Just make sure it has more than 2 amps output. I bought this one http://www.amazon.com/Poweradd-Charger-Portable-Foldable-Bluetooth/dp/B00HMXKMVU?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o04_s01 and its only a 1 amp. Charges my iphone 4s decently - but won't charge my new samsung for shit.