Dreamstation DIY Battery backup

I have a Dreamstation CPAP. I'd like to homebrew a battery backup. The power supply cable has three wires, black, white, blue. Does anyone know how to wire this to a 2 post battery? I was planning to use power poles to battery clamps, but I am unsure how to move from the 3 wires to 2.
Thanks

Wire a cigarette adapter on to the battery, then use a DC cord specifically designed for the DreamStation.

$30 bucks at CPAP.COM

https://www.cpap.com/productpage/pr-dre ... ed-dc-cord

You can also get cheaper off brand DC cords.

Thanks for the advice. I have both ordered.
I'd still like to know how to take a regular Dreamstation power supply, cut the cable that connects to the Dreamstation at the power supp and wire that to battery clamps.
Again, thank you for the input.

http://www.apneaboard.com/forums/Thread ... ery-Cables

3 conductor cable:

Outer Barrel: Common
Inner Barrel: +12v
Centre Pin: 20K ohm resister +12v . In the topic there are ambiguities regarding resister. Originally claim to be 100K, then 20K, then 24.3K.

The connector is similar to that found on many laptop chargers.

Thank you so much