AUKEY Power Pack 30000mAh, 2.5V 2.4A Output, 1.5V 2A Lightning Input and 1.5V 2A Micro USB Input

https://www.amazon.co.uk/30000mAh-Output-Lightning-Speaker-Charging/dp/B01K9HB5VQ/ref=sr_1_27?ie=UTF8&qid=1492064728&sr=8-27&keywords=aukey

Wow, 3000mAh - should last forever. It's superbly built and packaged, on-charge right now and I'll report on number of charges etc later. Has the huge benefit for us Mac people that it's got a Lightning in / out.