Ok, so how would you build this circuit?
I want a 12v 5w solar panel to run/charge a 12v lead acid battery to be connected to a surveillance camera that runs on 5v. The camera supposedly use 0,5amps, probably more at night because of the night vision.
I want this to be able to run continously with the solar panel as the main power source during the day and the battery during the night.
Cost is important and so is realibility.
As you already know, my knowledge is limited so your explanations need to be thorough please.
You are likely to get sticker shock when I tell you the answer since you balked when I pointed you towards a $15 part...
Your 12V 5W solar panel is drastically undersized a 12V 5W panel (that is maximum output under direct full sunlight by the way not real world output) when it's operating at maximum capacity it's pushing 12V at about 417mA... But, sunlight is vary rarely direct and full... So lets knock that down to 12V @ 200mA as an average over the entire day, believe it or not 50% (or less) capacity is not far fetched, especially if the panel is not tracking the sun... So 12V @ 200mA is about 2.4 Watts output... You are running a camera that draws 5V @ 500mA or in other words wants 2.5W of juice... See a problem already? If the conversion from 12V to 5V was no lose you still don't even produce enough energy to actually power the camera unless the panel is running in good lighting conditions, let alone any excess to actually charge the battery...
There is also the problem that the conversion from 12V to 5V is not perfect, with a good switching regulator you can get about 90%, as it is you are far bellow 90% with your current regulator making things even worse...
Now, you not only need to consider running the camera for those 10 daylight hours you also need to have an excess of power to charge the batteries to run the camera for 14 more hours... AKA you need to gather 24 hours of run time in 10 hours, so at minimum you need to generate 2.4 times what the camera is drawing, and right now you are below even 1 times...
In short without working all the math to do what you want you are going to 'realistically' need about 4 solar panels, 5 or more would be more reliable... But, then again reliable and solar are kinda contradictory, a week of clouds and rain can result in some very unreliable situations even if it was calculated to work with overhead... That is unless that overhead is way overhead, but you don't seem to want to go there as you keep scaling things back.... Ideally you would invest in as many batteries and solar panels as you can realistically justify and do your best to bank as much energy, days worth, when you can and hope it's enough to cost for the low light times... Cutting corner or not making a big overhead will result in unreliable situations...
