i hope to do something similar
so far i have found solar panels are on all the time even at night. There is always light. I wonder if solar panels also pick up infrared, which is emited by all life. even humans.
sadly so far it is very hard to actually charge batteries. Not sure why.
currently i have one 13v 108watt solar panel, 6 volts at night and 10 -14 volts at 11am - 8 pm.
in theory i would need 4 of these panels to remain at 12v's 24/7.
I think you are vastly overestimating what
Power you will get from a solar panel. What matters is not an open circuit voltage but Voltage * Current. There will be no power available at night & even during daylight hours you will see the Power increase and then drop off again over a 12 Hour period. Exactly how this happens will depend on your location and how clear the sky is etc.
Here is an example of what to expect.