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bayareacpap wrote:

The Phillips Respironics 560 units are similar in functionality to your S9 and they don't require a converter.

Thanks for the info Sleep_Quest! I will check out how much power this option will save me.

No problem...CapnLoki has battery usage info on the 560 in one of his threads: viewtopic.php?t=102179 It's very helpful.

Whereabouts are you? That would determine which member is closer to you if you are interested in purchasing a used low hour 560 unit.

Capnloki - from your old post that Sleep Quest posted above, it looks like you used about 20AH (roughly) using the humidifier with your Respironics at a pressure of 9. The Resmed battery document says that the S9 would also use 20AH at pressure of 9 with humidifier (I use 9 also). Do you have a sense of how much of a difference there is between Respironics and Resmed in terms of battery usage with and without the humidifier (trying to figure out if Resmed document is realistic vs your real world tests)? Just trying to figure out the power savings if I switched to Respironics to see if it is worth it.

I would get a PR system anyway and bring your Resmed. You will want to have a back system in case of problems. That way you can leave the resmed at home and use the PR system as a travel one. Keep it always packed and ready to go and you won't forget a component.

bayareacpap wrote:Capnloki - from your old post that Sleep Quest posted above, it looks like you used about 20AH (roughly) using the humidifier with your Respironics at a pressure of 9. The Resmed battery document says that the S9 would also use 20AH at pressure of 9 with humidifier (I use 9 also). Do you have a sense of how much of a difference there is between Respironics and Resmed in terms of battery usage with and without the humidifier (trying to figure out if Resmed document is realistic vs your real world tests)? Just trying to figure out the power savings if I switched to Respironics to see if it is worth it.

I've always assumed that the Respironics, without humidity, is around 10-15% more efficient due to the voltage conversion. I really don't know about humidifier efficiency, because on the newer machines are greatly affected by sensing the ambient humidity and the fact that it comes down to subjective judgement. The heater itself is simply a matter of BTUs in/vapor out so there's probably just a small cost in the 12 to 24 V conversion. Heated hoses are clearly a large burden.

I'm happy I started with the PRS1 560 (through no fault of my own) and bought a second for backup/travel but efficiency cost of the Resmed wouldn't be enough to make me toss it. As a second machine, the 560 is appealing.

When running straight CPAP (no auto), I'm at 12 inches H2O. As mentioned by others, one of the reasons I kept my old ResMed S8 was that it runs off 12v DC instead of the 24V for newer ResMed machines. In the US of A, I use a Respironics PRS1 Auto, which also runs off 12v DC. I have not taken it abroad, because I feared damaging it in dusty locations with dirty power. I did get the 12v cord for it, which is a simple cord, as opposed to the expensive and bulky adapter for the ResMed S8 (and 24v S9).

I live in a 3rd world country and I just recently got a Resmed S9. We put surge protectors on just about everything because of the power fluctuations. We have had TV sets that keep shutting off because of voltage issues. So far, I have not had any problems with my S9. I live in Panama.

Thanks for all of the great information, ALF, PEF, and CapnLoki!

Capn Loki

Can I ask a couple of follow up questions about chargers for deep cell batteries? I am looking at a Schumacher charger because it is the only one I can find that has an input of 240V (needed for where I am going).

1. Is it hard on a deep cell battery to constantly charge it with a higher amp charger in one afternoon (maybe 15 amp or something) vs. using a trickle charger?
2. Do you have a sense of what would happen in a brown out situation if you were charging a battery (like if power voltage from 120v to 80v or something)? Would it just stop charging or would it catch fire etc?
3. if I use a different brand, I would need to use an inverter to charge voltage from 240 to 120. Do you think this would be a decent solution or would it cause too many issues (I am concerned about too many failure points with so many components since it will be difficult to replace where I am going)?

bayareacpap wrote: Can I ask a couple of follow up questions about chargers for deep cell batteries? I am looking at a Schumacher charger because it is the only one I can find that has an input of 240V (needed for where I am going).

1. Is it hard on a deep cell battery to constantly charge it with a higher amp charger in one afternoon (maybe 15 amp or something) vs. using a trickle charger?

The battery will only accept what it wants to. Just because the charger is "15 Amp" that does not mean the battery will accept that. There's a whole science devoted to acceptance rates, which are usually stated as current versus voltage, while at certain charge states. When a battery is near full charge, it needs a proper "float charge" which is about 13.2 volts. Too high or too low will reduce battery life. Most quality charges will automatically go to this, but for real long term float charging I prefer something like the BatteryTender which is designed specifically to do this over a long period.

bayareacpap wrote:2. Do you have a sense of what would happen in a brown out situation if you were charging a battery (like if power voltage from 120v to 80v or something)? Would it just stop charging or would it catch fire etc?

I don't normally encounter brownouts so I really don't know. 12V systems usually shutdown on "undervoltage" situations.

bayareacpap wrote:3. if I use a different brand, I would need to use an inverter to charge voltage from 240 to 120. Do you think this would be a decent solution or would it cause too many issues (I am concerned about too many failure points with so many components since it will be difficult to replace where I am going)?

I'm not sure what you mean. It should be possible to find chargers that accept both 120 and 240 volts - Shumacher and BatteryTender sell these, and I assume most "name brands" also would. Frankly, I would be calling manufacturers and asking if they have a distributor or other presence in your target country.