Yep i didnt look too much into all the info into solar charging, haha found the more I read the more confusing it became and then hiw it doesnt work in the uk and bla bla bla.......so i decided to just get one and try. The flow of electricity is one way, so it isnt draining any power from my battery.
Then I simply rely on digi reading the battery voltage rather than using any smart boxes for solar panels. Then I check to me the main point, that (i think im right in this) if the battery is charging more than 14.5v it will kill off the battery more than helping it. So a simple disconnect of the wire sorts that and when the voltage start to drop to 12.7 // 12.8 i reconnect it.
Simples.
But of the one battery i only run the sureflow pump. I have a small 12v battery for my electric reel, which sometimes i will connect my smaller panel too if required.