said by public:Of course it is possible to design a dc/dc converter that does that.
In your case the problem is likely voltage drop over interconnections at high current.
Cheap off the shelf designs are rarely more than 90% efficient.
I dunno.. We regularly only get a 1.2-1.5V drop when passing 3-4 thousand amps in our equipment.
Of course, this is wired with 8 pairs of 444mcm DLO cable as the interconnects
Our 10,000 amp systems have a voltage drop about the same with only 4, 750mcm cables as the interconnections.