CPAPtalk.com

Physician wrote:

dtsm wrote: Maybe discussed before, but not completely resolved. Thank you for that link, but those Duracell specs (copied below) disclose that the unit is only 480 watts continuous @ $140.

With all due respect it has been resolved...there were at least 4 detail threads from spring 2010 and prior.
There are multiple units/options that work [ or don't work]

1. First, UPS systems don't work for longer than an hour or so. Keep looking if you wish but you're wasting your time, IMHO.

2. You can analyze the Duracell to infinitum...all I can say is 'it works', not just for me for others who have bought the same or similar model[s] for S8 and other ResMed models. Without a humidifier, it will give solid 8 hr backup power. Every couple of months I re-charge it one night and use the second night just to test it, then recharge and put in closet.

3. John's home-made unit also work, others have followed his step by step instructions to build a solid working unit.

after 2 brownouts last week, both for more than 3 hrs, I read through the links given by DTSM. The Amazon link on Duracell 600 provides lots of feedbacks, some very negative.

However so far this seems to be the only option for those who are not technically adept to follow John B Fisher

after 2 brownouts last week, both for more than 3 hrs, I read through the links given by DTSM. The Amazon link on Duracell 600 provides lots of feedbacks, some very negative.

However so far this seems to be the only option for those who are not technically adept to follow John B Fisher

To go the UPS route and replace the batteries realize that almost all UPS's including the ones listed here work off of 24 volts and use two 12Volt batteries in series. So to go that route you would need to purchase 2 Deep cycle batteries. The battery charger built in the UPS's are set up to charge gel cell batteries, they will over charge standard and wet deep cycle batteries.
I did this for my computer supply, I purchased two Deep cycle Marine wet cells, and because of the over charging they only lasted two and half years. Since the warranty ran out I then purchased two 12volt lawn tractor batteries, at $22 each. While much cheaper and not as powerful they only would power my computer system for about 10 hours, they lasted three years until I moved.
For my cpap (M series) which runs off of 12volts I use a wet deep cycle marine 100 amp/hour battery that I put into a battery case and have on a plastic tray underneath my nightstand it is hooked to the cpap with the standard car cable. I use a float charger "Battery Tender Plus" that is designed to automatically keep the battery charged and not overcharge it. I have used this system for the last year, I have 4 to 6 power outages a year, so this is a must for me. With a good smart float charger, and good battery care, battery lifetimes of at least five to six years are to be expected.
Bob

I'm reading this thread and feeling quite dumm, cause I don't think I understand any of it, other than that you guys are looking for an alternative power supply.

Now to post another alternative Aims makes a inverter with a built-in charger and transfer switch, that will auto switch between line power and the inverter, just like a UPS. You just have to add the 12volt battery. The 1500Watt version is on sale for $299 http://www.theinverterstore.com/the-inv ... 0w-top-rgb This is a modified sine wave type that should be good for most cpap's except for the S8. For the purest they do make a deluxe pure sine wave 1500Watt unit for $499 http://www.theinverterstore.com/the-inv ... ric150012s.

Bob

physicsbob wrote:Now to post another alternative Aims makes a inverter with a built-in charger and transfer switch, that will auto switch between line power and the inverter, just like a UPS. You just have to add the 12volt battery. The 1500Watt version is on sale for $299 http://www.theinverterstore.com/the-inv ... 0w-top-rgb This is a modified sine wave type that should be good for most cpap's except for the S8. For the purest they do make a deluxe pure sine wave 1500Watt unit for $499 http://www.theinverterstore.com/the-inv ... ric150012s.

Bob

The modified sine wave should be good enough for the S9. I'm not sure what non-sinusoidal really means but that's what my Vector brand 400 watt inverter says on the label and my S9 ran just fine on it.

I wonder how fast the transfer switch is in the inverter you link to. Which brings up the question, how fast does it have to be to keep the S9, or other PAP, from shutting down? But how much of a concern is that, really?

--I'm thinking that one of the hardware places has something like a power outage alarm.
If I could find one, then it could wake us up sooner than the apnea--
Not quite a UPS, but a way to wake up as quickly as possible in order to manually switch things over.
Definitely not the solution for everyone.

From what I have read as soon as you talk about a Pure sine or true sine wave UPS it states it is a "medical grade" UPS. A pure sine wave inverter, and a marine deep cycle battery is the way to go if you want a extended run time. The key here is you CANNOT use a modified sine wave inverter or UPS. From what I read it will work for a while but some how the square sine waves cause a overheat condition in the circuitry. The modified wave inverters and UPS are cheaper and more popularly priced..

been there and checked it out.

My set up is going in the basement with only a wire up feeding my unit

Swede

Here is my UPS/CPAP solution: (For S9 Autoset consuming 90 watts for 8+ hours of usage)

$150 + $40.02 (shipping) - APC Smart-UPS X 750VA
$349.00 + $29.00 (shipping) - SMX48RMBP2U UPS External Battery Pack - External Battery Pack - 48V DC
$378 + 190.02 = $568.02 (after shipping)

It's probably overkill, but I didn't want a custom/dangerous solution. The above units are 2 rack units each (about 4 inches tall or so) and fit perfectly side by side under my bed. The external battery pack has a cable that goes to the 750VA. I found these on buy.com and ebay. (Be sure to check that the listing says they are new batteries and not used.) I copied this setup from another forum poster on cpaptalk and it seems to work well for a ~$500 solution that is safe and can be reused for other things in the future. I also disabled the alarm on it.

linagee wrote:Here is my UPS/CPAP solution: (For S9 Autoset consuming 90 watts for 8+ hours of usage)

$150 + $40.02 (shipping) - APC Smart-UPS X 750VA
$349.00 + $29.00 (shipping) - SMX48RMBP2U UPS External Battery Pack - External Battery Pack - 48V DC
$378 + 190.02 = $568.02 (after shipping)

It's probably overkill, but I didn't want a custom/dangerous solution.

This is almost exactly the same system I just started using. In my case I've got:
APC Smart-UPS 700XL
(2) SU24XLBP External battery packs.

If I'd only gone with one external battery pack like you did my price would have been about the same. With two I should be able to run my s9 for about 16 hours. Here Its not uncommon to be out of power for 8-10hrs a couple of times a year, and 24hrs maybe once a year, so this didn't seem like such a bad idea. ...and I've got extra to run a night light for the kids who usually freak-out at night during outages, a radio/clock for news, etc.

Instead of dealing on ebay I went with excessups.com They sell UPSs they refurbish themselves, and they sell new ones too. They know what they sell and will suggest a suitable system for you. Since shipping these things makes up a significant part of the purchase price I'd recommend contacting the seller for an accurate shipping quote, not something auto-guesstimated by a web site.

swede wrote:The key here is you CANNOT use a modified sine wave inverter or UPS.

What is your basis for making this statement? Resmed's Battery Guide specifically condones modified sine wave inverters. It has a table for recommended inverter ratings for all the various Resmed units and inverter type. Type includes both modified and pure sine wave inverters.

http://myweb.cableone.net/idahomtnboy/W ... 0guide.pdf

This post talks about what I'm looking for. We had a power outage for three days a couple winters ago. I had a converter I bought from cpap.com for my M-Series Pro. I used it for just the flow generator and used the humidifier in pass-through mode (off). It wasn't as comfortable as warm air, but it was absolutely better than no cpap at all. The problem with the S9 is that without a 12V DC to 90V DC converter, I'm concerned my marine battery wouldn't last three days on a single charge for the S9 because I'd have to first connect an inverter to my battery and then plug the S9 into the inverter. The only thing I can think of to do if I can't get a real converter for the S9 is go back to my M-Series pro during extended power outages. My M-Series could last almost a week on my Marine Battery with its converter. Why shouldn't we be able to have that with the S9?

ResMed - please provide a DC Converter for the S9. It is an absolute necessity.

DreamDiver wrote: The problem with the S9 is that without a 12V DC to 90V DC converter, I'm concerned my marine battery wouldn't last three days on a single charge for the S9 because I'd have to first connect an inverter to my battery and then plug the S9 into the inverter.

I think you mean 12V DC to 24V DC. 90 is the wattage of the power supply.

I can see the concern about overall efficiency of inverter + power supply but I wonder how that compares in reality with the efficiency of a DC-DC inverter. Is there such a significant difference that the DC-DC unit is much more desirable? I have a hard time thinking how the DC-DC could be much more efficient since the same basic steps in the single unit and the combined separate units would have to be much the same. The last I knew the only way to step up voltage is with current passing through a transformer or inductor coil, and that's probably the most inefficient part of the process.

I can't see the problem with Resmed getting the 24 volt converter out, the have a 24 volt version available for vpap. They must be trying to make it exclusive enough so nobody can copy it and keep them from profiting from it. john