It's a real problem on the small boat I have now. I have just a battery
on shore charge which will run the Ship to Shore and Depth
for a six hours. Outboard
has no electrics.
Usually I have to turn off the radio
just in case I really need it. Night lighting
is the same, just not enough for more than a couple of hours.
I'd get a 900x600mm up where the hatch
slides forwards and covers it. From experience my battery
will always be good to go, and it will extend my daylight running but it's not going to be enough to run radio
gauge but the battery still won't do the night lighting.
The flexible ones seems to charge from dawn to dusk, the rigid ones give more amps for less hours.
If I did the big Prout again then I'd use port and starb'd control units so the working ones aren't being wasted leaking through the shaded ones. Plus I have a spare on board that I know works!
The eight 600x 200 mm panels on that ran a 24v fridge that froze milk (lasted months like that) chilled meat to the bone, etc. And ran decent interior
lighting, mastheads for two to three days but did benefit from whatever engine
running we did.