How Much energy does Solar Panel Produce,and How long can Solar Panels go without maintenance.
There really isn't any maintenance you need to preform...all you really have to do is clean the surface once in a while. However cleaning the surface is not crucial. A rough rating for a panel is about watt for every 9-2 square inches.
Solar panels are available in a wide variety of power ratings.? Energy is the sum of power over time, so how much energy a panel produces depends on the intensity of the light hitting it and how long it's applied. I understand that current single-crystal silicon PV panels are warranted to produce ~85% of their rated output for 25 years.? Most will do better, and will produce useful output for perhaps 50 years or more.
The available energy is a function of several factors including insolation (sunpower) mounting angle, gathering area, type of cell and conversion efficiency.
Solar panels come in many kinds, using a variety of technologies and sizes, but the most common is still the crystalline silicon type. The power produced is variable, but the better ones you can buy approach 20% efficiency, and the peak energy from the sun is 200W/m^2 (Watts per square meter). This only occurs when the panel is lined up with the sun on a clear day with the sun high in the sky. The efficiency is also affected by how the electrical energy is taken from the panel, and the temperature of the panel. In the full sun the temperature approaches 60C, so the voltage drops. The links below provide a lot of information about such matters. A BP panel 50mm x 674mm gives a peak power of 20W. This is .07 square meters. As you can see this is very close to 20%. (The third link). However this is less in practice because the sun may not be full sun and may not be perpendicular to the panel. The output drops as the cosine of the angle to the sun, more or less. Even with peak sun this would produce only about 00W charging a 2V battery directly, unless an electronic Maximum Power Point Tracking (MPPT) charge control is used.
