Do Travel CPAP machine really require an Inverter when off-grid?

[bjackman]

When camping I use by GoodNight 420G with 2 BPS c-100 batteries and that setup have worked well for years. Unfortunately my machine is dying and I need a new machine.

Online I have been looking at the following machines
Somnetics Transcend 3 and their newer Transcend 365
Human Design Medical Z2
Philips Respironics DreamStation

*all below information I pulled from cpap.com website.
Somnetics:
For the Transcend 3 in order to use my BPS battery packs they specify that I need a 150 watt sine invertor.
They do however offer a "Transcend DC Mobile Power Adapter Second Gen" (https://www.cpap.com/productpage/transc ... apter-revA) for use with a DC power source.
Do anybody know if you "must" use the DC power adapter or can you connect directly from battery to machine like their P<n> batteries do?

For the Transcend 365 they only offer a newer P10 battery option. But again since both the 3 and 365 have battery options do you have to use Somnetics batteries or their power adapters or can I use my existing battery packs?

Z2:
The Z2 like the Transcend 3 states that to use the Freedom battery a sine invertor is required, but Z2 offers the following "DC Power Cord for Z1 and Z2 CPAP Machines"(https://www.cpap.com/productpage/human- ... power-cord) for use with DC power. This cord (unlike Somnetics with is an "adaptor") appears to plug the machine directly into a DC power source. So does the Z2 require the sine invertor or is "the man" just trying to oversell me products I don't really need?

Phillips Respironics:
The Dreamstation offers the following: "DreamStation 12V Power Adapter for C-100 & Freedom CPAP Travel Battery Packs" (https://www.cpap.com/productpage/c-100- ... -converter) specifically for use with BPS batteries. But like the Z2 above they ALSO offer the following: "Shielded DC Cord for DreamStation CPAP Machines" (https://www.cpap.com/productpage/pr-dre ... ed-dc-cord) indicating that the machine supports direct machine to DC power.

All 3 of the above offer some form of proprietary (think overpriced) battery option and to me all this confusion is an attempt to get patients to purchase their extra add ons when in fact any "normal" DC power source (like the BPS packs) will suffice.

Does anybody have any experience with any of the above machines and portable power (I am not looking at AGM and other heavy battery options) Any help or information would be appreciated.

Thank you
BJackman

[CapnLoki]

...
Phillips Respironics:
The Dreamstation offers the following: "DreamStation 12V Power Adapter for C-100 & Freedom CPAP Travel Battery Packs" (https://www.cpap.com/productpage/c-100- ... -converter) specifically for use with BPS batteries. But like the Z2 above they ALSO offer the following: "Shielded DC Cord for DreamStation CPAP Machines" (https://www.cpap.com/productpage/pr-dre ... ed-dc-cord) indicating that the machine supports direct machine to DC power.
...
Does anybody have any experience with any of the above machines and portable power (I am not looking at AGM and other heavy battery options) Any help or information would be appreciated.

I frequently use a DreamStation off-grid with the 12V cord. I usually plug into the 12V house bank on my boat (golf cart batteries) and sometimes an AGM battery at home. However, any 12v source that can supply over 50 watt-hours (4 amp-hours at 12v) will get you through the night. There are a number of lithium packs, ranging from 100 watt-hours (usually designed for airline travel) up to 500 watt-hours (designed for powering tablets and cell phones when camping). For home (or boat or RV) an AGM is the best bet and certainly the cheapest. If you give us a hint of your needs, we could give better advice.

[bjackman]

Thank you CapnLoki. I contacted BPS about this question. (paraphrasing)
"...since travel sized cpap machines offer a DC cable option, why can't I use your C-100 or Freedom batteries as the power source?"

There reply was
"The DC cable would not work because these cables are assuming that you are connected to a vehicle which maintains a voltage of 12V-13.6V. The Freedom battery will naturally deplete down below this required voltage (between 10V-12.6V)...So unfortunately, unless the travel device has an open voltage acceptance of 10-12.6V, or we make the proprietary part, the 150W sine wave inverter is the only answer...."

CapnLoki, I realized, from all your posts, thank you by the way, that your situation is a bit different in that you normally do not use the lithium packs I am asking about here, but do you concur with this answer... modern CPAP machines require 12V+ or will they work off of the range mentioned above?

I currently have a Puritan Bennett GoodKnight 420G that is dying. During my last trip, at the hotel I plugged it in and turned it on and got nothing but a hum (sounded like the pump was stuck). After messing with it for awhile I finally "banged" it hard enough (nothing to lose at that point, it wasn't working) and it started working. I need my machine to be dependable and since this machine is old, I got many good years out of it, I am in the market for a new travel machine.

I use this machine for 3 purposes:
1) While traveling where size would be the biggest consideration since I stay at hotels power is not an issue.
2) Camping where I am off-grid.
3) Power outages.
I already have invested in the 2 BPS C-100 batteries that work fine for my needs. During camping I have the ability to re-charge them as needed and at home when storms are expected I use the batteries in-line as backup. For camping I do have 2 batteries so I guess I could "live with" the invertor option but would prefer not to if I don't have to.

So C-100 compatibility followed by Size are my biggest considerations (besides of course reliability, quality, etc...). As I mentioned above I was looking at the Transcend 3 and 365, the Z2 and the Dreamstation. I like the Transcend 365 with the built in humidifier but its DC options appear limited from what info I can find online. The Z2 appears to me to be the most DC compatible but again not sure if it will work with my setup. The Dreamstation sacrifices a little in size, but they do offer the "DreamStation 12V Power Adapter for C-100 & Freedom CPAP Travel Battery Packs" (https://www.cpap.com/productpage/c-100- ... -converter) but I am not sure if that is simply an "Invertor" which of course would reduce battery run time by half.

So that is pretty much my needs, let the "better advice" commence
BJackman