recharge battery without cpap? hdm/breas z2/z2 extended life battery

[qwertyuiop]

I have a z2 small travel cpap from breas/hdm. I need to use it off grid for multiple days, then recharge in one night before using it again if grid for multiple days. I'm considering buying the extended life battery with powershell and two additional batteries. However, this will only work if I can recharge all 3 batteries at the same time. What I've read says that the cpap needs to be inside the powershell in order to charge. Is this true? Any other way to charge 3 of these batteries simultaneously?  Thanks for any help you can offer!

[Sleeprider]

What is the intended use. It makes a difference for weight and cost. Is solar recharging an option?

[qwertyuiop]

Solar is possible, but seems like a pain. I would rather have 3 batteries that I can recharge all in 1 night for the next leg of the trip. My goal is to have 3 nights charge in a light package that I can carry on me with the ability to recharge in a single night.

I found that the battery inside the z2 powershell extended life battery is this the RRC 2054-2. RRC also sells a charger for this battery, but, it is really expensive: $140.

[Sleeprider]

Let's try again...hiking biking, motorcyling, sailing, car-tripping. What is going on here?

[qwertyuiop]

I currently use a regular cpap with a full/large/heavy Maine deep cycle battery for car camping. I'm working on the solution to do 3 days of hiking at a time, with the ability to do 3 additional days with only one night with access to electricity in between.