Using a CPAP in a 32SA while boondocking

[mikervet]

I have a 2022 Tiffin 32SA with 2- 6 volt batteries and a gas/electric fridge and 1200 watt inverter. I would like to use my CPAP machine while boondocking. My CPAP power consumption is 53 to 104 watts. Is there enough power to do this? Where do you plug in the bedroom? I think the only outlet connected to the inverter in the bedroom is the TV. In most cases I would expect to be able to run my generator in the day to charge my batteries. Since CPAP's are so common I would think there are many campers using them. Thanks in advance for any guidance.

[hamm2018]

Originally Posted by mikervet

I have a 2022 Tiffin 32SA with 2- 6 volt batteries and a gas/electric fridge and 1200 watt inverter. I would like to use my CPAP machine while boondocking. My CPAP power consumption is 53 to 104 watts. Is there enough power to do this? Where do you plug in the bedroom? I think the only outlet connected to the inverter in the bedroom is the TV. In most cases I would expect to be able to run my generator in the day to charge my batteries. Since CPAP's are so common I would think there are many campers using them. Thanks in advance for any guidance.

May be easier to install an outlet dedicated to the CPAP from the inverter.

[oldeguy]

my house batteries are 4 six volt and i use a CPAP unit on inverter along with all other 12volt power stuff. Just a note...i've got twice the battery power...fyi

[Crasher]

My guess is that your two batteries should run through the night without issues. If it's cold and the furnace fan needs to run often, it might close, but if you have auto gen start, no need to worry. If not, add auto-start to your generator control. Or, if you find it to be a problem, just add two more 6 volt batteries to double your reserve. My wife and I both use a CPAP with all electric appliances, but we also have 900 amps of battery reserve. If needed, add a dedicated outlet to the invertor as was mentioned.

[dssl]

Your inverter is probably a modified sine wave inverter. It's probably okay on your CPAP machine but a chance it could destroy it.

By the numbers with only 2 batteries assuming they are fully charged you likely have about 220 ah,but it's best to not go bellow 50%. Let's say you have 120ah of usable power in your batteries. 120×12= 1440 wh. If you assume only 10% loss which may be optimistic that gets you down to 1296 wh. I'm not sure how much power your refrigerator and other devices use, but if it's say 300 watt hours for the night, that would leave you with 1000 watt hours for your CPAP, so if for example you wanted to run it for 10 hours you would be able to average 1000/10= 100 watts which sounds like it may work, but it's close, depending on all of the actual numbers.

A 12v CPAP would likely be more efficient.

[twinboat]

Don't worry about the 50% battery discharge myth, if you want to breath at night, you can safely go down to 90% discharge . Just get them charged in the AM.

It will cut the battery life in half, but you will live to change them.

2 batteries are about $300 to replace. Thats not bad every 2 to 3 years or so, with deep discharges.

This is from Lifeline but matchs most deep cycle batteries.

[High Road Travelers]

Originally Posted by mikervet

I have a 2022 Tiffin 32SA with 2- 6 volt batteries and a gas/electric fridge and 1200 watt inverter. I would like to use my CPAP machine while boondocking. My CPAP power consumption is 53 to 104 watts. Is there enough power to do this? Where do you plug in the bedroom? I think the only outlet connected to the inverter in the bedroom is the TV. In most cases I would expect to be able to run my generator in the day to charge my batteries. Since CPAP's are so common I would think there are many campers using them. Thanks in advance for any guidance.

I have a 2018 32SA, but we have the residential fridge and 4 - 6 volt batteries. However our inverter seems to be the same as yours, it's a 1,200 watt modified sine inverter. My inverter outlets are listed below:

1) Refrigerator – Plugged in it’s own circuit in an outlet accessible from the outside panel, and is on a single plug outlet.
2) All Televisions and Entertainment Equipment behind the bedroom TV
3) Electrical Outlet in front of the Passenger seat, near the floor
4) Electrical Outlet under the kitchen sink, up high on the wall next to the stove top. The Outdoor TV is plugged into one of the plugs.
5) Electrical Outlets under the TV in the Living Room, behind the wooden grill panel above the Fireplace
6) Electrical Outlet in Bedroom, on wall of closet over the “dresser” counter top which is below the TV.

Since mine has the residential fridge your inverted outlets may be different, but you may check the one under the bedroom TV on the outside wall of the closet. Your layout may be different, but this plug is next to the HDMI splitter which is in my closet.

Hope this helps some in finding an inverter outlet. Thanks,

[dssl]

Originally Posted by twinboat

Don't worry about the 50% battery discharge myth, if you want to breath at night, you can safely go down to 90% discharge . Just get them charged in the AM.

It will cut the battery life in half, but you will live to change them.

2 batteries are about $300 to replace. Thats not bad every 2 to 3 years or so, with deep discharges.

This is from Lifeline but matchs most deep cycle batteries.

Attachment 357698

My calculations had the SOC going bellow 50%. You can certainly go bellow what I showed, but if you go anywhere close to 10% it's unlikely you will be able to start the generator without using the aux start.

Besides not discharging your batteries bellow 50% another factor that can shorten the life is not bringing them up to full charge fairly often. Unfortunately because of the lead acid charge profile the last 20% of the charging needs to be done slowly resulting in longer generator run times.

I think the bottom line is the OP needs to experiment to understand what his system and usage can support.

[MarkMaxPayne]

Do you actually need your humidifier on your CPAP? That is the biggest draw of power/current as it acts like a hotplate, heating the water reservoir to cause the water to evaporate and the mist to travel through the hose to your mask. Simply turning that off would change your power consumption numbers by perhaps 2 to 3x perhaps?

I was a road warrior in a previous job and picked up a travel CPAP (I picked up the Z1). I ordered mine with a shell and a rechargeable battery that would last the entire night. I also bought a second rechargeable battery as a spare (rarely used in practice, but nice peace of mind). I also found with the battery shell it was great during power outages as it just automatically switches over. I liked it so much it replaced my home machine. I haven't used humidity for well over a decade now with my travel machine being my fulltime CPAP device. The current model is the Z2: https://www.cpap.com/productpage/z2-...l-cpap-machine

Best,
-Mark

[mikervet]

Thank you for the info. I will have to try a few things and see how it works out.

[Mark_K5LXP]

To the OP, you've run into what would be called "system level considerations" which you normally don't have to consider when plugged into mains power. Not that any of this is particularly difficult to understand or manage, just that you have to do it. Can your generator start with 10% charge? Might be a good idea to test it and see. Part of this exercise is acknowledging you will have some compromises to achieve the desired goal. That might mean replacing your batteries every 3 years instead of 5 years, adding batteries or following a prescribed use and charge regimen. None of this is "bad", it just is and it's part of getting to the finish line of being able to use what you have for what you want to do. The rest is details. If getting out in my RV meant I ran my batteries into the ground then that's OK, like the doritos ad, "they'll make more".

Mark B.
Albuquerque, NM

[glenthompson]

Check the power input on your CPAP. Mine uses a power brick to provide 12v DC to the machine. You could fabricate a cable to run directly off the batteries. On our Phaeton the outlets by the bed are on the inverter.

[allegro1x]

Check out Jackery 290 battery generator that's available at Harbor Freight. Can be used inside and can be recharge from household current or solar panels.

[Nanci]

This is how my husband does it when we boondock. Cpap rechargeable battery pack. Just turn the humidity off. https://www.rvtravel.com/cpap986/