High voltage DC point to point transfer
Alright, over 50 meters...



The real cost of losses is the cost of batteries whose energy will be wasted to heat the wires.

At 52 W/m the 48V 35mm2 cable better not be buried in a conduit. Even the 50mm2 cable should get quite warm.

Going with 50mm2 however, losses are only 7.4%. Is it possible to step from 48V up to 230V then down to 48V again with losses much smaller than this to make it worth it, for less than 415€? Probably not. 90% efficiency is already pretty good for a UPS, and that's 10% losses already.

Also the power electronics are a point of failure.

I'd go with the 50mm2 48V cable.