For my trip to flock earlier this year, I picked up a external battery pack, since I wasn’t sure when and where I would have power and wanted to make sure my laptop and phone and such could last for the long plane flight from us to europe.
I looked around and ended up getting this one from amazon: http://www.amazon.com/gp/product/B00DN0KBXU/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
It’s pretty big and heavy, but it packs a lot of power as well. It’s got 2 usb ports (one with higher Amperage) and 1 DC out that can take a variety of tips to connect to a variety of laptops and devices. I got a extra tip for my yoga 2 pro, but it turns out that was also one that was included. In addition to having power in places where you have no power it’s been very handy on regular trips: Hotels often provide few power outlets or they are anoyingly placed. With this device I can plug it in, then plug usb devices (phone, etc) and laptop into it. No need to carry the usb to AC adapters and find them and plugs for them, or get out my laptop’s power brick.
It does have one anoying quirk in that if _anything_ is plugged in it’s on and draining, so you can’t leave just a usb cable attached without it running (slowly) down.
Despite the weight I am going to continue to carry this on trips and would recommend it to anyone with lots of power hungy devices.