M-series Auto power use data for battery DYI

[feeling_better]

I measured the 12v DC power used by my Respironics M-series Auto machine. This data may be useful if you are designing your own battery backup or estimating how long a battery would last.

Note 1. The power consumption goes up as the flow increases, for a specific pressure. This means when there are leaks the power needed will increase too. The measurement data below was done with a Switf LT nasal pillow, when there is no unintended leak.

Note 2. There is a very high initial current needed when flow starts, for a couple of seconds. This may be as high as 2A. If the voltage drops even 0.5v at that initial time (below about 12v), the machine simply will shut down the flow!!

Note 3. This is not for the 110v AC side of the power brick, people using UPS like boxes cannot use these numbers directly.

Note 4. The humidifier is always off for these, since the humidifier does not work on 12v DC, but needs 110v AC.

Edited: The following was measured at approximately sea level.

Current Pressure
mA cm
~320 4.0
~360 7.0
~390 10.0
~420 13.0 (estimated)

When the above mask is taken off, (when air is freely flowing from the pillows), the consumption will go up to about 1 Amp.
When the blower is not running, it takes about 200 mA.

So with the varying unintended leaks we always have, and the variations in the intended leaks of different mask models, I estimate the average consumption may be about 400-700 mA, depending on your pressure, leak, mask type.

[RosemaryB]

Very interesting info. Thanks for posting.

[billbolton]

Current Pressure
mA cm
~320 4.0
~360 7.0
~390 10.0
~420 13.0 (estimated)

Useful information!

Can you please confirm the altitude you were at when making the readings, and if known, what altitude setting the flow generator was on (if it wasn't working out altitude automatically).

The altitude setting does impact how much energy the flow generator uses, as when the ambient air pressure is lower, the pump has to work harder.

Cheers,

Bill

[feeling_better]

Current Pressure
mA cm
~320 4.0
~360 7.0
~390 10.0
~420 13.0 (estimated)

Useful information!

Can you please confirm the altitude you were at when making the readings, and if known, what altitude setting the flow generator was on (if it wasn't working out altitude automatically).

Sea level, for all purposes.