UPS - uninterrupted power source

[dtsm]

Curious how many folks have a UPS backup? Did a search but most of the threads dated 2006: search.php?keywords=%22UPS+backups%22. Any recent updates, etc....

And if so, what would they recommend for ResMed S8 AutoElite II model (w/out humidifier running)?

[Paul56]

Curious how many folks have a UPS backup? Did a search but most of the threads dated 2006: search.php?keywords=%22UPS+backups%22. Any recent updates, etc....

And if so, what would they recommend for ResMed S8 AutoElite II model (w/out humidifier running)?

I have one for the computer equipment downstairs here... almost essential for me with working at home.

I don't have one on the apnea machine. If you get one for the ResMed ensure that it has pure sine wave output because if you use anything will burnout the humidifier.

[Madalot]

I was wondering about this myself, after spending both Friday and Saturday nights without power after a severe ice storm. I HATE being without my bipap and oxygen, but we just didn't have what we needed to run them.

[reitzell]

I live in San Diego California. The power outages we have tend to be rare and brief. In my pre-CPAP life my only clue that the power had gone out was the fact that digital clocks were blinking 12:00 when I woke up.

My goal was/is to remain blissfully unaware that the power has gone out. I had an old Belkin 550VA UPS. It had an alarm when the power went out that I could not silence with settings/software so I pulled the peizo noise component off the circuit board.

I got a 55AH deep cycle AGM battery that I keep in a battery box and I wired it to my UPS.

I have a Respironics CPAP M plus with integrated heated humidifier. I got the exact model number and looked it up on the manufactures website and the model I have specifically states that it is OK to run it off an inverter.

The UPS has plugs that provide backup power and it has plugs that only offer surge protection. I have a heated hose that is plugged into a surge suppression plug because I’m not sure it is OK to run it off an inverter and I plug the CPAP into the backup power.

I haven’t had a power outage yet but I’ve “tested” it for four hours and it ran fine.

There is an Internet show called “systm” (I did not misspell that) You can google for it. They have an episode on hacking a UPS.

I coppied this from another post because I'm lazy.

I run the heated humidifier and CPAP off an inverter with no problems. As stated above the manufacture specifically states this is OK. I've measured how many amps this pulls when running through the inverter and it is 5 amps. Then I got the DC cable and connect it to the battery (circumventing the inverter) and measured amps and it pulls .98. So, now if the power goes out a little light kicks on and so I have some indication that power has gone out. If I notice this I just switch to direct DC power. Also, I added the power has failed alarm to the backup power source if it were to go out.

Over thinking this problem is a lot of fun.

I have a friend who I am setting this up for who also has the same CPAP machine I do.

Good luck. Lots of posts on this.

Rob

[fadedgirl]

I live in San Diego California.

I have a friend who I am setting this up for who also has the same CPAP machine I do.

Hey Rob, I'm in San Diego too, how much do you charge?

Seriously though, what is the benefit to this vs. the battery packs that Respironics sells, aside from surge protection? Longer usage time?

[timbalionguy]

I run the heated humidifier and CPAP off an inverter with no problems. As stated above the manufacture specifically states this is OK. I've measured how many amps this pulls when running through the inverter and it is 5 amps. Then I got the DC cable and connect it to the battery (circumventing the inverter) and measured amps and it pulls .98. So, now if the power goes out a little light kicks on and so I have some indication that power has gone out. If I notice this I just switch to direct DC power. Also, I added the power has failed alarm to the backup power source if it were to go out.

Rob

A good battery and inverter will get you better service than a UPS. Especially if power outages are long and/or frequent. But it will not auto-switch to DC unless you want to float-charge your battery (another whole topic!).

The experience above illustrates why directly powering your machine from DC is better if you do not need the humidifier. The machine and humidifier are drawing 5 amps (I am assuming measured on the battery side of the inverter), which is about 60 watts of power. To get one nights' service, you would need a battery with a capacity of at least 40 Ampere-hours, and you would realistically want 60 or 80. Running direct DC without the humidifier uses about 12 watts. An 8 AH battery would power this machine for a night, and a 20 AH battery would be a good choice. A 20 AH battery is much smaller (and lighter) than an 80 AH battery!

Besides the extra load from the heaters, you have conversion losses in the inverter and in the machine's AC power supply. You also have losses due to 'power factor', which is an issue with some machines. Power factor problems also explain why some UPS'es may not like a CPAP machine as a load.

I will also emphasize the importance of using a 'pure sine wave' inverter with ResMed machines. Unfortunately, these inverters (or UPS'es) are heavier, less efficient and cost more.

I just got a ResMed machine myself, so I am looking at the same issues. Unlike the IntelliPAP I previously used, you cannot simultaneously power this machine from AC and DC.

Considering the number of people here that want battery backup with a humidifier, I think I might work out a practical float charging scheme that people here can adopt without having to be a total 'geek'.

[reitzell]

I live in San Diego California.

I have a friend who I am setting this up for who also has the same CPAP machine I do.

Hey Rob, I'm in San Diego too, how much do you charge?

Seriously though, what is the benefit to this vs. the battery packs that Respironics sells, aside from surge protection? Longer usage time?

The idea is if I am asleep I don’t want to get up and switch to another battery because the power has gone out.

If I’m awake and the power is out I’ll switch to DC cable that is already there.

In my case I had an unused UPS and I just had to get the battery. Also, make sure you get a battery that doesn't vent. This battery doesn't under the correct conditions.

I'd be happy to help you get this together. I am not an EE. I just read all of the info here and elsewhere about it.

Rob

ETA (Edited To Add) : Now that I think about it....I flunked out of my DC/AC circuit analysis class.

[reitzell]

I run the heated humidifier and CPAP off an inverter with no problems. As stated above the manufacture specifically states this is OK. I've measured how many amps this pulls when running through the inverter and it is 5 amps. Then I got the DC cable and connect it to the battery (circumventing the inverter) and measured amps and it pulls .98. So, now if the power goes out a little light kicks on and so I have some indication that power has gone out. If I notice this I just switch to direct DC power. Also, I added the power has failed alarm to the backup power source if it were to go out.

Rob

A good battery and inverter will get you better service than a UPS. Especially if power outages are long and/or frequent. But it will not auto-switch to DC unless you want to float-charge your battery (another whole topic!).

The experience above illustrates why directly powering your machine from DC is better if you do not need the humidifier. The machine and humidifier are drawing 5 amps (I am assuming measured on the battery side of the inverter), which is about 60 watts of power. To get one nights' service, you would need a battery with a capacity of at least 40 Ampere-hours, and you would realistically want 60 or 80. Running direct DC without the humidifier uses about 12 watts. An 8 AH battery would power this machine for a night, and a 20 AH battery would be a good choice. A 20 AH battery is much smaller (and lighter) than an 80 AH battery!

Besides the extra load from the heaters, you have conversion losses in the inverter and in the machine's AC power supply. You also have losses due to 'power factor', which is an issue with some machines. Power factor problems also explain why some UPS'es may not like a CPAP machine as a load.

I will also emphasize the importance of using a 'pure sine wave' inverter with ResMed machines. Unfortunately, these inverters (or UPS'es) are heavier, less efficient and cost more.

I just got a ResMed machine myself, so I am looking at the same issues. Unlike the IntelliPAP I previously used, you cannot simultaneously power this machine from AC and DC.

Considering the number of people here that want battery backup with a humidifier, I think I might work out a practical float charging scheme that people here can adopt without having to be a total 'geek'.

Yes. "...measured on the battery side of the inverter"

Considering the number of people here that want battery backup with a humidifier, I think I might work out a practical float charging scheme that people here can adopt without having to be a total 'geek'.

Very interested in this myself.

Thanks,
Rob

[JohnBFisher]

... Considering the number of people here that want battery backup with a humidifier, I think I might work out a practical float charging scheme that people here can adopt without having to be a total 'geek'. ...

Actually, I just built one for which I will post the information. I decided I wanted a decent battery backup in my bedroom, but wanted it to be maintenance free and REALLY easy to plug in and forget (if I wanted to do that). I will probably post it (example part numbers, pictures and such) under a new post. Includes a way to modularize the battery and the output. Costs a bit more, but it has less chance of having problems.

The good news is that with a pure sine wave inverter a user could drive their humidifier if they want. Not sure the hours it would last, but it's a simple, modular approach. KISS always seems to be the best approah.

[torontoCPAPguy]

I use an APC Backups 1000 which will give me the 12 watts that the ResMed S8 Autoset II consumes on its own for almost ten hours. I have it set to alarm after a total power failure only so that I can wake up, reset the UPS and turn the humidifier off (the humidifier consumes too much juice for any reasonable UPS to handle, something like 500 watts). The UPS, if you are prepared to leave the humidifier off or not have one, can just be left with the alarm off in which case you will likely wake up not even knowing that there was a power failure.

Now I need to go and make sure that my APC Backups 1000 is producing a pure sine wave; I have a feeling it is not as there are very very few UPS' that produce a pure sine wave output. Close, but not pure.

I figured that if it was good enough for all the other delicate electronics in the house and office it would be okay for the Autoset II. Comments?

[JohnBFisher]

... I figured that if it was good enough for all the other delicate electronics in the house and office it would be okay for the Autoset II. Comments? ...

For the autoset, definitely. For the humidifer, as you note, nope. But the alarm on that thing is annoying enough to wake most anyone. My dog hates it when my APC UPS kicks in.

[pb5927317]

http://www.tigerdirect.com/applications ... &CatId=234

Check out the cyberpower units...more reasonable then the APC, and I have had very good luck with them.

Actually, they have protected against lighting when the APC units have not.

[Pirateghost]

Check this out from Xantrax. It lasted me all night w/humidifier running.

http://www.amazon.com/gp/product/B000E6LEI2

[torontoCPAPguy]

[quote="Pirateghost"]Check this out from Xantrax. It lasted me all night w/humidifier running.

http://www.amazon.com/gp/product/B000E6LEI2[/quote]

This is a 400 watt unit. Does your humidifier heat the water? I am sure it is the heater in the ResMed that draws 500 watts. A 400AH unit would never power the CPAP with the humidifier on for very long.

[timbalionguy]

Check this out from Xantrax. It lasted me all night w/humidifier running.

http://www.amazon.com/gp/product/B000E6LEI2

This is a 400 watt unit. Does your humidifier heat the water? I am sure it is the heater in the ResMed that draws 500 watts. A 400AH unit would never power the CPAP with the humidifier on for very long.

The heater in the ResMed unit does not draw anywhere close to 500 watts. However, I suspect that it uses a power control system similar to an AC lamp dimmer, which does require a sinusodal power waveform to function properly. I do not know where they are getting the high 'instantaneous peak power' figure from in their literature. The heater is a simple resistance heater that probably doesn't use more than 100 watts run wide open. Where the trouble is, is that the power is used during only part of the AC waveform, which may be looking like a load with a 'power factor' problem to the UPS. Power factor can cause things like UPS's to use a lot more power than they are really producing. Without getting into a complex explanation of what power factor is, it is kind of like having a CB antenna with high SWR, if you remember those.