Looking for a 12 v dc "PowerPack" battery that produces A/C

(...)

the smallest battery I can find that would

That is a good - sized battery. Your standard 100 AH trolling battery would be good for only about two day's sleep at 5 A drain.

'Course, if you can manage to recharge it daily, Bob's your uncle.

I think you require a less-hungry CPAP, practically no matter what you do next.

--Winston

(...)

home experience with the Xantrex and the cpap

Practically speaking, that is probably close enough, considering the negative effects of complete discharge.

As you mentioned, discharging the battery 70% in 5 hours leads one to believe that we are looking at 14% discharge per hour, or a total run time of about 7.1 hours before the battery is totally flat.

(70% discharge / 5 hours = 14% hourly discharge rate) and 1 / 14% = 7.14 hours total run time)

Your CPAP unit appears to be drawing about 3.36 A because:

Looked at another way, 3.36 A * 7.14 H = 24 AH

That is not *quite* as high as 5 A. :)

--Winston

Be aware that my memory may not be accurate on that matter. I did the experiment about 6 weeks ago.

(...)

experiment about 6 weeks ago.

Your ammeter measurement will show the real info.

If your battery is new, it could be more than 24 AH. And if it has some hours on it, it could be less than

--Winston