Duracell Powerpacks - Camping - ReMed S8

I've read most of the posts on battery back-up. For my requirements I think one of the Duracell Powerpack options will work for me. My question is can anyone validate/calculate the power time I will get from the three Duracell PowerPack options?
I use the ResMed S8 Elite II, without the humidifier, at pressure setting 11. My plan is to plug into the AC jack on the powerpack. Concerns are cost and weight of the various Duracell options.
Duracell PowerPack 300 - 240W max continuous
Duracell PowerPack 450 - 340W " "
Duracell PowerPack 600 - 480W " "
I will be camping in mild temperature ranges.

I have the 600 model for power outages at home. It lasts 1 night [8 solid hours] on ResMed S8 autoset II without humidifier. I 'think' it will last second night but fortunately never had to try.

Thanks. I bet if I used the DC option (no inverter) it would provide even more power time. But I don't want to spend $80 on the S8 DC-12 cord.

Info on the 600 Watt one:

viewtopic/t49452/viewtopic.php?f=1&t=45 ... 37#p411015

Guest wrote:Thanks. I bet if I used the DC option (no inverter) it would provide even more power time.

Probably about 10%, maximum. The efficency of contemporary Inverters and Switch Mode power supplies in generally quite high.

Cheers,

Bill