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My battery backup setup
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Marthajoy7 Offline

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Posts: 67
Joined: Jun 2015

Machine: aircurve 10 auto set to bipap S mode
Mask Type: Full face mask
Mask Make & Model: resmed mirage full face or Clear view full mask
Humidifier: Resmed built in humidifier
CPAP Pressure: 18.4/12 clearview or 18/13 mir
CPAP Software: ResScan SleepyHead

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Sex: Female
Location: Seattle

Post: #201
RE: My battery backup setup
The reason you use remote sensors vs just measuring voltage at unit is because voltage loss in the wires can give a false battery low result. By having the resistor as close to the supply as possible and a comparably higher resistance circuit the voltage drop from the wire is minimized and you get a truer result of what the battery condition really is.
I will give you an exaggerated example. You are trying to push 10 amps through 100 ft of wire. The resistance of the wire alone without looking at charts might be say 1 volt lower than at the source. so if sensing voltage at the unit, instead of 24 volts the unit now sees 23 volts, and it thinks the batteries are getting near depletion even though they are still in good shape. By using remote sensing, it still sees the true 24 volt condition of the source because it is not looking at the results of the voltage drop. It is using a sense line to get a truer result of the battery condition.
(This post was last modified: 08-16-2016 03:47 AM by Marthajoy7.)
08-16-2016 03:30 AM
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OMyMyOHellYes Offline

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Posts: 915
Joined: Mar 2013

Machine: Respironics 560 Auto
Mask Type: Nasal mask
Mask Make & Model: Resmed Mirage FX
Humidifier: Respironics System One (no heated hose)
CPAP Pressure: 08.0-15.0 cm/H2O
CPAP Software: EncoreBasic

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Sex: Male
Location: Texas

Post: #202
RE: My battery backup setup
But not needed.

It is there for padding the profit of the manufacturer. These systems don't need to be that complicated.

OMMOHY
08-16-2016 07:40 AM
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surferdude2 Offline

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Posts: 1,077
Joined: Jul 2014

Machine: ResMed S9 AutoSet
Mask Type: Full face mask
Mask Make & Model: Mirage Quattro & Optilife
Humidifier: ResMed H5i @ #3 if nose breathing & #5 if mouth breathing
CPAP Pressure: 12 ~ 20 & 11 ~12 if nasal mask
CPAP Software: ResScan SleepyHead

Other Comments: Late stage 2 emphysema

Sex: Male
Location: Mousetown, Southern Illinois

Post: #203
RE: My battery backup setup
If you read their patent information you will find the reason for what they are doing and how simplistic it is. According to the patent, they have elected to include a fixed resistor inside the power supply brick that has different values for different power supply brick wattage ratings as follows:

1.0k ohms = 30 watt power supply
1.8k ohms = 60 watt " "
2.7k ohms = 90 watt " "
3.9k ohms = infinite watts available

Ergo, if no resistor is detected by the motherboard in the blower, it will not allow the unit to operate.

If a 1.0k ohm resistor is detected, the mobo will allow operation with components connected that will not exceed 30 watts.

If a 1.8k ohm resistor is detected, the mobo will allow operation with components connected that will not exceed 60 watts.

and so on...

That is the simplest and cheapest way they could incorporate some way for the power supply to tell the mobo how much wattage it was capable of delivering thereby making it possible for the processor on the mobo to determine and control how many accessories it would allow to be hooked up when the unit was being used. Simple and cheap, just the cost of a tiny resistor embedded in the power supply brick, a simple resistor bridge circuit on the mobo and a firmware change in the mobo processor.

It follows that the way to utilize these 3 conductor units with some 2 conductor power supply would require that that an outboard resistor of the proper value be connected between the center conductor and the outer braid of the 3 conductor cable. Obviously it should be the proper resistor to match the wattage of the power brick being used in order to maintain the safety feature provided by the new 3 conductor system.

All things considered, it seems like a good and reasonable feature since it prevents the user from overloading the power supply brick, which might result in not getting proper therapy. It also provides a degree of safety against overheating the power supply brick.

Dude
08-16-2016 09:39 AM
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Marthajoy7 Offline

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Posts: 67
Joined: Jun 2015

Machine: aircurve 10 auto set to bipap S mode
Mask Type: Full face mask
Mask Make & Model: resmed mirage full face or Clear view full mask
Humidifier: Resmed built in humidifier
CPAP Pressure: 18.4/12 clearview or 18/13 mir
CPAP Software: ResScan SleepyHead

Other Comments:

Sex: Female
Location: Seattle

Post: #204
RE: My battery backup setup
That does not explain 47K ohm resistor value. I did not read anything like that on the s10. If what you say that line is for, why do you manually have to turn off humidifier and heated tubing when using there 12-24 volt converter. Instruction say you must turn them off yourself. If ir really did that function it would do it automatically. Also if it were looking for a resistor value, It would be just a resistor between center pin and outside. Not a voltage divider circuit.

Sense lines are not something new. Look at just about any Li-mh battery and and you will find 4 connections not just two. + and - like other batteries but also a ground and sense line. It brings both + and - sense lines separately. In 3 wire, the ground and - are combined.
(This post was last modified: 08-16-2016 10:42 AM by Marthajoy7.)
08-16-2016 10:32 AM
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surferdude2 Offline

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Posts: 1,077
Joined: Jul 2014

Machine: ResMed S9 AutoSet
Mask Type: Full face mask
Mask Make & Model: Mirage Quattro & Optilife
Humidifier: ResMed H5i @ #3 if nose breathing & #5 if mouth breathing
CPAP Pressure: 12 ~ 20 & 11 ~12 if nasal mask
CPAP Software: ResScan SleepyHead

Other Comments: Late stage 2 emphysema

Sex: Male
Location: Mousetown, Southern Illinois

Post: #205
RE: My battery backup setup
When you run the system from the 12-24 converter, you have lost the fixed resistor embedded in the power supply since it's no longer connected. That puts you on your own to take care not to connect excessive loads to the converter.

The voltage divider circuitry is inside the blower unit and on the mobo, not in the power supply. Consequently it can determine different values of the single resistor that is embedded in the power supply brick.

As for sense lines on batteries, they are generally connected to a temperature sensor inside the battery to prevent overcharging, which would produce dangerous heat levels.

Dude
(This post was last modified: 08-16-2016 11:28 AM by surferdude2.)
08-16-2016 10:51 AM
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Perchas Offline

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Posts: 38
Joined: Aug 2016

Machine: Philips DreamStation A-CPAP
Mask Type: Nasal mask
Mask Make & Model: Apex Wizard 210 (All Silicon)
Humidifier: Fresh, (Steamless)
CPAP Pressure: 10,5-15,5 cm H2O
CPAP Software: SleepyHead

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Sex: Male
Location: Madrid & Phoenix

Post: #206
RE: My battery backup setup
All passive components work with 5V dc and 3.3 Vdc, no sense feeding a PCB 24 Vdc to reduce both the voltage.

Someone to do this test in the S10 ?, I have a slight certainty that ResMed S10, 12 Vdc work without using the heated humidifier & hose.

I can not identify the PCB two pins Chip, can be a Zener diode.

If it Works with 24 V and 47 k, try 12 V and 20 K, it appears that your AS10 might work at 12 V if the Zener diode deceive.

Try if worked
08-16-2016 11:29 AM
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PoolQ Offline

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Posts: 986
Joined: Jul 2015

Machine: AirCurve 10 VAUTO
Mask Type: Full face mask
Mask Make & Model: Amara View
Humidifier: Integrated
CPAP Pressure: 6.2, 15, PS4.0
CPAP Software: SleepyHead

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Sex: Male
Location: Sillicon Valley

Post: #207
RE: My battery backup setup
Well it gets more interesting, I have read that without any resistor the CPAP will not turn on-how does the DC-DC work without a resistor?
The resistor cannot be a sense resistor because there is little to no current in that lead, it cannot measure the voltage drop in the main power lead
They use 24VDC for the blow motor so they can drop the blow current in half and most likely for the heater also-again half the current. Perhaps this is to save money on MOSFETs or maybe they can get better control and response of the blower with the lower current.
There is obviously a resister in the unit to form a voltage divider because a large value resistor connected to the 24VDC line will work and you don't even need the 3 volt regulator, I am not at all sure that the CPAP could detect the difference between the different wattages when using a large resister because of the large steps between values at that range.
08-16-2016 12:14 PM
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sdb7802 Offline

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Posts: 199
Joined: Jan 2016

Machine: PR DreamStation Auto
Mask Type: Nasal pillows
Mask Make & Model: ResMed AirFit P10
Humidifier: built-in with heated hose
CPAP Pressure: 9.5-14 C-Flex 3
CPAP Software: SleepyHead

Other Comments: Retired Electrical Engineer; began using cpap in 2001; FlashAir wifi card and FlashPAP app

Sex: Male
Location: Georgia, USA (The Margravate of Azilia)

Post: #208
RE: My battery backup setup
(08-16-2016 11:29 AM)Perchas Wrote:  Someone to do this test in the S10 ?, I have a slight certainty that ResMed S10, 12 Vdc work without using the heated humidifier & hose.

If it Works with 24 V and 47 k, try 12 V and 20 K, it appears that your AS10 might work at 12 V if the Zener diode deceive.

My tests on three A10 units shows they require at least 22.3V to power up. Once you start the blower, it will run until you lower the voltage to 20.5V.

(08-16-2016 11:29 AM)Perchas Wrote:  I can not identify the PCB two pins Chip, can be a Zener diode.

Post a high res pic and I will try to identify the component. Which machine?

Just my personal opinion. My posts are not medical advice or a statement of fact. Please consult a qualified physician or other qualified medical personnel. Please comply with all applicable laws, codes, regulations, and protocols.
08-16-2016 12:18 PM
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surferdude2 Offline

Advisory Members

Posts: 1,077
Joined: Jul 2014

Machine: ResMed S9 AutoSet
Mask Type: Full face mask
Mask Make & Model: Mirage Quattro & Optilife
Humidifier: ResMed H5i @ #3 if nose breathing & #5 if mouth breathing
CPAP Pressure: 12 ~ 20 & 11 ~12 if nasal mask
CPAP Software: ResScan SleepyHead

Other Comments: Late stage 2 emphysema

Sex: Male
Location: Mousetown, Southern Illinois

Post: #209
RE: My battery backup setup
I suspect there may be a resistor in the sense line circuit on the new version of the dc-dc converter since it is designed for the 3 wire system. I can't verify since I don't have one to measure. I also can't guarantee that the sense resistor values being used are the same as specified in their patent application. They may have elected to use different values and even use a different method of detecting those values but the process is basically the same. Let's face it, how else can a power supply brick communicate its wattage capability in such a simple manner and make for a simple detection method?

Dude
08-16-2016 12:24 PM
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sdb7802 Offline

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Posts: 199
Joined: Jan 2016

Machine: PR DreamStation Auto
Mask Type: Nasal pillows
Mask Make & Model: ResMed AirFit P10
Humidifier: built-in with heated hose
CPAP Pressure: 9.5-14 C-Flex 3
CPAP Software: SleepyHead

Other Comments: Retired Electrical Engineer; began using cpap in 2001; FlashAir wifi card and FlashPAP app

Sex: Male
Location: Georgia, USA (The Margravate of Azilia)

Post: #210
RE: My battery backup setup
Just an FYI: I've verified that the +3.3V regulator and 2.7k ohm series resistor circuit is actually present in the Resmed AC supply, the Resmed 12 to 24 volt converter, and the BPS 24 volt converter.

Just my personal opinion. My posts are not medical advice or a statement of fact. Please consult a qualified physician or other qualified medical personnel. Please comply with all applicable laws, codes, regulations, and protocols.
(This post was last modified: 08-17-2016 08:20 PM by sdb7802.)
08-16-2016 12:41 PM
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