CPAP system backup/camping power

I built a small solar/battery system that can easily provide power for my CPAP all night long. It includes an 80watt folding panel, 15amp PWM CC, 65Ah Blue top Optima battery and a 300watt inverter. I use a hand cart to move it around and the battery sits in a box that has terminals, 2 cigarette plugs and a power level indicator. I can get about 200wh out of the system at night and get the battery recharged during the day. Total cost was about $500 which I doubt you can find prepackaged anywhere. My only issue is that I should have gone with a 100watt panel for that 65Ah battery.

I have found a DC to DC converter on Amazon that's for the Airsense10. Apparently it up converts to 24vdc for the A10 and massages the 12vdc to 12vdc for S10 machines needs on the ID resistor in the connector of the unit..Purchase the female cig lighter / jumper cable at the same time as it's not included. This non-OEM converter is less than half the cost of one from Resmed. Going this route is easiest. Now for the battery. Input DC: 12V-24V~12A Max Output:24V 3.75A 90W ;--Please confirm the specifications and plug size before purchasing!If you can't make sure,pls feel free to contact us
Compatibility: ResMed Airsense 10 Series: AirSense 10, AirSense 10 Elite, AirSense 10 AutoSet, AirSense 10 AutoSet for Her CPAP Machine with HumidAir Heated Humidifier; Fits Resmed CPAP and BiPAP Machines S10 370001 +24V 3.75A 90W; ResMed AirCurve 10 Series CPAP and BiPAP machine: AirCurve 10 S BiLevel Machine, AirCurve 10 VAuto BiLevel Machine with HumidAir Heated Humidifier

Did you ever price out a 30 Ahr LFP battery? That would have eliminated the need for a cart and the charge efficiency of LFP would have let you use a smaller capacity battery than the 65Ah Optima. Also, LFP doesn't self discharge like lead so it would stay fully charged between uses.

Back when I built that system I had not learned enough from others what not to do. Going with an LFP battery would have made my system much more portable and easier to use.

I checked my old paperwork. My Autoset 10 has a 24V supply. To operate off exact 24V and fool the machine into thinking it has an 85W supply pack, the center pin must look like a 3.3V source connected to a 2.7K resistor. Only two resistors are needed to do this. The Thevenin equivalent is a voltage divider with a 33K resistor to the +24V and a 3.3K resistor to common. These values are common and close enough that the exact 1% resistor values are not needed.

I'm trying to visualize this. Some how one still needs to get to the center pin. Is there a cable one must hack?

I just cut the cable from the 120V AC adaptor. You could put a 3 pin plug on each end to connect it back together when AC is available. I have not found an off the shelf cable that will work. A HP plug is similar but has a plastic spacer on the end which tells the machine the plug isn't fully inserted. There are boost converters that can adjust 12V to 24V and that is adjusted to 24.0V DC. The plug has three connections. Outside barrel, inside barrel, and center pin. Believe outside barrel is neg and inside is positive 24V. Center pin is 3.3V supplied thru a resistor.

In the above mod the two resistors are in series with the center pin connected to the junction of the voltage divider.