Consulted the manual, again.  On the same page as the cig lighter
is the power ports in the cargo bay, like you said.  But, they too run
off the ignition switch, ie; accssy or run engine.
    So, I need to know where to install a fused jumper from the cig lighter
to a line on the hot side of the battery.   It ought to be in the engine bay,
on the fire wall, some electrical box.  Need to label it clearly so's any
service tech just don't rip it out.  Fused no more than .5 amp, probably less.

Bought my 2012 Forester April 23, 10yrs old, so no warranty to violate

nuclear powered charger (solar panels from Harbor Freight Tool) 

that's why I'm looking for a dash doily, to secure the SP

 

I must be missing something really obvious, if it is a battery charger then why not connect it right at the battery?

the round power ports inside also have a 'fusistor' on their backside and can never handle much current.

 

You may need to email the manufacturer of your charger (is it a trickle or maintenance charger???) for some connection guidance, and/or find a local auto electrics guy to help or install a solution for you.