Does anyone know if this information is obtainable somewhere? RESMED's website has only newer product information, and I can't get any hits about the S7 on CPAP related forums. I do not have an original DC cord/adapter to check the polarity, I only have the simple AC cord with the "figure 8" IEC320C7 connector that goes into the S7 via the AC connection, and no way to tell the polarity of the DC jack without an adapter and cord that is so old it's not longer stocked anywhere.
I also am considering just using a Suaoki Portable Solar Generator (I can't post links yet) instead of cheaper batteries, and was wondering opinions on it as well. As then I would also have a battery back up option at home and when traveling, but the double power transforming would really be a waste if I could only plug in via it's AC connection and not use the DC power connection, not to mention the cost.