One option you have is a regular POE switch which can be run off 12v then a POE adapter for 12 or 24v POE devices from like WIFI Texas
on Amazon. For cameras or devices.
Like this: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I recommend if running a 12v or 24v electronic devices off battery
one can use a DC step down converter set at about 13v to limit the voltage during charging
or equalizing batteries
etc which can reach 15.8v. Most of the networking devices are 12v and a 2.1mm plug
available on Amazon etc. One can connect 2.1mm pigtails for multiple devices like security
cameras or routers etc. Just don't overload the converter max amperage output.
An adjustable step down converter
To make a nice little power brick you can use a regular shallow blue plastic electrical
box with a hole in each end and screws holding board in the bottom. Then a regular blank cover plate with holes drilled in it for cooling
Also to protect and minimize corrosion
it helps to smear Dielectric Grease on any power or data connections especially if you're in saltwater areas.