What Battery Back up System do you use ? Post Pics

[OMyMyOHellYes]

ResMed makes a 12V to 24 V converter designed for their units. Other manufacturers likely do the same.

Mongo.

I don't think so. Most of the CPAP units I've seen were 12V, with the exception of the ResMed S9, and would not require a voltage converter. BUT I've not seen them all....

My DeVilbiss runs great off direct 12V battery. The S8 was 12V and would run off direct battery (which as you say is variable - they run about 13.5-14V at full fresh charge down to about 11-11.5V which is when I would swap them out) but the S8 coax plug socket was reverse wired - IMPORTANT POINT (probably to be different and make folks buy their wire, I'm guessing.)

OMM

[herbm]

Tripp Lite SMART1500LCDT 1500VA 900W UPS Smart LCD Battery Back Up Tower AVR 120V USB
[link removed]

I already had two of these:

1) Big screen TV and multimedia PC, U-verse receiver/DVR, plus living room networking gear

2) My two Virtual Machine (VMWare and Hyper-V) host servers (these servers hold multiple "virtual computers" each)

Each of these were running at about 1/3 capacity which led me to believe it would give me plenty of time for the CPAP. The metering suggests several hours (or more) is possible, but we haven't had a significan power outage since this arrived.

I had intended to just unplug it and test it one night but then my hip started hurting leading to terrible sleep and eventually the hip replacement last week so that hasn't been a priority.

Maybe tonight I will do that (since I don't have to work tomorrow for Labor Day and my hip is doing wonderfully.)

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[APAAW]

Sorry, this is the cheaper version of the Tripp-Lite that _doesn't_ have an oxygen adapter.

Seriously, though, this is another good answer to the thread I was wondering about a couple of days ago: http://www.apneaboard.com/forums/Thread-...-Post-Pics

A comment at Am*zon _quoting_Tripp-Lite_ says that on battery it doesn't generate pure sine waves: "The AC output waveform for the SMART1500LCDT in battery mode is a modified, or pulse width modulated (PWM) sine wave" and " It will not be compatible with PCs that have power supplies that require pure sine waves at all times". Ouch.

But in general: why wouldn't it work to attach an outboard 12v lead-acid battery of higher watt-hour capacity in parallel to give a UPS much longer run-time for a CPAP with a peak requirement of 60 - 80 watts? I'm "assuming" that if a particular UPS can handle supplying hundreds of watts for 90 minutes, it could handle 1/10th the workload for 5 times the time. But I'm not a EE. In fact, I'm not most things...

It might be desirable (or mandatory) to disconnect the external battery to recharge it separately, but it still seems like it would provide power regulation and several days' CPAP run-time at comparatively low cost, at least for those living where power almost never goes off for more than a few minutes at a time. (BTW, does anyone have any deeper background on the failure of "voltage suppressors" during the recent Napa earthquake?)

[justMongo]

I think you could use an external lead-acid AGM or gel battery of high Amp-Hr capacity.
Start with it fully charged, the UPS can keep it charged until it switches to battery.

You might need two 12V batteries. My UPS has a 24 Volt pack in it.