multi day battery operation

[Krelvin]

Just leaving the machine plugged in to the UPS while the humidifier gets plugged into the wall would defeat the reason I started using the UPS in the first place since passover humidification just isn't enough for me.

If all you have are short power failures, leaving the humidifier plugged into the wall most likely won't have much of an effect to the amount of humidity it puts out for the short duration that it is off. It would have to be off for more than a couple minutes before the effects of the humidification would start to drop.

A longer power failure would have an effect but then you most likely would be waking up anyway. At least around there you would, due to the heat during the summer. No air doesn't stay comfortable for long.

Its 11:18pm now and its still 92F outside.

[Sleepy-in-AL]

Just leaving the machine plugged in to the UPS while the humidifier gets plugged into the wall would defeat the reason I started using the UPS in the first place since passover humidification just isn't enough for me. I know that the humidifier would only run for a very short amount of time (maybe a couple of minutes?) before the UPS power would run out. Could serious damage be done in that short period?

OK, I did another test after I had been running for several hours. On the BiPAP Auto at least, if the power is removed from the humidifier for short periods of time it will come back on when thse power is reapplied. I think I pulled the power for about 1 minute or so. So, as Krelvin suggested, during a short power outage the residual heat should carry over and then the heater should kick in again when power comes back on.

If you really need to have constant heat, look for a UPS that has "true sinewave" output. It should say so on the box. Also, look for a really big one. As far as the damage resulting from short periods of use, I'm not sure. As I said before, I haven't looked closely at what the failure mode is or what causes the failure. YMMV

[BATPOO]

For camping I use a PB 420, no HH, connected directly to a 36 AH, 12v sealed AGM battery. The CPAP draws 0.7 amps at a setting of 12 cm H2O. The battery weighs 28 pounds. I easily get 5 nights out of this setup.

Some helpful (?) notes:
* Inverters are not terrably efficient so you will get the most power for the weight by using a 12v CPAP connected directly to a battery. The cost of a 12v CPAP and small battery may be comparable to that of an expensive inverter with large battery setup.

* Batteries: Use "deep cycle" AGM batteries. They are rugged and are orientation insensitive. The Optima brand batteries are, in my opinion, overpriced. There are generic AGM batteries out there that cost 1/2 of what the Optimas do.

[roster]

Here is a good source of information on batteries:

http://www.windsun.com/Batteries/Batter ... lectrolyte.

Have a look at the AGM batteries description.

[Sleepy-in-AL]

OK, did a little searching and now it makes sense. Here is a quote from http://www.newtechpub.com/sleep/magazin ... wer03.html. Take a look at the article for more information on using batteries for xPAP power.

WARNING: Do not use an inverter power source to run a heated humidifier.
Technical explanation, adapted from information supplied by Shane Finn at ResMed: Humidfiers use a triac or thyristor to regulate the power by turning on partway through each mains cycle. The controller assumes the mains voltage is sinusoidal. However, inverters generally do not provide a true sinusoidal output, thus the controllers make wrong decisions and cause the humidfier to deliver full power continuously, and may burn out the heating element. Another, more intelligent type of controller is termed an integral cycle controller or burst controller, and would provide full power in short bursts. However, we know of no heated humidifier using this type of controller.

I'm not sure how long it would take to damage the heating element, but it wouldn't take an extremely long time.

[jondough]

A great ResMed article that answers most questions on DC operation.

http://resmed.com/Shared/StaticFiles/-n ... ts-usa.pdf

For my trip, I had sort of decided to forgo trying to use my 24VDC BiPapPro2 and rent a 12VDC bilevel machine for the two weeks. My DME did not have the PB425 so I called ResMed about the VPAPIII. That is how I got the link. But the III does not have any DC input so you have to use an inverter which uses up some power. There is a new VPAPIIIA which does have a DC input BUT it is also 24VDC. So it seems like the only bi-level direct 12VDC machine is the PB425.

Back to research. Anyone have a good price source for the Honda generators? Or a suggeston for a similar nice package that is not so price protected?

Thanks to everyone for all the suggestions. Great discussion, too bad it is on so many threads. RG can you pull them all together somehow?

[Sleepy-in-AL]

A couple of references for those following along:

Please note I am not in any way connected with Harbor Freight, I just know they have cheap tools that are usually pretty good compare to some of the junk we see.

For an inverter, they have a 400W continuous/800W Peak on sale for $24.99. See http://www.harborfreight.com/cpi/ctaf/d ... mber=92708

They also have a 150W continuous/450 Watt Peak on sale for $19.99.
See http://www.harborfreight.com/cpi/ctaf/d ... mber=93095


For a small compact generator, they have a Chicago Electric (Store Brand I think) 1000W / 8A @ 120V / 10A @ 12V (power, not charge) 2.4 HP on sale for $299.
See http://www.harborfreight.com/cpi/ctaf/d ... mber=93881

Hope this helps.

[Nitro Dan]

For power outages, I have a Honda EB 11000 watt gen set. When the power goes out, I crank it up and throw the transfer switch, and the whole house is energized and it runs the CPAP and humidifier with no issues. When I'm RVing, I use the Honda EU 3000 gen set. Because it is the inverter type generator, I just use my passover humidifier and not my heated one. When I'm dry camping, I use 2 six volt golf cart batteries, wired in series to get 12 volts, then use an inverter to get the AC for the CPAP, (12 volt to CPAP will not get me the pressure I need) and use my passover humidifier. The batteries will last me at least a week on a single charge. (be sure to unplug inverter during times of no CPAP use or it can drain your batteries)

[cwsanfor]

I have a APS BackUPS XL 800, and I was going to plug my Remstar Auto into the UPS-protected outlets, and the Heated humidifier into the surge-only-protected outlets on the XL 800. The effect would be that the Remstar Auto was on a UPS, and the heated humidifier was on a surge suppressor.

Any problem with sine waves and thyristors using this approach?

Thanks.