Found these 600 watt step-up convertors on ebay

[153stars]

10 Lot Boost DC-DC Converter Power Supply Step-up Module 12V-60V to 12V-80V 600W | eBay
1,2,3,5,10 lots 45 for 5 They have round plug on the boards also should stay cool. A bit bulkier than the popular ones.

 

[153stars]

guess I should of bought a lot of 5 before posting all 5 &10 lots gone in 12 hrs