Grid-Tie Inverter

In land scarce Singapore, it is very difficult to go completely off grid. Off grid means that you no longer need to depend on SP services main power to supply your household's demands on electricity.

Off-grid system requires backup batteries to power the electrical appliances during night time and cloudy days. Batteries are heavy investment in an off grid system. They can easily take up one third of the cost of a solar generator system.

Batteries require regular maintenance and have limited shelve life, typically 2 to 5 years depending on the types of battery.





What is a Grid-tie Inverter? 

A grid-tie inverter is a device which convert DC power input, such as the power from the solar panels, to 230V AC power output which is commonly available in all household in Singapore.

It also synchronizes the sine wave of the it's output to match the sine wave of the AC main in your house.

 What to look out for in a Grid-tie Inverter?

1st thing you must check is what is the total output of your solar panels and the voltage of your solar panels output. For me, I have 6 x 30W panels and 1 x 100W panel with a total output of 280W at 12V DC. So I selected a 300W grid-tie inverter which is sufficient to handle the output from my solar panels.

The next thing is to check the output of the inverter. It should give 230V AC that we use in Singapore and not the 120V AC common used in North America.

Some people will also look at the efficiency of the inverter. For me, it just a small setup, so I look at the cost of the inverter, which is less than S$200.





How to Connect Grid-tie Inverter?

The setup is very simple, even more simple than the basic setup of using charge controller and batteries.

You just have to connect the output of your solar panels to the input of the grid tie inverter. Red for positive and black for negative.

Next you connect the output of the grid tie inverter, which is a 3 pin socket with the AC cable provided (similar to a PC power cable). Then you connect the other end of the AC cable to a wall socket.

You can purchase a AC power monitor meter like the one in the picture and place it in between the wall socket and the output of the grid tie inverter to measure the power produced by the grid tie inverter and hence your solar panels.





Which setup would I choose? Grid-tie or Off-grid


If you have solar panels of more than 100W, I would recommend that you go for grid-tie system. It is simple, with fewer components and requires almost zero maintenance. For smaller system of less than 100W output, off-grid system with small battery and charge controller is more cost effective and can provide you with more learning experience.

PM me (Cheehui68) in hardwarezone.com.sg if you need further discussion and help.