphate (LiFePO4) battery and a 12-V outlet that I primarily dedicate to my CPAP (plus charging my cell phone or other USB devices when needed). Also, you need to make sure you unplug your CPAP from the power supply when not being used -- there will likely be some power draw whenever it is plugged in. In practice, I can get 5 or 6 nights of good sleep from my arrangement without recharging. 

If you want to get a more detailed guide to using a battery for your CPAP, here is a link to a RESMED document: https://document.resmed.com/documents/products/serviceandsupport/battery-guide/battery-guide_glo_eng.pdf that explains things and provides estimated power needs for RESMED machines (note, I think this document is from 2018, so it might not have the information for your machine if you have a recent model). Maybe you can find something similar if you use a different brand/model.

So, here is what I would recommend:

1) Determine how much additional battery power you need for your CPAP and compare that to your existing battery power setup. This is in addition to your normal battery useage. From your post, it sounds like you and your partner are both using CPAP machines. If so, remember to double that estimate. This will help you figure out whether you have enough battery supply or if you need to add to it.

2) Obtain the proper DC-DC converter for your CPAP model(s). Make sure that it has a power plug that is right for your machine. Also think about the length of the converter's power cord and make sure it will reach from your DC Outlet to your CPAP while you are sleeping.

3) Test your setup before you are stuck away from shore power to estimate what your ACTUAL power draw looks like. A shunt on the battery being used is your friend here because you can actually monitor how much power (amp-hours) are needed during real-world overnight usage. The shunt I use has a bluetooth module that allows me to track battery usage on my cell phone. I generally check that before going to sleep and again when I wake up so I know what the battery's state-of-charge looks like.

4) Remember to turn off (or turn down) the heater hose temp and turn off the humidifier if you can -- those greatly increase the power draw. You could also test different setups and use your battery shunt data to inform you how much of a difference that makes.

tonyangie2013

We appreciate this amazing community and the information and help provided. Thank you to all.

Homebodyatheart

When dry camping I have used a 12v adapter, which works well and doesn’t drain the battery. I also travel with an EcoFlow power bank. I can easily get three full nights of sleep with this and have a bit of power left over. I can also
run my electric kettle for coffee, which uses very little power. Enjoy your journey!