[Mark V U.S. Sellers, from SMA Adapter's to Wi-Fi Adapter's and so on. Post your findings: Dec 3 Update.]

You can add this battery: http://www.amazon.com/gp/product/B00BB5VQCE/ref=oh_details_o03_s01_i01?ie=UTF8&psc=1

I can vouch for it after using it for a couple weeks now. From what I can tell so far it will do the Pineapple for about 22hrs by itself, or both the Pineapple and Kali-Pi (with 4 radios between them) for roughly 8-10hrs. And you can be charging it while its powering both. Pretty happy with it so far.

http://www.ebay.es/itm/Double-USB-50000mAh-Power-Bank-External-Battery-Charger-For-Mobile-Phone-PSP-8-/261366945475?pt=LH_DefaultDomain_3&hash=item3cdaaf16c3&_uhb=1 u belive works fine with your setup?