Connecting solar panels to the grid
In the illustration we show the excellent but discontinued Soladin 600 inverter. I’m still using it in this example because it shows how easy it is to offset you electricity consumption with grid tied solar panels.
Basically a grid inverter enables you to hook up two or three solar panels and push the electricity they generate into the mains electricity at home. It’s possible to connect more than three however you need to make sure the solar panels total output voltage at the lowest recorded temperature for your installation does not exceed the maximum input voltage of a grid tie inverter.
Solar panel output voltage differs considerably. For the Soladin the output must NOT exceed 149.9 Volts or you’ll fry the inverter.
Here’s a diagram of a simple grid connected solar panel set-up. Fuses, breakers etc have been not be shown for clarity! Alos please read the note at the bottom of this page.
The three solar panels are connected in series so the output voltage is higher. Just same as putting batteries head to tail in a torch to increase the voltage so the bulb illuminates sufficiently. Each solar panel / module outputs about 33 Volts so all three in series give us 99 Volts DC.
There are two cables that connected the panels to the input of the Soladin 600 and in our simplified setup the 230V output is wired to a mains socket. You need to make sure you follow the correct local regulations if you just want to plug it in. We can’t possibly encourage you to do anything but follow the local regs but we are certainly aware that a lot of people do just plug it in.
The clever bit of electronics in a grid tie inverter pushes the power into the mains so appliances use the generated solar power first then get the rest from the grid.
If the solar panels are generating 400 Watts and you are using 900 Watts in the house then 400 Watts of power come from the solar panels and 500 Watts come from the grid.
If you are using 300 Watts of power and the solar panels are generating 500 then the excess 200 Watts flows bakc out of your house to the grid for you neighbours to use 🙂
Most houses use at the minimum 1000 Watts of power so most of the time the power generated by the panels and converted by the grid tie inverter is used consumed by the house and therefore not exported. It really quite simple to make hay while the sun is shining.
One of the other great features of the Soladin greid tie inverters are the computer ports / bluetooth that viw which you to change the settings and monitor the output of your grid tied system.
The Soladin 600 used to be supplied with a two pin plug. We were frequiently asked by customers if it is ok to just plug it in. Well it’s physically possible and it will work but you should NOT do this. Please always ask a qualified electrician to install the correct ancillary components so any grid tie solar system conforms to all the necessary regulations.
There are also some rip off versions with faults that could start a fire. Please be careful if you buy one second hand off eBay etc.
As I mentionened earlier we don’t stock the Soladin 600 any more but we do stock the superbly efficient range of Steca Coolcept grid tie inverters