Resmed S9 stops and restarts during night on battery

I need your help.

My wife's Resmed S9 with humidifier stops and restarts several times during the night when we are running off DC battery power in our travel trailer.
The S9 runs fine on AC at home or in the trailer. I am using the Resmed 90W DC converter, it's plugged into the 12V cigarette lighter style plug (factory installed) at her bedside.

At first I suspected the converter was bad, so I purchased another. Unfortunately, I have the same problem with both. The S9 runs for, say, 2 hours, stops for about 10 seconds, then restarts.
It will stop and restart many times during the night, which disturbs her sleep.

The 2.5 KWH battery bank in the trailer is fully charged every day by roof mount solar panels. At bedtime the battery reads 12.8v and when we wake up it's at 12.5v, so it seems we have plenty of battery for the CPAP.

Next steps I've considered :

wiring a temporary cigarette style plug to eliminate the factory installed plug as a problem, unlikely as that might be
putting together another power adapter but I'm uncertain what to do with that third pin in the DIN connector.
a programming change to the S9, but I'm not certain what that might be.
running the S9 without the humidifier
swapping out the S9 ...

Thoughts?
Surely someone out there has encountered this behavior.
What's your solution?

Thanks,
-dws

WestOfGolden wrote: ↑

Wed Jul 05, 2023 8:37 am

running the S9 without the humidifier

Keep the humidifier attached, with water, but turned off. This is referred to as pass-over humidity.

This way she'll get some humidity, but without the *huge* draw the humidifier uses. Also ensure if you're using a heated hose it's off. Fortunately, in the summer months relative humidity is so much higher that pass-over humidity is good for many.

Thanks for the suggestion, I hadn't thought of that option. She likes the idea, so we'll try it.