Backup Battery Recommendation for High Pressure and Humidity

[SarcasticDave94]

If I'm not mistaken, generically speaking, battery power is good enough to run Amateur radio equipment if/when house power goes out. So if it's clean enough to not interfere with a ham radio operation, I'd think a PAP would be fine with it too.

PS there are batteries available for radio specific usage that are guaranteed to be quiet, I'm not exactly referring to these, but note the option exists BTW there are GO kits that power radios that may offer decent battery power in a box...not always exactly known for economy pricing however...was just looking up some items on West Mountain Power. Would probably be overkill for PAP use but here it is.

73s from K9DWB, a General class ham operator.

[Jerry Sends]

Costco has the best prices on marine batteries in my experience.

[sleepyBuzz]

Right now I'm leaning towards a dual battery config of the freedom cpap battery with the 24v converter. That would give me approx 200Wh and would be a more traditional cpap battery that has a passthrough but would cost nearly 500 all said and done. 

First, I wanted to describe my experience with using the Freedom CPAP battery, as a warning to others who may be considering it. Over the last 3 years, I have used both the original Freedom and Freedom 2 batteries in passthrough mode. Each time, the battery generated a tremendous amount of heat immediately prior to failing. The first one (Freedom) worked for 20 months and then melted the Dreamstation adaptor that sat on it as it failed. I put a trivet underneath the replacement battery (Freedom V2) to protect my night stand, which turned out to be a great idea because it also overheated and failed last night after 16 months of use. Both times, I contacted Battery Power Solutions about this possible fire hazard as their marketing clearly states that their battery can be used as a passthrough. I am finally ready to move on from them as it seems like the batteries only last less than 2 years and they are pricey.

Because of the Dreamstation recall, I am now using the Resmed AirCurve 10. It's a BiPAP, set at high IPAP/EPAP levels, and high humidity. All the things that kill battery power. My primary objective is to keep the BiPAP on when my house experiences quick (1-3 second) power sags. The secondary objective is the prolonged power outage (e.g. hurricane season). So I am considering a two-step solution.
 
Primary objective - purchase a standard 600VA UPS for daily use to get past those quick power sags/interruptions.
Secondary objective - create a transportable battery system that would normally stay in my garage, until there is a prolonged power outage. I have a small hand truck that I would strap a marine battery box to. Inside the box would be the Duracell Group 24 deep cycle marine battery and the ResMed Mobile DC Power Converter Cord. 

My specific questions: 1) Although the ResMed converter cord comes with a battery/cigarette lighter adapter cable, I'm wondering if I should still purchase the NOCO 12V Adapter cable because it has a fuse and I'm using such a hefty battery? 2) Battery tender or no? 3) What kind of maintenance or conditioning would I need to do to ensure it's good to go when I need it?