Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

DC for Resmed S8
#1
I'm looking at a Resmed S8 as a camping Cpap to runoff a deep cycle battery. I found a little used S9 but Resmed does not support the unit any more and I haven't been able to find a Resmed DC power connection kit anywhere online. Does any one here have any suggestions?

Thanks
Post Reply Post Reply
#2
Supplier #1 sells the ridiculously overpriced ResMed DC converters for S8, S8 VPAP, S9, and A10 machines. I suspect other online suppliers do as well.

At least they list them on their web sites. Have you called and found they aren't available?

I know S9 machines are booby trapped to not work without the ResMed adapters even if you get the right voltages. I'm not sure S8 machines will run off of 12V directly or not. ResMed has dire warnings that you need the ridiculously overpriced ResMed DC-DC converter for the S8 machines.

I do recall hearing that S8 and Respironics machines use the same DC plug but opposite polarities.

If you use a DC-AC inverter, don't use the it with the S8 machine, or it may damage the humidifier. S9 machines work OK with inverters.
Get the free SleepyHead software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
Post Reply Post Reply
#3
(02-01-2015, 06:39 PM)Breathetonight Wrote: I'm looking at a Resmed S8 as a camping Cpap to runoff a deep cycle battery. I found a little used S9 but Resmed does not support the unit any more and I haven't been able to find a Resmed DC power connection kit anywhere online.

Do you mean you found a little-used S8?

I think it is important to use the proper DC-DC converter to replace the machine's normal 115VAC Power Adapter, because using an inverter to produce 115VAC (to use the normal AC Power Adapter) would be much less efficient, requiring perhaps 40% or 50% greater reserve capacity in the deep discharge battery, which would cost more to get a bigger and heavier battery or would cost in terms of allowing less run time before the battery would become discharged.

Prices for used S9 machines are becoming more affordable these days. (For example, from Supplier #2 on the Supplier List.)
Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
Post Reply Post Reply


#4
ResMed S8 blower unit is rated at 24VDC at 2.5 Amperes. I think it actually draws a bit less current.

Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
Post Reply Post Reply
#5
(02-01-2015, 09:02 PM)justMongo Wrote: ResMed S8 blower unit is rated at 24VDC at 2.5 Amperes. I think it actually draws a bit less current.

I know the S9 is a 24 volt blower. I was under the impression that the S8 was a 12V system? Just wired backwards?

VERIFY EVERYTHING I SAY HERE BEFORE ACTING ON IT OR PROCEED AT YOUR OWN PERIL. It has been a long time since I messed with any S8 equipment and i have not had the opportunity to sleep at a Holiday Inn Express since then... In any case, the sneaky boogers at Resmend wired the DC plug backwards so nobody else's plug would work. IIRC it is center pin negative, outer jacket positive. So if you make your own plug, verify that .... And verify it before using somebody else's dc cord. Also IIRC the S8 used a 25 mm plug, but I could be wrong on that. As I said, it's been a couple years since my S8 died and went under that great slow recycling mountain on the southern edge of town.

OMM
Post Reply Post Reply
#6
Bottom view of S8 blower unit. Power requirements photo, left.
(400 Hz is for aircraft use.)
[Image: 13SEPT2013%20004.jpg]

Admin Note:
JustMongo passed away in August 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
Post Reply Post Reply


#7
(02-01-2015, 09:02 PM)justMongo Wrote: ResMed S8 blower unit is rated at 24VDC at 2.5 Amperes. I think it actually draws a bit less current.

In general, S8 VPAP machines are 24V, CPAP/APAP are 12V.

I'm not sure of the exact model numbers for each voltage.

Mongo have VPAP S. Mongo only pawn in game of life.
Get the free SleepyHead software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
Post Reply Post Reply
#8
The old s8 cpap apap needs a pure sine wave inverter. Using a normal modified sine wave inverters will over time burn out the blower motor and compliance electronics.

I ran an s8 on a pure sine wave inverer in the truck for years with no problems.

The s9. has a direct 12v power supply. That saves on battery drain.

Running anything off 12 battery via inverter will result in significant power loss through the inverter. This power loss gets really bad if you're using the inverter near it's wattage limits..

Most cpap at max pressure and max humidification draw. 185 watt 110v AC power . Plan on using a 400 watt inverter directly wired to battery. Use good heavy gauge cable from the inverter to battery. Light cable will mess up battery drain by overheating.

That's standard practice for cpap used by truckers in sleeper berth equipped semi trucks.


If you're looking for a camping setup look at the Transcend or z1 portable devices.

I've got a transcend as a backup. It's designed for minimal battery drain. But no humidification.

Check the CPAP review forum on transcend or z1.
(Just a truck driver with sleep apnea )
Post Reply Post Reply
#9
(02-04-2015, 04:26 AM)truckerdad57 Wrote: The old s8 cpap apap needs a pure sine wave inverter. Using a normal modified sine wave inverters will over time burn out the blower motor and compliance electronics.

Not according to ResMed. All the S8 machines are specified to run on MSW inverters as long as you remove the humidifier.

http://www.resmed.com/us/dam/documents/a...lo_eng.pdf

Get the free SleepyHead software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
Post Reply Post Reply


#10
(02-04-2015, 04:26 AM)truckerdad57 Wrote: Most cpap at max pressure and max humidification draw. 185 watt 110v AC power . Plan on using a 400 watt inverter directly wired to battery. Use good heavy gauge cable from the inverter to battery. Light cable will mess up battery drain by overheating.

Your number is too high. My S9 with pressure of 16 and humidification at 5 draws about 30 watts average on the AC power line. Measured with a Kill-a-watt device.

Check the ResMed PDF document for numbers for many operating conditions.

http://www.resmed.com/us/dam/documents/a...lo_eng.pdf
Get the free SleepyHead software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
Post Reply Post Reply


Forum Jump:

New Posts   Today's Posts




About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.

For any more information, please use our contact form.