Nice CPAP battery bank that isn't too pricey.

[Oughtsix]

I was looking for a new CPAP battery for camping this year since I am getting kind of tired of carrying around a lead acid car battery. I came across this battery bank that seems perfect so I ordered one. BYOB (Bring Your Own Batteries!)

What I like is that is relatively cheap ($57), fully voltage regulated, you use your own 18650 batteries and you can run it on 3x, 6x, 9x, or 12x - 18650 batteries so you can customize your capacity depending on how long you need it to last and whether you use the humidifier heater or not. If you aren't familiar with 18650 batteries they are the Li-Ion batteries that power pretty much everything these days: cordless tools, laptops, Tesla cars, Flashlights, VAP pens, etc. You can buy expensive Samsung, Panasonic or Sony top end super high capacity 18650 batteries that would easily drive a CPAP for a few weeks or cheap Chinese 18650 batteries that should still last a week if you fill up the bank with 12 of them.

Since the output is adjustable from 12v - 24v you should even be able to use this for the older higher voltage Philips models. It also has a QC3 (Quick Charge 3) port for quick charging your cell phone.

https://www.amazon.com/gp/product/B08LN ... UTF8&psc=1



MAKE SURE TO ORDER THE "B" VERSION!





I will post my impressions when I get the battery bank in. I believe it is coming from China so I am not getting Amazon's usual speedy delivery.

P.S. I am so tempted to use this battery bank with my CPAP on an airplane so I don't have to breath airplane air!

[ChicagoGranny]

P.S. I am so tempted to use this battery bank with my CPAP on an airplane so I don't have to breath airplane air!

How will you attach the CPAP to a wing?

[loggerhead12]

Cool. Let us know how many amp hours you get out of the thing with what kind of batteries. And when they start building one in the US.

[chunkyfrog]

P.S. I am so tempted to use this battery bank with my CPAP on an airplane so I don't have to breath airplane air!

How will you attach the CPAP to a wing?

Maybe they will let him put it next to an open window . . .

[Oughtsix]

P.S. I am so tempted to use this battery bank with my CPAP on an airplane so I don't have to breath airplane air!

How will you attach the CPAP to a wing?

Double sided tape... Of course!

[zonker]

P.S. I am so tempted to use this battery bank with my CPAP on an airplane so I don't have to breath airplane air!

How will you attach the CPAP to a wing?

Double sided tape... Of course!

[palerider]

You can buy expensive Samsung, Panasonic or Sony top end super high capacity 18650 batteries that would easily drive a CPAP for a few weeks or cheap Chinese 18650 batteries that should still last a week if you fill up the bank with 12 of them.

Tesla uses 2170 cells in the model 3.

Your calculations are wrong with respect to capacity.

If you put 3.5ah 18650s in this, (in a 3s4p configuration), you'd get a *maximum* of 151.6wh, which is less than 1/3rd of what a 35ah lead acid battery will give you.

Average usage of a CPAP, without any heat for humidity or hose is around 80wh a night, depending on pressure, so you might, almost, maybe if you're lucky, get two nights out of the very best cells on the market today.

But it should get you through that airplane ride....

No idea where you're going to get "non-airplane" air, though, you're on your own for that.

I will say that they frown on it if you take a hole saw to one of the windows, (irrespective of the fact that there's a partial vacuum out there at cruise).

[Oughtsix]

Cool. Let us know how many amp hours you get out of the thing with what kind of batteries. And when they start building one in the US.

These are the batteries I went with:
https://www.imrbatteries.com/sanyo-ncr1 ... a-battery/
12 for $66

SPECIFICATIONS:

Manufacturer: Sanyo
Model: NCR18650GA
Size: 18650
Style: Flat Top
Nominal Capacity: 3400mAh, typical
Discharge Current: 10A Maximum Continuous
Nominal Voltage: 3.6V
Maximum Voltage: 4.2V
Approximate Dimensions: 18.5mm x 65.3mm
Approximate Weight: 48g
Origin: Japan
Specification Datasheet: Sanyo NCR18650GA Datasheet

Which are as good as you are going to get with any packaged battery bank and a whole lot better than most of the packaged battery banks, especially the cheap ones. That battery store has a very good reputation of selling good name brand cells instead of fakes. I could have picked up a set of 12 batteries off of Amazon for about half the price but they wouldn't have near the life.

I have many various 18650 batteries, some named brand, some Chinese cheapies. I wanted a matched set for this power bank. Unmatched batteries in parallel are unbalanced which causes the whole bank to underperform. I do have other uses I am planning on using this battery bank for so it is worth investing in some quality cells... for me.

P.S. If you want to know which batteries are good batteries ask a Vapor! I don't and have never VAP'd but those guys know their batteries! It is almost like batteries are an addiction with them!

[Oughtsix]

You can buy expensive Samsung, Panasonic or Sony top end super high capacity 18650 batteries that would easily drive a CPAP for a few weeks or cheap Chinese 18650 batteries that should still last a week if you fill up the bank with 12 of them.

Tesla uses 2170 cells in the model 3.

Your calculations are wrong with respect to capacity.

If you put 3.5ah 18650s in this, (in a 3s4p configuration), you'd get a *maximum* of 151.6wh, which is less than 1/3rd of what a 35ah lead acid battery will give you.

Average usage of a CPAP, without any heat for humidity or hose is around 80wh a night, depending on pressure, so you might, almost, maybe if you're lucky, get two nights out of the very best cells on the market today.

But it should get you through that airplane ride....

No idea where you're going to get "non-airplane" air, though, you're on your own for that.

I will say that they frown on it if you take a hole saw to one of the windows, (irrespective of the fact that there's a partial vacuum out there at cruise).

Elan Musk wants to convert the whole world to 21700's for their greater power density. He even invested in a Li-Ion battery plant to guarantee a supply of 21700's for his new Tesla's. All of the original Tesla models are built around 18650 batteries though. If you really want to go to town they make a 21650 version of this same battery bank. Although the power storage of 21650's is considerably better, the Ah per $ is considerably less. Same with the 21700's. Some day that will change to favor the bigger batteries when they are more widely adopted and more widely produced but today the 18650's are the sweet spot for Ah per $.

At the end of last summer I cobbled together a 9 x 18650 unregulated pack and got 5 nights out of it camping with my Philips System One with the humidifier attached but the heater turned off and the pack of 9 random unbalanced 18650 batteries still had some charge left. After actually using a DIY 18650 pack I am confident I will get MUCH more than two nights out of this battery bank. But, if I don't, I will come back here and eat some Crow! I would rather be wrong and admit it than put out bad information. Of course, I am talking about running my CPAP directly off battery power... not through an inverter and then an AC power supply which would be very inefficient and silly.

BTW: What kind of cells do you think they put in those expensive CPAP battery banks? I would bet many of them, if not most of them, have 18650 cells. The ones with the built in inverters are just crazy IMHO.

[SDBud]

https://www.amazon.com/gp/product/B08LN ... UTF8&psc=1

I will post my impressions when I get the battery bank in. I believe it is coming from China so I am not getting Amazon's usual speedy delivery.

P.S. I am so tempted to use this battery bank with my CPAP on an airplane so I don't have to breath airplane air!

Looks nice, but only 1 rating so far, with no actual review. And the 3 week plus shipping is not great as well.

[mowog73]

I've just started looking into a battery to power my Resmed AirMini and this is an interesting option.

The problem I am having is finding the power cable with the right connector to go into the AirMini. The places I have found so far will only sell it to me if I have one of their battery packs already. I wouldn't think that the connector is proprietary but no luck finding it so far.

[Dog Slobber]

Elan Musk wants to convert the whole world to 21700's for their greater power density.

There is no significant difference in energy density between 21700 and 18650s.

Any measurable difference between 21700 and 18650s in energy and energy density can be attributed to level of material and electrodes.

https://iopscience.iop.org/article/10.1149/2.0281814jes

[palerider]

Elan Musk wants to convert the whole world to 21700's for their greater power density.

There is no significant difference in energy density between 21700 and 18650s.

Any measurable difference between 21700 and 18650s in energy and energy density can be attributed to level of material and electrodes.

https://iopscience.iop.org/article/10.1149/2.0281814jes

Eh? from the article:

(1)
The energy content per cell can be higher by ~50% for 21700 compared to 18650. Therefore, for certain applications, less cells have to be built and used to deliver the same amount of energy.

I've got a 26650 in one of my power banks, it's rated at 18wh, or 5ah.
Size does, it appears. matter.

[Oughtsix]

I've just started looking into a battery to power my Resmed AirMini and this is an interesting option.

The problem I am having is finding the power cable with the right connector to go into the AirMini. The places I have found so far will only sell it to me if I have one of their battery packs already. I wouldn't think that the connector is proprietary but no luck finding it so far.

This looks promising at $29. https://cpapsupplies.com/bps-airmini-ou ... DfEALw_wcB


I purchased the power cable I am using off of ebay for about $20. It is a 12v cigarette jack to Philips System One cable. The connector is pretty unique. I used a 12v female cigarette lighter lighter cable I had lying around to connect it to my DIY battery pack instead of cutting off the end and wiring it directly. When I used a car battery I used a 12v female cigarette lighter cable with alligator clamps on the other end to just clamp onto the battery posts. This allowed my to easily use the cigarette cable when sleeping in an RV instead of a tent.

Sorry I can't help with the ResMed Air mini cable. That cable does look right when comparing it to the pictures of a Resmed cable but I really do not know.

Two very common 12v barrel connectors are 5.5 x 2.5mm and 5.5 x 2.1mm. With 5.5mm being the outside diameter and 2.5mm or 2.1mm being the inside diameter (the hole in the center of the connector). That cable appears to have one of those two connectors on the other end. If you don't want to cut that cable apart 5.5 x 2.1mm and 5.5 x 2.5mm female connectors are very common and can be ordered off Amazon for a couple $. According to the specs the power bank I linked to uses the very common 5.5 x 2.1mm barrel power connector as its output jack. With that cable I think the worst you would have to do is purchase a male 5.5 x 2.1mm to female 5.5 x 2.5mm adapter cable. But it might just plug into the above power bank directly with no adapter needed if that is a 5.5 x 2.1mm connector on the end of the cable.

[Oughtsix]

Elan Musk wants to convert the whole world to 21700's for their greater power density.

There is no significant difference in energy density between 21700 and 18650s.

Any measurable difference between 21700 and 18650s in energy and energy density can be attributed to level of material and electrodes.

https://iopscience.iop.org/article/10.1149/2.0281814jes

Eh? from the article:

(1)
The energy content per cell can be higher by ~50% for 21700 compared to 18650. Therefore, for certain applications, less cells have to be built and used to deliver the same amount of energy.

I've got a 26650 in one of my power banks, it's rated at 18wh, or 5ah.
Size does, it appears. matter.

I threw this conversation off by using the term "power density". 26650's do store more energy because they have a bigger volume. Dog slobber was correct though that the "power density" for a Li-Ion cell is pretty much the same across different sized cells. What the 21700 battery allows Elan Musk to do is pack fewer cells in his battery pack tighter together so the "power density" of the entire battery pack is greater even though the "power density" of the individual cells are pretty much the same between 18650's and 21700's. Since Elan can use fewer of the 21700 cells to store the same energy as a larger number of 18650 cells the overall volume of the battery pack is smaller. How is that for clear as mud?


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BUT!... if we really want to split hairs the "power density" of 21700 cells is greater than the "power density" 18650 cells. This is due to the ratio of volume(and weight) of the actual battery material (anode, cathode and electrolyte) to the volume (and weight) of the inert packaging materials that keeps the battery together.