Battery Power 
product Power Media Battery Power /product/3-pin-to-d-tap-power-cable/ $25 Power Media D Tap DTap
Power Media · Battery Power
3 Pin to D-Tap Power Cable
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 