Can I ask what is the need for the controller and all the extra bits.
Why can I not get a solar panel and connect it to my battery and job done?
Maybe stick a 2 quid voltmeter on the battery and disconnect it if it's full?
You can do that , but solar panels will put out anything from 0 volts to 22 volts at any given time , the solar controller regulates that voltage in the same way that an intelligent charger does.
You can run as Nathan does and keep a close eye on it , but you will still be at most times cooking the battery .
With a controller you can leave on all the time , so from sun up its charging until sun down , before you start and long after you finish .
The 2 types of controller are ......
PWM - This one takes the voltage from the panel and reduces it to around 14 volt to feed the battery , the rest it throws away , now this could be anything up to 8 volts (Big waste of power)
MPPT - Does the same job , but instead of throwing the over voltage away it sends it though another coil and converts the over voltage into Amps , usually 20% more efficient , (This is called DC to DC conversion )
I will show you what to look for shortly , if you go cheap chinese route as i originally did .