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.