Recommendation please: Battery for ResMed S9

Has anyone used the ResMed RPS II battery? If so, what is your feedback? I want to use it with my S9 for travel, sailing and camping applications. Are there any better options users can suggest?

Thanks for any information,

Roger

RocketRog wrote:Has anyone used the ResMed RPS II battery?

Ooooooh, nice find.

I suspect its too new as a product for anyone to have tried it as yet!?!

Cheers,

Bill

I asked ResMed France about a battery for an S8 or S0 and was told (and I quote from their rep) ResMed ne commercialise lui-même de produit pour répondre à votre besoin. which means ResMed do not themselves commercialise a product that would meet your needs ... I'd asked for a battery that could do a full night's duty (8 hours min) for a CPAP operating at 14 cmH2O.

However, he did mention this one for an S8 and in a further email said it would suit an S9

https://www.cpap.com/cpap-machine/cpap- ... cable.html

Hope that helps a bit!

ResMed RPS II battery

I agree BillBolton - Indeed, that IS a nice find! However, it does not appear to be too new of a product, as a recall was issued in August of 2010 for some defective units: http://www.bfarm.de/cae/servlet/content ... oad_en.pdf

Too bad it's (apparently) not available in the U.S. And now after having that little scare, it seems less likely that ResMed will make it available in the overly litigious U.S. Too bad

ignorant1 wrote:it does not appear to be too new of a product, as a recall was issued in August of 2010 for some defective units

Well, that wasn't for an RPS II battery system

The Resmed Power Station (with no II) appears to be a product that has been previously been marketed primarily to the "ventilation" market rather than the "xPAP" market. It is in the "ventilation" marketing collateral (http://www.resmed.com/au/assets/documen ... ow_eng.pdf) and was available in a US version.

The illustration in the RPS II user guide shows an S9 style device connected directly to the RPS II, so its seems like the RPS II is being aimed at both the "ventilation" and "xPAP" markets.

Cheers,

Bill

I apologize for the erroneous information; I didn't recognize that the recall was for an earlier system. Mea Culpa.

I do hope that ResMed makes it available to the U.S. market, and hopefully at a competitive price.

P.S. - I didn't see anywhere in the literature if they give any indication of the capacity, i.e., amp-hour rating. Or am I just being blind or stupid again?

I've sent the details of this to the local French ResMed rep ... he's going to be sick of me very soon if not already, to see if I could get any information about availability. I do wish the information - albeit confusing - was reasonably accurate as to availability and existence!

ignorant1 wrote:P.S. - I didn't see anywhere in the literature if they give any indication of the capacity, i.e., amp-hour rating

There's a Watt Hour rating in the on-line User Guide, which is just another way of stating the capacity.....

• Capacity < 100 Wh (97 Wh)

You can work out the Amp Hour capacity from the Watt Hour capacity using basic electrical relationship calculations, if you need to.

Cheers,

Bill

I use http://www.bestcpapprice.com/Compact-Po ... p_516.html and http://www.amazon.com/Cobra-CPI-150-Mic ... B000F6NULK .
I have a Resmed S9 auto set to 11-14 cm. I tested it for 1 night and used 1/4 of the battery capacity with the humidifier off. This unit should last at least 3 nights on a charge.

RocketRog wrote:Has anyone used the ResMed RPS II battery? If so, what is your feedback? I want to use it with my S9 for travel, sailing and camping applications. Are there any better options users can suggest?

Thanks for any information,

Roger

Well, I'm responding to my own post after buying and using the ResMed RPS II battery. Under 1kg, easy to use, 97 watt/hours (enough for 2 x 7 hour sleeps, no humidifier). Larger capacity batteries (over 100 watt/hours) are not officially permitted on aircraft, so this is it for me. Have used it while on sailing trips, overnight flights and train travel, camping and all is good. I keep it fully charged in case of a power outage. Expensive for what it is at A$520, but liberating.

Roger

Upgraded from an S8 to an S9 with the resmend 90W 12V supply so I could run the humidifier on a boat but have come across a problem!

The battery bank is about 300AH but is about 60 ft away from the 12v socket. When I start the S9 with the humidifier it starts up then almost immediately suts down and reboots - I suspect that the voltage drop is too great.

If I replace the climate control hose with a standard one and set the humidity to 0 then the machine works perfectly all night, as did the S8 before.

It is a shared ownership boat so I cannot make any permanent changes to the wiring.

I was thinking of putting a small 12V UPS battery, 7AH or so, near the S9 supply to smooth out the voltage. This would be connected to the 12V socket so I hope that once up and running the average load can be maintained by the boat wiring.

An thoughts on if this would this work?

I suspect the boat wiring is not carrying enuff current to keep the machine alive.

blanik wrote:I was thinking of putting a small 12V UPS battery, 7AH or so, near the S9 supply to smooth out the voltage. This would be connected to the 12V socket so I hope that once up and running the average load can be maintained by the boat wiring.

How is it this won't be a permanent change? IF I were going thru this much troubles I would just bring a jump starter or another battery capable of lasting the nite.

viewtopic.php?f=1&t=64943&p=702353&hili ... on#p702353

I don't think current is the issue...

Assuming 12 AWG wire and an 8 amp draw, the voltage drop over 120' of wire (60 x 2) is a little over 3 volts. There may also be some additional resistance in the various connections. That means that your machine is expecting 12 volts but only getting 9. By removing the humidifier and heated hose you drop the current draw about in half and the voltage drop is also reduced about in half. Now the machine is expecting 12 volts and getting 10.5. Close enough to run.

Several solutions come to mind...

Sleep closer to the battery pack.
Hook the machine up to the battery pack and run a long hose to your quarters.
Use an inverter hooked up at the battery pack to step the voltage up to 120 volts, then use an extension chord to your machine.

The third option is probably the best. Adding a remote battery at the 12 volt outlet will only work for a short while until the remote batteries voltage drops to the value of the voltage drop voltage of the main battery pack.

The other option that has been mentioned is to set yourself up with a remote stand alone battery pack and charge it off of the main battery pack during the day. You would only need to size the battery for 1 nights use as long as you could charge each day.

HoseCrusher wrote:I don't think current is the issue...

Assuming 12 AWG wire and an 8 amp draw, the voltage drop over 120' of wire (60 x 2) is a little over 3 volts. There may also be some additional resistance in the various connections. That means that your machine is expecting 12 volts but only getting 9. By removing the humidifier and heated hose you drop the current draw about in half and the voltage drop is also reduced about in half. Now the machine is expecting 12 volts and getting 10.5. Close enough to run.

I would not expect any cpap (or other device) designed to work on 12v to even show a display at 10.5VDC much less at 9V.

That fact that the OP says the machine initially powers up tells me it is in fact getting adequate voltage and current.

blanik wrote:The battery bank is about 300AH but is about 60 ft away from the 12v socket. When I start the S9 with the humidifier it starts up then almost immediately suts down and reboots - I suspect that the voltage drop is too great.

If I replace the climate control hose with a standard one and set the humidity to 0 then the machine works perfectly all night, as did the S8 before.

Adding the humidifier is either drawing too much for the battery or the wires are limiting the current. Don't forget we have NO idea IF there are splice connections or what the gauge wire is.

Can we find out what this wire was originally installed to service? Is the DC adapter homemade?

The only assumption I would make is that the battery is adequately charged. IF it is not - ALL bets are OFF!!!

You would be surprised what 12 devices actually run on... In addition we don't know if there is something like an AVC in the circuit.

http://www.12volt.com.au

Notice that it supplies power for 60 seconds, then cuts the power if the voltage drops below the set point.

The figures I gave are theoretical and a reasonable guess. The only way to verify what is going on is to measure the voltage. That data will help define the problem.