Battery capacity planning: estimating pressure?

[dh37]

I have a ResMed Airsense 10 Autoset. I'm setting up an off-grid power setup so I can use my machine while camping. I already ordered the ResMed converter, and will probably get an AGM lead acid deep cycle battery as well as a battery tender.

I'm unsure what pressure to use to estimate what battery capacity I need. When the machine starts up, it says 5 - 15; the actual pressure used is auto. I don't see pressure displayed in the sleep report.

I could use 15 as an upper bound; or, I could try to set up the (Oscar?) software to read a typical pressure off an SD card. I know that's more a matter of judgement, but what do people think?

Also, if the battery were to happen to run out of charge in the middle of the night (for whatever reason), would it damage my machine, or would the converter be smart enough to shut off?

[Dog Slobber]

Here's the ResMed battery guide to help you determine draw:

https://document.resmed.com/documents/a ... lo_eng.pdf

Download OSCAR, one of the values it displays is average pressure. Under Statistics,, you can see month-by-month or last week, 30 days, 6 months or year.

By the way, an auto set to 5-15, is almost always non-optimal. You may want to post some graphs and target you pressure a little closer to your needs. This could improve your therapy and give you a more consistent pressure for estimating battery draw.

There is no "graceful" shutdown of the machine when the battery runs out. It's just like unplugging it. Don't think it will harm the machine.

[dh37]

By the way, an auto set to 5-15, is almost always non-optimal. You may want to post some graphs and target you pressure a little closer to your needs.

Huh. Didn't know that. Isn't the machine supposed to be able to figure out what the pressure should be?

[loggerhead12]

Huh. Didn't know that. Isn't the machine supposed to be able to figure out what the pressure should be?

It raises the pressure when it senses events, then drops it back down to the minimum. 5 is too low for a lot of people.

[loggerhead12]

If you want to get more precise, order one of these guys and wire it inline.

https://www.amazon.com/gp/product/B013P ... UTF8&psc=1

Then you can do this:

[Dog Slobber]

By the way, an auto set to 5-15, is almost always non-optimal. You may want to post some graphs and target you pressure a little closer to your needs.

Huh. Didn't know that. Isn't the machine supposed to be able to figure out what the pressure should be?

No.

And there isn't a pressure our machines should *always* be at.

When you're sleeping on your back your pressure needs are probably different than when you're on your side; when you're in REM your pressure needs are different than when you're in non-REM; when you've had a half-dozen beers your pressure needs are different than when you haven't had a drink in a week.

Your machine increases the pressure according to its measured key-point-indicators. It always wants to return to its minimum value (5 for you) then when it measures somethings that suggests it increase its pressure, it may have a long way to go to get there. By the time it does, your airway may have collapsed, it now needs to use more pressure to open it, then it would to have simply kept it open.

[dh37]

Thanks, guys. Very helpful.

[dh37]

If you want to get more precise, order one of these guys and wire it inline.

Can I use that while using my machine hooked up to AC power? I assume that the power brick is an AC adaptor that converts AC to DC, and I'd stick this meter between that and the machine.

[loggerhead12]

Can I use that while using my machine hooked up to AC power? I assume that the power brick is an AC adaptor that converts AC to DC, and I'd stick this meter between that and the machine.

Not that one. It's DC-only and 100V max.

You really want to measure the current going into the DC converter from the battery. That's the load the battery will see.