Battery Backup Design

[DreamStalker]

John,
Great piece of work.

A related question: I have an S9, which has an external "brick" transformer/inverter. How about just buying a UPS backup like you use for a PC. I am in a part of Florida where power is relatively reliable and most of the outages last less than 15 minutes.

I guess you don't get hurricanes over there like we do here in Texas.

[GumbyCT]

I know Respironics made a DC humidifier. I don't think anyone else has.

[JohnBFisher]

...

... I am in a part of Florida where power is relatively reliable and most of the outages last less than 15 minutes. ...

I guess you don't get hurricanes over there like we do here in Texas. ...

LOL! After living through no power for a couple weeks due to a storm, I decided a large battery every five to eight years was a good investment.

[billbolton]

I know Respironics made a DC humidifier. I don't think anyone else has.

The Resmed H5i, that goes with the new S9s, is DC powered.

Cheers,

Bill

[jmelby]

The Resmed H5i, that goes with the new S9s, is DC powered.

What does this mean in terms of the need to use a full sine wave inverter/UPS?

[johnnygoodman]

Howdy JohnBFisher,

Great work! Have you considered adding it to the CPAP Wiki?

Johnny

[billbolton]

What does this mean in terms of the need to use a full sine wave inverter/UPS?

It means a modified sine wave inverter will be fine for both the S9 and the H5i.

Cheers,

Bill

[GumbyCT]

I know Respironics made a DC humidifier. I don't think anyone else has.

The Resmed H5i, that goes with the new S9s, is DC powered.

Cheers,

Bill

Isn't the poster asking about using a UPS for the blower and humidifier showing an S9 in the equipment profile??

[Zzz_Jim]

The Resmed H5i, that goes with the new S9s, is DC powered.

What does this mean in terms of the need to use a full sine wave inverter/UPS?

I suspect it just means the marketing guys that write the battery FAQ haven't asked the S9 R&D guys about it.

I also suspect the pure sine wave requirement came about from the older AC powered humidifiers, which probably produced audible noise from a modified sine inverter. And they've chosen to just make a blanket recommendation in the FAQ rather than confuse consumer's with different model requirements.

There really shouldn't be any reason why you can't run a Resmed 24VDC out AC adapter powered S9 & humidifier with a modified sine wave inverter. The AC adapter should take care of it. That goes for a Respironics 12VDC out AC adapter also, although Respironics sells a 12VDC cable to hook up to a battery directly, which will be a more efficient way to go for them. I suppose there may be some small chance of over-stressing components in the adapter if it's plugged into a modified sine instead of a pure sine source - but I'd hate to have a switching power supply design that marginal if I was the guy designing it. YMMV, and all that, if you want to try it...

Note that we don't know the tolerance of the S9 24VDC input - it may be that if you try to run it off two 12V lead acid batteries in series that the S9 may not operate correctly at a minimum battery voltage of say 20V (i.e 10V each battery). We should probably wait for Resmed to come out with a 12V battery to 24VDC adapter to operate it portable without an AC inverter, or use an AC inverter to power the AC adapter.

I'm kind of wondering which way to go myself. I'm a newbie currently about 2 weeks into using a PR one Plus. I'd like an S9 instead, but it's harder to run portable. So for portable use I may end up with an out-of-pocket Everest 3, just so I don't have to mess with big batteries when camping. I seem to be doing well with straight CPAP anyway.

- Jim

[GumbyCT]

What does this mean in terms of the need to use a full sine wave inverter/UPS?

It means a modified sine wave inverter will be fine for both the S9 and the H5i.
Cheers,
Bill

To be clear : I do know that most Respironics machines AND one Heated Humidifier model can be powered by 12VDC. I made a DC power cord from Radio Shack parts for about $10. 12V DC is readily available thruout many countries. This makes it much easier during a power outage to get some (sleep).

I have no personal knowledge of how Resmed powers their equipment.

[JohnBFisher]

... Great work! Have you considered adding it to the CPAP Wiki? ...

Why thank you! Flattery works!

Yes, I am working on a Wiki article. I want to make it a bit more detailed (more of the equations and more options) to help others. Unfortunately, due to needing to earn a living and a recent bout with poor sleep, I have not yet completed it.

[billbolton]

although Respironics sells a 12VDC cable to hook up to a battery directly, which will be a more efficient way to go for them.

As advised in another thread, in a few months time Resmed will have available an adapter for the S9 + H5i which allows direct operation (that is, without the mains power pack) off a 12V DC power source.

Cheers,

Bill

[Patrick A]

Wow
Graet job.

[Breathe Jimbo]

My only qualm is the simultaneous use of the Y-connector (1) to recharge the battery and (2) use the battery. Does the Y-connector come with documentation that describes any limitations on the use of both connectors at the same time? Obviously, your long-term use of this design demonstrates safety. However, I'm wondering whether the turning on of the tender while using the battery might cause a surge or cumulative power issue, with the inverter drawing or receiving power from the tender and the battery simultaneously.

Absolutely brilliant design!

[JohnBFisher]

... Does the Y-connector come with documentation that describes any limitations on the use of both connectors at the same time? ... However, I'm wondering whether the turning on of the tender while using the battery might cause a surge or cumulative power issue, with the inverter drawing or receiving power from the tender and the battery simultaneously.

Absolutely brilliant design!

I've not seen any problems with it. But to be honest, I have two different outlets. One that connects me to the outlet only and the other that connects me to the inverter. I tend to stay connected to the outlet only, since that allows me to use the heated humidifier with impunity. But about once a month, I switch it to the inverter to use it for a couple nights. That helps me make certain the battery continues to work and recovers about as expected.

I'm hoping to finish putting together a Wiki article in this upcoming year. Unfortunately, due to dealing with insurance, my life has been "interesting" this past year, so that project remains on my "To Do" list.

Thanks for the note about the design. I find it works well. I've seen no problem with the battery or long term usage.