A grid-tied solar system without battery backup is a simple way to use solar energy at home.
Most homes nowadays use a grid-tied solar system without a battery backup.
The grid-tied inverter also called string inverter is connected directly to the power lines (the grid) that bring electricity into your house. This kind of solar system has solar panels, a device called an inverter, fuses, and wires to connect everything.
The solar panels create electricity when the sun shines. The inverter changes the electricity from the solar panels from DC into AC that can be used in your home or sent back to the power lines (the grid) if you make more than you need.
There are advantages to this kind of solar system:
- Cheaper: It doesn’t need batteries, so it’s cheaper than hybrid or off-grid solar systems.
- Easier to install: No batteries mean it’s simpler to set up and takes up less space.
- Credits for extra power: Sometimes, the power company will give you money or credits for the extra power you send back to the grid. This is called net metering and is different in every state/country.
- Less work to keep it running: You don’t have to take care of batteries, so it’s easier to maintain.
But there are also some disadvantages:
- No power when the grid stops working: If there’s a power outage, your solar system won’t work because it needs the grid as a reference point. It’s also a safety feature not to electrocute the repairman working on the power lines.
- Not independent: You still need the grid for electricity when the sun isn’t shining.
- Harder to change later: If you want batteries in the future, adding them to your solar system might be difficult and expensive.
Does a grid-tie system need batteries?
No, a grid-tied system does not need batteries. Your solar panels are connected to an inverter and then to the electricity grid.
What can I do if I want to add batteries later on?
If you buy a grid tie or string inverter, you must AC-couple a battery. You need a battery inverter/charger which transforms the AC power from your grid tie inverter to the battery. I have an AC-coupled system at home and use the Victron Multiplus II.
What happens to a grid tie inverter when the grid power is off?
The grid tie inverter will shut down because it is designed to work with a signal from the grid. This has two reasons:
- To protect the servicemen from electrocution who work to get the grid back online.
- It needs to read the frequency and voltages from the grid in order to send electricity to the grid.
Can you make a grid tie inverter work off-grid?
No, you cannot make a grid tie inverter work off-grid. It still needs the reference signal from the grid. If you want an inverter that can work off-grid, read my expert article on the best off-grid inverters.
How long does a grid tie inverter last?
An inverter typically lasts 10 years. This is because the capacitors have a limited lifespan. Most manufacturers give a 10 year warranty on the device.
Do I have to tell the power company of my grid-tie inverter?
Yes, you need inform your power company. You also need to check for the net metering options. If you don’t do this you might mss out on the benefits.
Do I need a charge controller for a grid-tie inverter?
No, you don’t need a charge controller. A charge controller is only needed in off-grid systems.
Can you have multiple grid tie inverters?
Yes, you can have two or more grid tie inverters or string inverters in parallel. You need to make sure they can communicate with each other to have their frequency in line.