How to power a cpap

[CactusBob]

I am thinking of using lifepo4 batteries to build the battery bank for the cpap. It is more expensive but it saves a whole lot of weight I don't feel like lugging around. The AGM's I have seen weigh about 24lbs for 35AH battery. Plus its much easier to find an inexpensive case to build with 18650's than an AGM.
If building a 12v system is it better to build it as a 3s or 4s, or is it better to build a 24v system and use a dc to dc converter to drop it to 12v.

Thanks
Bob

 

[snoobler]

4S for LFP.

Efficiency losses in 24V-12V conversion would outweigh any benefits.

 

[MrNatural22]

I am thinking of using lifepo4 batteries to build the battery bank for the cpap. It is more expensive but it saves a whole lot of weight I don't feel like lugging around. The AGM's I have seen weigh about 24lbs for 35AH battery. Plus its much easier to find an inexpensive case to build with 18650's than an AGM.
If building a 12v system is it better to build it as a 3s or 4s, or is it better to build a 24v system and use a dc to dc converter to drop it to 12v.

Thanks
Bob

I went this simple route on a portable power box with a drop in 55ah LiFePo The box has 4gcables inside to connect your battery. It has two lighter receptacles that share a 10a circuit breaker. A simple led power meter. With the main terminals having a 60a circuit breaker. Folding handle on top. I use it mainly for a 45lb thrust trolling motor but always take it camping or in the van for many other uses.
This would be a great box for a 4 cell diy LiFePo pack and BMS. Sized for a group 27 flooded/AGM battery.
Mine weighs about 23lbs with the LiFePo so it’s very easy to carry.

 

[wmills_92105]

I was finally able to test mine last night, it is a Phillips Respironics System One Series 60,
pressure 10.
peak 80w
low 1.3w
both with the heater on.
This was over 13.5 hrs with a total of 285w. Unfortunately my power meter doesn't break it down by night

I really like these smart plugs by Emporia for doing energy tracking. History display in the mobile app by your choice of month/day/hour/minute/second. There are 1 packs and 4 packs.

Amazon.com

 

[HaldorEE]

I was finally able to test mine last night, it is a Phillips Respironics System One Series 60,
pressure 10.
peak 80w
low 1.3w
both with the heater on.
This was over 13.5 hrs with a total of 285w. Unfortunately my power meter doesn't break it down by night

I best 90% of that is the heater. My System one without the heater lasts 14 hours on a 6.6AH battery. That works out to an average power draw of about 6W.

 

[MrNatural22]

Thanks @HaldorEE

I just ordered the 12v dc to dc cord for my respironics dream station $29 from cpapXchange so I can get a base for what my bipap uses overnight with and without the humidifier running.
I have never run it on battery yet and using the inverter seems like a big waste of power.

 

[HaldorEE]

Thanks @HaldorEE

I just ordered the 12v dc to dc cord for my respironics dream station $29 from cpapXchange so I can get a base for what my bipap uses overnight with and without the humidifier running.
I have never run it on battery yet and using the inverter seems like a big waste of power.

Plus it is a lot easier to just plug into a small 12V battery for power outages, camping etc.

 

[UncleTodo]

Thanks @HaldorEE

I just ordered the 12v dc to dc cord for my respironics dream station $29 from cpapXchange so I can get a base for what my bipap uses overnight with and without the humidifier running.
I have never run it on battery yet and using the inverter seems like a big waste of power.

Interesting, I'm looking forward to the results. While I have a ResMed unit, my sister has a DreamStation she never uses and even said I could have before I got mine through health care.
Oh yeah, so I'd like to see about a head to head on 12v consumption.

 

[CJMainer]

you can buy small solar generators off amazon. I have a 300w pure sine portable gen. Its not big but it runs my cpap for 2 or 3 days without charge. Although I purchase a 100 watt renogy mono and it charges the gen up fairly well so I dont need to worry about it. I go camping quite often and never worry about my cpap. also can use a 6v lawn mower battery with a small inverter. https://www.amazon.com/Goal-Zero-Portable-Generator-Alternative/dp/B00D5RVMAM/ref=sr_1_13_sspa?crid=37Z4L9PKQPXRH&dchild=1&keywords=portable+power+station&qid=1608335700&s=lawn-garden&sprefix=portable+,lawngarden,197&sr=1-13-spons&psc=1&smid=AZ6R2O6YU64WX&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyQU8zS09INjAwSjlNJmVuY3J5cHRlZElkPUEwNTk2NzUzMTNQUExWV0EyUlJZRCZlbmNyeXB0ZWRBZElkPUEwODQ4NjkxMkkxSlpMUDhSNFdWRyZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

[UncleTodo]

What are you guys using to measure consumption?
I have a 120v plug in model that can read live A & W draw, boy I wish it draw me a draft A&W, and as well total W usage over an elapsed time.
So this morning it shows .14 KWH over 6.6 hours, which is 14000W divided by 120V for 116.6A?
Seems high to me, or I'm hoping it seems high so I don't need to go with a higher capacity battery.
My AC adapter is rated at 90W and 1-1.5A on the AC side and 3.75A on the 24V DC side.
I'm using this, but maybe there's something better? Although at this point I'd rather start checking 12V usage of things.

Amazon.com

 

[snoobler]

What are you guys using to measure consumption?
I have a 120v plug in model that can read live A & W draw, boy I wish it draw me a draft A&W, and as well total W usage over an elapsed time.
So this morning it shows .14 KWH over 6.6 hours, which is 14000W divided by 120V for 116.6A?
Seems high to me, or I'm hoping it seems high so I don't need to go with a higher capacity battery.
My AC adapter is rated at 90W and 1-1.5A on the AC side and 3.75A on the 24V DC side.
I'm using this, but maybe there's something better? Although at this point I'd rather start checking 12V usage of things.

Amazon.com

0.14kWh = 140Wh

140Wh/6.6h = 21.2W average over that period.

21.2W/120V = 0.18A

 

[UncleTodo]

Thanks, looks like the decimal point got lost in the translation, phew!

 

[CactusBob]

I really like these smart plugs by Emporia for doing energy tracking. History display in the mobile app by your choice of month/day/hour/minute/second. There are 1 packs and 4 packs.

Amazon.com

I like the looks of these, they seem better than the power meter that loses everything every 24 hours. Have ou used these at all?

Bob

 

[CactusBob]

I haven't forgot about this and am still looking forward to getting it built. I think I am going to go with the batteries from the group buy page and build up the box. I should have funds next month or beginning of March to order the batteries.
For a 12v 270 AH battery how much solar would be needed. I read on the site where Will talked about Santan Solar and they are just about an hour up the road. If I figured it out correctly with 500w of solar and if I don't go below 50% SOC I should be able to charge it in about 6 hrs. Does that sound right?

Bob

 

[HaldorEE]

I haven't forgot about this and am still looking forward to getting it built. I think I am going to go with the batteries from the group buy page and build up the box. I should have funds next month or beginning of March to order the batteries.
For a 12v 270 AH battery how much solar would be needed. I read on the site where Will talked about Santan Solar and they are just about an hour up the road. If I figured it out correctly with 500w of solar and if I don't go below 50% SOC I should be able to charge it in about 6 hrs. Does that sound right?

Bob

Wow. That battery should power a CPAP for months.

I figure I can count on 50% of rated panel capacity and 5 full sun hours per day. So 500W solar panels means ~1250 WH of solar input per day. Where will you be using this system makes a huge difference. I live in Arizona so it is probably I will get more than that, but with solar it is better to be pessimistic in your power harvesting predictions than optimistic.

For my E350 van build I have 300W of solar (Renogy 300W panel into a Victron MPPT Smart Solar 100/20), 360W of alternator charging (Victron Orion-TR 12/24-15 Smart Charger) when driving and 1200W of shore power charging (Victron Multiplus 24/2000-50) when an AC outlet is available. If I ever plan on doing any extended boondocking, I will add a ground mounted 300W panel (the MPPT 100/20 is able to handle two 300W panels in series for 580W of max solar input).

That means 750WH of solar input per day (1500WH with two panels). I have 7160 WH of battery capacity (8S, 280 AH) so if I start a trip with the battery topped up, I expect I will be able to handle a solid 3 days of boondocking with just solar input. I won't miss the second panel for road trips, since I have alternator charging.

 

[CactusBob]

Wow. That battery should power a CPAP for months.

I figure I can count on 50% of rated panel capacity and 5 full sun hours per day. So 500W solar panels means ~1250 WH of solar input per day. Where will you be using this system makes a huge difference. I live in Arizona so it is probably I will get more than that, but with solar it is better to be pessimistic in your power harvesting predictions than optimistic.

For my E350 van build I have 300W of solar (Renogy 300W panel into a Victron MPPT Smart Solar 100/20), 360W of alternator charging (Victron Orion-TR 12/24-15 Smart Charger) when driving and 1200W of shore power charging (Victron Multiplus 24/2000-50) when an AC outlet is available. If I ever plan on doing any extended boondocking, I will add a ground mounted 300W panel (the MPPT 100/20 is able to handle two 300W panels in series for 580W of max solar input).

That means 750WH of solar input per day (1500WH with two panels). I have 7160 WH of battery capacity (8S, 280 AH) so if I start a trip with the battery topped up, I expect I will be able to handle a solid 3 days of boondocking with just solar input. I won't miss the second panel for road trips, since I have alternator charging.

I live in Southern AZ so yeah we have abundant sunlight. Once done, this system is for when we go camping, or power outages, and will run two cpaps, charge phones and maybe a light or two so probably a little overkill for now. When retirement gets here, hopefully soon, we are going to travel full time for awhile so it will also power anything else I need in a rv/trailer or whatever we end up with. I saw Will mentioned SanTan solar on the website and its right up the road, since I will be in Phoenix Friday I may stop in and see what they have. Since mine will be ground mounted, at least for now I need to make sure we are able to move and set them up.

Bob

 

[snoobler]

30 day kill-a-watt results (includes idle power consumption):

Resmed S9 Autoset

kWh: 8.95

Max temp
Max humidity
11.8 pressure
5.4 average hours sleep/night

What did this teach me?

I need way more sleep.

 

[jpcjtrtj]

Here’s what I just built; I’ll let you know how it works in a couple weeks. I have the Resimed 10. Last post in this string.

Building a CPAP battery backup

In the next week or two I am going to start the process for building a battery backup for mine and my wife's Cpap systems. This is for off grid and when power goes out. They both draw about 150 watts a night and will run from 12v. That should go down once I move to 12v. In addition when I am...

diysolarforum.com

 

[nifty-stuff.com]

Hey All! I did a search for all threads with "cpap" in the subject line and read a handful of them... and this one was the longest and had the most details, so hopefully it's also the best place to post my question!

The SF Bay Area has had a lot of blackouts and my girlfriend's elderly Grandfather wants a battery backup for his ResMed AirSense 10 Elite CPAP machine.

From what I'm reading, there are a few things I'm contending with:

1. He wants it to basically act like a UPS where he's got it plugged in all the time, and if power goes off, it will still be functioning just fine (from what I understand, most power systems / boxes will turn off if not pulling current, so he'd have to manually turn on the power box, no?)
2. He'd like it to last 2-3 days with the humidity / heater on (if I'm reading the threads correctly, this uses about 200Wh per night)
3. This unit uses 24v (I could use a 12v DC to 24v DC voltage converter... but I think the plug is weird... see my next point)
4. It has a proprietary plug (I think there are some on Amazon that plug into cigarette lighter adapters and also do the 12v to 24v conversion)

Again, this isn't for camping, and ideally he could always just have it plugged in and working off the battery... with some kind of always-on pass-through charging from a wall adapter to the battery, then the battery to DC 24 volts (either using a cheap 24v up-converter or one off amazon)... but I'm not sure if this is the way to go?

So, what would you do? Would one of the "solar generators" like the Ecoflow, Bluetti, etc. work, or are they not designed to be on 24/7 and only pushing power 8 hours a night?

THANK YOU!!!

 

[Philfr]

I am thinking of using lifepo4 batteries to build the battery bank for the cpap. It is more expensive but it saves a whole lot of weight I don't feel like lugging around. The AGM's I have seen weigh about 24lbs for 35AH battery. Plus its much easier to find an inexpensive case to build with 18650's than an AGM.
If building a 12v system is it better to build it as a 3s or 4s, or is it better to build a 24v system and use a dc to dc converter to drop it to 12v.

Thanks
Bob

Hey All! I did a search for all threads with "cpap" in the subject line and read a handful of them... and this one was the longest and had the most details, so hopefully it's also the best place to post my question!

The SF Bay Area has had a lot of blackouts and my girlfriend's elderly Grandfather wants a battery backup for his ResMed AirSense 10 Elite CPAP machine.

From what I'm reading, there are a few things I'm contending with:

1. He wants it to basically act like a UPS where he's got it plugged in all the time, and if power goes off, it will still be functioning just fine (from what I understand, most power systems / boxes will turn off if not pulling current, so he'd have to manually turn on the power box, no?)
2. He'd like it to last 2-3 days with the humidity / heater on (if I'm reading the threads correctly, this uses about 200Wh per night)
3. This unit uses 24v (I could use a 12v DC to 24v DC voltage converter... but I think the plug is weird... see my next point)
4. It has a proprietary plug (I think there are some on Amazon that plug into cigarette lighter adapters and also do the 12v to 24v conversion)

Again, this isn't for camping, and ideally he could always just have it plugged in and working off the battery... with some kind of always-on pass-through charging from a wall adapter to the battery, then the battery to DC 24 volts (either using a cheap 24v up-converter or one off amazon)... but I'm not sure if this is the way to go?

So, what would you do? Would one of the "solar generators" like the Ecoflow, Bluetti, etc. work, or are they not designed to be on 24/7 and only pushing power 8 hours a night?

THANK YOU!!!

I had same challenge, and also wanted to boondock in RV with cpap, and also wanted an emergency generator in case of power outage. After a lot of research, I bought the Bluetti AC200max and it has been great. It has AC, DC, and 30 amp output . I’ve had the CPAP machine plugged into it the past few nights as the storms roll through, I can put it in my RV and run my cpap and also if I want I can run my RVs 30 amp utilities off of it, and also occasionally hook it up to the washing machine or dryer during Peak electric rates periods. Of course, I can recharge the Bluetti either by plugging into AC or through solar inputs. It’s heavy to lug around, but I bought a cart off Amazon, where it spends most of its time. I can’t say enough about it and highly recommend it.