High voltage DC power line for batteries
Terrible proposal - you harvest all that energy and waste it in heat using a potential divider. A potential divider on DC can only be achieved using resistors and these will fry if you try and take any sensible power from them.

You can use a SMPS wall-wart - they'll operate on DC - after all they convert the power AC to DC only to switch it at high frequencies through a transformer to a low voltage ac then rectify it. Give it a try but choose one that is capable of working down to 85Vac.

CAUTION - potential high voltages that could hurt a lot - be careful