Battery Power 
product Power Media Battery Power HyperJuice /product-images/power-media/hyperjuice-usb-c-battery-pack-100wh-27000mah.jpg /product/hyperjuice-usb-c-battery-pack-100wh-27000mah/ $66 Power Media USB C USBC 
Power Media · Battery Power
HyperJuice USB-C Battery Pack 100Wh, 27000mAh
You might also need
Battery Power 
10/15amp IP66 to Plug Adaptor
Battery Power 
10A 4 way IP66 RCD Power Board w/ 1.8m braided lead
Battery Power 
10amp / 10m Extension Lead 1.5mm Rubber Flex Cable (Green Tag)
Battery Power 
10amp / 10m Extension Lead Piggyback (Blue Tag)
Battery Power 