Can I add more solar panel let say up to 200 watt and adding two 2 volts battery using the same charges controller and power inverter?
You can wire solar panels in parallel (i.e. positive to positive, negative to negative). Preferably, the panels should be similar to allow the output voltages to track. Otherwise, it may be necessary to include diodes in series with each panel so voltage variations do not have an adverse effect. The other alternative is to have the panels charging individual batteries and then combining the batteries through diodes before using the inverter. This approach would require separate charge controllers for each battery. Not quite as energy efficient as each diode causes a voltage drop (and so a power loss).
That charge controller is notoriously cheap and burns up easily. If you are going add solar panels, also buy another charge controller to go with them. They can both be connected to the same battery bank. I don't believe the kit comes with batteries, so you would buy whatever size 2V battery bank your power requirements call for. The size of the inverter depends entirely on what you are going to power with it, not the size of the panel array. As long as you are not powering anything that is over the 300W rating, you don't need a new one. Just be sure to check the details of the inverter, is it 300W continuous, or can it handle up to a 300W surge? Also, it's a modified sine wave inverter instead of a pure sine wave inverter, so don't plug any sensitive electronics into it. They may not work, or you may get a buzz or hum from it.
If you put a black panel on the ground or on your house and don't connect it to anything, it will absorb solar energy (heat) during daylight and release it at night (radiation). Not exactly. Assuming the black panel establishes an equilibrium temperature, it's going to be losing exactly as much heat as it's receiving during the day. Some will radiate out into space, some will conduct or convect into the atmosphere. As a wild guess, maybe 50/50. If you hook up a solar panel in the same place but hook it up to batteries, charge the batteries during sunlight hours and using that energy to electrically heat the home at night. The panels will absorb solar energy during the day but will convert that to electrical energy in the batteries instead of radiating it back into space at night. The panels are only about 4% efficient, so it's the same situation as the pure black panel for 86% of the energy. The remaining 4% will get stored in the batteries and then converted to heat at night. That heat will eventually leak out of the house and warm up the Earth a tiny bit. I think it's much the same situation either way. With the black panel the energy gets radiated / conducted/convected right away. With the solar panel a small percentage is stored and not so much is radiated, mostly conducted and convected. You're partly right as a black panel is going to radiate more into space than a house. But you're taking about maybe some day about 4% of % of the differening radiation/convection/conduction fraction, of the Earth's surface area. Probably not significant.
