A battery connected to your home solar system allows you to store unused solar power from your panels and later when the sun isn't shining is that stored power to run your house.
A solar inverter converts the DC power which is generated from your solar panels into 240V AC (alternating current) electricity that then can then be used in your house.
The warranty period offered varies between solar panel manufacturer, the longest warranties on offer tend to be around 25 years warranty on the panel performance, this warranty covers a certain level of output at given year time frames. Check with your Darwin solar panel installer what the details are for warranty on the installation. The panels may have a different warranty for other defects or problems that may arise with the panels so make sure to check what aspect is covered under warranty and for how long.
The installer of your solar panels in Darwin will usually offer a warranty which covers their installation of your solar system, this warranty will cover things like wiring, connections and the racks used to mount your panels.
A micro inverter aims to give you higher system output when there are shading or different levels of sunlight hitting different panels. Without a micro inverter and all panels are in a string, shade on one panel can reduce the output for the entire string. Adding micro inverters to a system will increase the cost but be able to increase the output of your solar system in Darwin.