Backup DC power standardization with Photovoltiac battery systems?

[Sean Donelan <sean () donelan com>]

Are broadband CPE (ONTs, CMs, NIDs, etc) manufacturers and PV battery 
wall engineers working on any standardized CPE backup power connectors?

AC/DC/AC & wall wart DC again is inefficient and reduces runtime.

It would be nice if PV/DC battery wall and broadband CPE had a standard DC 
connector instead of the incompatible hacky/proprietary used now. A DC 
bus would be nice, but even the EU regulatory approach of requring a USB-C 
power connector on ONTs and Cable Modems would be a start.

All these darn wall warts are almost, but slightly different (5v, 12v, 
24v).  No -48v CPE?

I have enough EE knowledge to build magic DC boxes, but I would prefer a 
good UL-listed interoperable solution.