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HDM Z-1 power consumption?
#1
HDM Z-1 power consumption?
Does anyone know if HDM has a table like Resmed's that shows the power consumption of their units (in amps) at given pressures?

That would be VERY helpful in sizing a battery for more extended emergency usage.

OMM
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#2
RE: HDM Z-1 power consumption?
(02-01-2015, 09:32 AM)OMyMyOHellYes Wrote: Does anyone know if HDM has a table like Resmed's that shows the power consumption of their units (in amps) at given pressures?

Um, not to be picky, but power is not measured in Amperes, it is measured in Watts. Watts equals Volts time Amps. So if you know two out of three you can figure out the third.

Ed Seedhouse
VA7SDH

Part cow since February 2018.

Trust your mind less and your brain more.


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#3
RE: HDM Z-1 power consumption?
(02-01-2015, 01:51 PM)eseedhouse Wrote:
(02-01-2015, 09:32 AM)OMyMyOHellYes Wrote: Does anyone know if HDM has a table like Resmed's that shows the power consumption of their units (in amps) at given pressures?
Um, not to be picky, but power is not measured in Amperes, it is measured in Watts. Watts equals Volts time Amps. So if you know two out of three you can figure out the third.


Um, yeah, for these purposes, it is.

electric current: a movement or flow of electrically charged particles, typically measured in amperes.

Given the voltage, 11.7-14.4v for a 12 V storage battery, capacity is shown usually as amp hours.

That's why Resmed Technical Services, when they wrote their battery guide, used current draw in amps for all measurements.

We are looking for the same data for the Z-1.

OMM
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#4
RE: HDM Z-1 power consumption?
Cannot find power consumption V pressure data for the Z1.

The Z1 uses a 45 Watt-hour, 14.4 Volt Li-ION battery. They say one can get 8 hours use from that battery at 14 cm-H2O pressure.
Li-ION chemistry batteries have a fairly constant Voltage during discharge.
At 14.4 Volts, we can convert W-Hr to Amp-Hr.
The battery would be a 3.125 Amp-Hr battery.
For an 8 hour run time, one can infer the running current is 3.125 Amp-Hr/8 Hr = 390 milliAmpere current draw.
(Wow, that's seems incredibly low!)

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#5
RE: HDM Z-1 power consumption?
(02-01-2015, 02:07 PM)OMyMyOHellYes Wrote:
(02-01-2015, 01:51 PM)eseedhouse Wrote: Um, not to be picky, but power is not measured in Amperes, it is measured in Watts. Watts equals Volts time Amps. So if you know two out of three you can figure out the third.


Um, yeah, for these purposes, it is.

Um, no. It's a matter of definition. Power is measure in Watts by definition.

Quote:electric current: a movement or flow of electrically charged particles, typically measured in amperes.

Yes, but current isn't power.

Quote:Given the voltage, 11.7-14.4v for a 12 V storage battery, capacity is shown usually as amp hours.

Sure, but that's not power, that's capacity. Say you have 2000 amp hours at 12 volts. If your rig consumes 90 watts (the rating on the power supply for mine) it will draw (at full power) 90/12 = 7.5 amps and it will take 2000/7.5 = 26+ hours supply those 2000 amp hours.

These are only approximations, of course. Batteries aren't perfect.

Quote:That's why Resmed Technical Services, when they wrote their battery guide, used current draw in amps for all measurements.

We are looking for the same data for the Z-1.


If you know the power rating of the machine you can compute this easily. If your power supply is rated at 120 watts then the current draw is 120/12=10 amps. So to run for 24 hours you'll need a battery that can supply more than 2400 amp hours. Straightforward arithmetic.

If you don't know either the power consumption or the current draw you need to find out at least one since you can probably assume a 12 volt power supply.



Ed Seedhouse
VA7SDH

Part cow since February 2018.

Trust your mind less and your brain more.


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#6
RE: HDM Z-1 power consumption?
VA7SDH
There is an Amateur Radio Thread in Off-Topic.
http://www.apneaboard.com/forums/Thread-...-operators

Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#7
RE: HDM Z-1 power consumption?
(02-02-2015, 03:12 PM)eseedhouse Wrote: If you know the power rating of the machine you can compute this easily. If your power supply is rated at 120 watts then the current draw is 120/12=10 amps. So to run for 24 hours you'll need a battery that can supply more than 2400 amp hours. Straightforward arithmetic.


ROFLMHO

Oh, that too funny!

OMM
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#8
RE: HDM Z-1 power consumption?
(02-01-2015, 09:32 AM)OMyMyOHellYes Wrote: Does anyone know if HDM has a table like Resmed's that shows the power consumption of their units (in amps) at given pressures?

That would be VERY helpful in sizing a battery for more extended emergency usage.

OMM

NO... the HDM does not have a milli amp hour for various pressure ratings chart like ResMed did for the S-9.

On portable pap like the Transcend and Z-1 the manufacturers are pretty good about getting you information on draw and recharge data. Transcend has a solar charging panel as an option.

My experience with Transcend is that at 16 pressure the normal 8 hr battery doesn't cut it. I use the larger 16 hr batter for consistent 8 hours per charge.

In doing any battery supply power option for pap I always like to engineer in extra capacity. I hate waking up when the battery goes dead.

This also assumes any battery pap option you go into it understanding heated humidification on battery is not a realistic option. You need to plan on either pass over humidification or using nasal irrigation.

Hope this helps.
(Just a truck driver with sleep apnea )
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#9
RE: HDM Z-1 power consumption?
I think the standard most knowledgeable members use is a requirement of 150%. Especially since there are probably dozens of variables that go into the equation. IIRC, the ResMed tables used that %'age too.

BTW, this afternoon, I did a quick, informal test on the Respironics 560 w/o humidification. Ran about .32 AH current draw off of an old, but recently charged, 10 AH 12v battery. So I would plan on .5 AH draw. So, for the avg 6 hours a night, I should get a 2-3 nights off that machine with that battery. Granted, most of that nap time was probably nearer the low end of my pressure envelope, so it is probably optimistic and closer to 2 nights max ...

Am eager to see what the Z-1 will do. I would like to be able to get at least that good out of it - that way I would feel good that a 5 AH 12V would get me through a transoceanic flight in either direction absent a power source ont he plane. I am also trying to get a 5 A battery shoehorned into the little case I got for the Z-1
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#10
RE: HDM Z-1 power consumption?
I know this is an old thread but seems like all the info should all be in one place . . . 

I did some measurements with my Z1. None of my test equipment is calibrated or anything. Z1 pressure is set to 13, Z-Breathe at 1. 

Unexpected result that makes sense thinking about it was that the current draw varied with breathing - drawing more current breathing in, drawing less current breathing out. Presumably when you breathe out against the machine, the CPAP doesn't have to push air as hard to keep up the pressure in your airway, and draws less power; when you breathe in, the CPAP has to blow harder to make up for the air you're sucking in, and draws more power. 

Current measurements (at 12.6V were) 

Plugged in but idle: 0.026 - 0.03 amps
On, breathe in:  peak at 1.1 - 1.2 amps
On, breathe out: drop to 0.25 - 0.33 - 0.38 amps
On, no mask, tube open: 1.3 amps
On, no mask, tube blocked:  0.2 amps

So I did this because I was interested in powering the Z1 from a battery that didn't cost $450 and that I could take on a commercial flight. I found a post somewhere where somebody was talking about running it off a USB power bank, into a USB to 12 V adapter like an "ARECORD-Cigarette-Lighter-Socket-Converter" at Amazon, into a 12V Z1 mobile adapter. There are a lot of power banks rated at 5 amp output @ 5V, so the current load should be OK. 8 hours of use @ 1.1 amp is 8800 mAh, so a 16000-20000 mAh pack should be good for at least one night. The USB to 12V adapter is rated at 0.8 amps, which the Z1 would exceed, but not continuously, so that's a potential problem. 

So maybe one of these days I'll get brave and try it.
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