to be honest I'm using what i was using on my S1 and S3 and its looks like they will work just fine with my S5 once i have them .

but i use these


http://www.amazon.com/gp/product/B0090I9W66/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

http://www.amazon.com/gp/product/B00EB7UITQ/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

http://www.ebay.com/itm/EVGA-SuperNOVA-1300-G2-Power-Supply-120-G2-1300-XR-ATX-1300W-80-PLUS-GOLD-/281435888657?pt=LH_DefaultDomain_0&hash=item4186e2dc11


According to the video on face book with the CEO of bit main the ^  should power two S5 with no issues. the ones i linked on amazon I got deals on as used  but were really new and if you know how to you can use the 6 or 7 year warr they come with  no question asked if you have to  . but right now i can't say i would  recommend any thing, waiting for my S5 to come.