My battery backup setup

[verbatim1]

....or new engineer that liked the new one better.

I've been there. Some new engineer is bent on using the latest processor in a satellite system; and I have to tell 'em NO. Your part will be dead at 10 kilorads; and the dose-depth kernel is asymptotic at 25 kilorads. (i.e. -- no amount of shielding will get the part exposed to less than 25 krad over mission life; and it'll be dead at 10 krads.)

Hi Mongo,

We're both (different kinds of) engineers, and a lot depends on the companies we work at, but I've been at a half dozen very large companies where the engineers NEVER are allowed to make major decisions.

I was at a very small company though, where the engineers made MANY of the major decisions, so, we really need to ask whether at ResMed and Philips (and whatever other CPAP companies service us), the engineers or the executives make such decisions.

Do we know the answer?

At the CPAP manufacturer, is the decision to make the power supply hugely non standard a mostly engineering decision or is it a mostly MARKETING decision?

• It's mostly marketing decision?
  
• It's mostly an engineering decision?
  

Of the main brands, which made the decision to require their own hugely non-standard power supplies?

• Resmed = all new models are non standard (is that correct?)
  
• Philips = some new models are non standard (is that correct?)
  
• Fisher & Paykel = ?
  
• DeVilbiss = Standard 12 V battery using a standard plug.
  
• Aeiomed = ?
  
• ProBasics = ?
  
• Puritan Bennett = ?
  
• Human Design Medical = ?
  
• (Did I miss any major manufacturers?)
  

[verbatim1]

commented about the difficulty of using a Resmed on battery. The RT on duty suggested, well just buy the battery, pointing to a display.

Hi Sleeprider,

What's sad is that I'm sure people BUY that super-expensive ResMed branded battery, simply because the people they TRUST tell them what that RT told you.

You were smart enough to disagree with the RT on his "advice"; but how many people are smart enough to ignore the advice of their trusted RT?

ResMed makes a killing on those batteries, I'm sure, simply because many people are AFRAID of making the decision you made so logically.

I looked at the packaging, and it was a 12 volt battery, so I scoffed, "So the battery you sell is $350, and I would still need an expensive 12V-24V up-converter adapter.

Again, you were smart enough to disagree with the RT on his "advice"; but how many people are smart enough to ignore the advice of their trusted RT?

ResMed (and that RT) make money off of people's fears and their misplaced trust in the RT's (and ResMed's) advice.

The good news is, I confirmed I'm no longer monitored for compliance, and can use my PRS1 machines when camping. Problem solved.

May I ask why you are "monitored for compliance"?
(What did you do wrong?)

More importantly for me, am "I" monitored for compliance,?
How would I know?

(Note: I have had my brand new ResMed A10 on airplane mode ever since I got it a few weeks ago, but I put it in airplane mode only because I am a privacy advocate on all my electronic devices - not because I'm being monitored (to my knowledge, I'm not, but that's why I ask you the question).

[OMyMyOHellYes]

Of the main brands, which made the decision to require their own hugely non-standard power supplies?

• Resmed = all new models are non standard (is that correct?)
  
• Philips = some new models are non standard (is that correct?)
  
• Fisher & Paykel = ?
  
• DeVilbiss = Standard 12 V battery using a standard plug.
  
• Aeiomed = ?
  
• ProBasics = ?
  
• Puritan Bennett = ?
  
• Human Design Medical = ?
  
• (Did I miss any major manufacturers?)
  

Have I ever mentioned that I like DeVillbiss? They seem to get the customer.

OMMOHY

[verbatim1]

Okay so rife with speculation and the same old "If I can't think of any other reason then it must be what I think it is." This is not logic or scientific in any way.

Hi PoolQ,

Just because I provided a logical argument (admittedly with minimal substantiation) that directly counters your (completely unsubstantiated) argument, doesn't make mine "speculation" and yours fact.

YOU SAID: They did it for liability reasons.
I COUNTERED: Plenty of others have the same liability and they don't do it.

You call my logic "speculation"; while you assume yours is not.

Be advised I am nothing but logical.

I am trained as both a scientist and as an engineer, with all the higher-level sheepskins to prove it, where I certainly have been taught the difference between "speculation" and "logical" reasoning.

You actually have your adjectives reversed, since you haven't justified your speculation in the least, while I, at the very least, gave a viable counter argument that holds water.

It may simply be that you may not believe nor understand the logical reasoning I applied to counter your argument (that they did it for liability reasons), but if you simply don't believe nor perhaps understand my logical reasoning, that doesn't make your opinion fact and mine "speculation".

So please, don't call the kettle black when you, yourself, are merely speculating wildly. Your very words are an affront to logical thought processes.

I'm seeking facts and logical thought processes.

Since nobody from ResMed is going to call us up to tell us why they went non standard, we are going to have to logically reason this one out on our own, based on the facts that we know.

What facts do we know?
I am not afraid of facts.

To that end, I will list the following statements as "facts" that (I think) we know; but, if ANY of them are wrong - I ask anyone who knows more than I do to CORRECT them - because, as with all science and engineering - the truth is in whether the statements withstand the scrutiny of a public review.

For example, a review of the patent shows that the patent was NOT IMPLEMENTED fully; it was only (apparently) implemented just enough to make the equipment non standard (e.g., there does not seem to be evidence of any other resistor value used other than the 2.7K Ohm resistor).

Facts are facts.

So, my statements either hold up to public scrutiny - or they don't.
I'm OK with that.
I just want to get to the truth.

WHAT ARE THE FACTS WE KNOW & their logical intimations?

• We know that other manufacturers use standard power supplies
  
• We know what the ResMed patent "says" about sensing the power supply wattage (and subsequently, about prioritizing inspiration power)
  
• We know that ResMed does NOT follow the patent except in a single case (which we can logically intimate is just enough to make their A10 power supply non standard)
  
• We know that ResMed's batteries are horrendously overpriced for a 12 volt battery (although the pack is a nice package)
  
• We know that a DC-to-DC up converter is a commodity, except in the ResMed case, because of the non-standard power plug
  
• We know (from basic economic theory coursework) that Marketing always tries to convert a commodity into a monopoly (if they can get away with it)
  
• We know that RTs recommend ResMed's horrendously overpriced batteries and DC-to-DC converter (e.g., Sleepster just ran into that)
  
• We can logically intimate that "most people" trust their RT's advice
  
• Therefore we can logically intimate that people are paying more by following the monopolistic advice of their RT to use ResMed's highly priced battery and converter than if they bought the associated commodities
  

NOW WE COME TO THE CRUX OF THE ISSUE:

If there is actual VALUE TO THE USER directly attributed to the non-standard power supply, that would be the most valuable input this thread could ever receive!

While you might counter that the motor is painted pink inside, that is not a direct association to the design decision of using a non-standard power supply.

The motor might be faster, slower, more steady, lighter, heavier, cheaper, etc, but if that feature is not [u]directly associated with the non standard power supply[/b], then that feature is merely a difference, and not a difference attributable to the design decision of going with the non-standard power supply.

At the moment, nobody has proposed any concrete value that EXISTS that is directly associated with the highly non-standard power supply.

BTW, since you seem to be rather confused about facts versus speculation, that is either a true statement - or it is a false statement.

You tell me.
Is that statement above true or false?

I am honestly seeking a concrete association of the non-standard supply with an actual EXISTING BENEFIT (to the user) in the equipment.

[PoolQ]

Well I have no doubt that you have a very extensive engineering background, this is obvious by the content of your posts. You are however making some large assumptions of what my background may or may not be. You are incorrect.

24VDC is a very standard adapter voltage, their power plug though is not.
You want non-standard- my laptop adapter is 19VDC and I know of no one that has said that even at the premium for a name brand adapter that this is some marketing conspiracy.

I have been responsible for bringing products to the market as well as safety certifications, and market segmentation, product positioning, and a host of other marketing efforts. I have had the questionable pleasure of meeting with corporate lawyers about product liability for many products and making them happy was strange indeed. Yes while I have over 15 years of engineering, including reliability engineering, I also do ethical marketing of products (I do not pray on customer ignorance and lack of knowledge to get them to buy my products).

I understand your logic from the consumer point of view and I was never talking about that, I was talking about the manufacturers point of view. I stand by everything I said.

If you disagree, that is fine, nothing I said was personal and I know that I never called you out in anything I said.

According to Webster: speculation is -ideas or guesses about something that is not known.
Logical or not, true or not, accurate or not- neither of us know what guides the pricing of these products or the selection of voltages, we are BOTH speculating and are offering our opinion of the motivations of a company that we personally have no direct knowledge of.

"BTW, since you seem to be rather confused about facts versus speculation, that is either a true statement - or it is a false statement" unless you work for Resmed or have been a contractor for them anything you say about why they did what they did is speculation, it may however be accurate speculation.

It seems that you took my post personally and I apologize if you did, I did not intend in any way to question you professional standing or ability to logically evaluate motivations. Translating that logic into fact however is another story.

This thread was about how to provide cost effective battery backup for Resmed CPAP machines and I do not think it is relevant to this subject to spend so much time speculating as to why Resmed made the choice it did as this does not advance the primary subject. It seems more like bashing a major manufacturer of CPAP equipment and in this context I do not that that this line of conversation is educational and in line with this website.

[Sleeprider]

May I ask why you are "monitored for compliance"?
(What did you do wrong?)

More importantly for me, am "I" monitored for compliance,?
How would I know?

(Note: I have had my brand new ResMed A10 on airplane mode ever since I got it a few weeks ago, but I put it in airplane mode only because I am a privacy advocate on all my electronic devices - not because I'm being monitored (to my knowledge, I'm not, but that's why I ask you the question).

I received my new Aircurve 10 Vauto in February this year. Insurance does not pay until it is determined I am both compliant with the therapy and my physician agrees it is beneficial. I have now passed the period where that proof is required. Normally someone getting a machine after many years of treatment is not required to show compliance, but in my case, I was upgrading to bilevel, and insurance was being picky.

If your machine is paid for and the account settled, you are not subject to compliance. You can always ask the DME.

[verbatim1]

Insurance does not pay until it is determined I am both compliant with the therapy and my physician agrees it is beneficial.

Wow. Thanks for answering that, which, I agree, amounted to a personal question, off topic for this particular thread.

My insurer, Kaiser, simply handed me a ResMed A10 after one night with a finger cuff (92 events per hour), and a week of titration at home (0 to 20, automatic), where, AFAIK, they do not "monitor" my compliance.

Of course, with 92 events per hour sans CPAP, I'd be a darn fool to NOT be compliant; but still, I was unaware of such draconian actions.

Thank you for explaining. The reason I asked is that, being a privacy freak, I immediately turned off the Verizon CDMA modem the moment I learned that it existed on the A10.

I have now passed the period where that proof is required. Normally someone getting a machine after many years of treatment is not required to show compliance, but in my case, I was upgrading to bilevel, and insurance was being picky.

Now I understand.
Sorry for asking a personal question.
If you like, I can ask the mods to delete my question and your answer.

If your machine is paid for and the account settled, you are not subject to compliance. You can always ask the DME.

Thanks for that advice. I barely know the "DME'.
I simply went to a doctor that Kaiser said to go to, and I never once saw a real doctor. I met with a tech briefly when he explained the finger cuff, and again when the same tech explained the Respironics titration loaner, and a third and last time when he handed me the ResMed A10.

That's a sum total of about a half hour in non-medical all-machine-related meetings, never once with a "real" doctor.

Back on topic, as an engineer, I was asked a few times to make things non standard so that the company would have a competitive edge, and, most of the time we back ported such things as security keys and hard-coded calls, just to make what would have been standard stuff, non standard.

I hated doing that; but it was my job, so, I'm fully able to comprehend that another company would use the guise of a patent to implement "just enough" of the patent to make their equipment non standard.

It would be helpful if we found any evidence whatsoever that ResMed has implemented MORE than just the single resistor sense circuit, for example. That would be in keeping with the patent's stated purpose. Without a second sense resistor indicating a LOWER wattage power supply, the patent's true purpose is easily questioned.

Since I innately abhor the "walled garden" marketing philosophy, I have ALREADY taken your advice, and obtained a second STANDARD-POWER-SUPPLY machine, as shown in this thread.
http://www.apneaboard.com/forums/Thread-...amping-use


But, it's still of interest to me to understand how to design and build the duplicate ResMed A10 power supply, especially since the design seems patently simple.

[verbatim1]

This thread was about how to provide cost effective battery backup for Resmed CPAP machines and I do not think it is relevant to this subject to spend so much time speculating as to why Resmed made the choice it did

Hi PoolQ,
You seem like a reasonable fellow, and I agree mostly with you that we should concentrate on how to design and build the circuit.

We might need to understand WHY they did what they did, but only if it matters to the circuit.

With that in mind, I reproduced the rudimentary single-diode circuit below using the suggested DipTrace Windows freeware.

I'm not sure how to upload the 30KB binary DipTrace "*.dch" file though, so, I will do that when I find a web site that allows arbitrary file types to be uploaded.

That way, others can pick up exactly where we left off.

Check out DipTrace. It's what I use and there's a freeware version.

Thanks for the suggestion of using Diptrace freeware schematic editor on Windows.

Here is a screenshot of that rudimentary (single Schottky diode) schematic.

How can I upload the 30KB binary schematic.dch file so that others can use it from where I left off?

EDIT: I googled for a free no-registration file uploader, and this is one that I used, but I don't know how good it is so be wary of using it until we know it works well.

The schematic is 30KB, named "schematic1.dch" located here:
https://www.sendspace.com/file/colzda

DOUBLE EDIT:
Here is the schematic2.dch with the Schottky diode bridge in place:
https://www.sendspace.com/file/7x4dx2

[PoolQ]

I was looking at MPPT solar chargers today and you can put two 12V panels in series, charge two 12V batteries in series and power a 24V load, everything is automatic except AC power and auto switch over for that. Camping might be workable with the above and the circuit here

[justMongo]

The bridge is incorrectly hooked up; and the resistor should be 2.7K