What is AC Coupled Inverter?
If you already have a solar system and wish to add batteries to this system, then an AC Coupled Inverter is essential device, because it is the main way people add batteries to their system. The function of an ac coupled inverter is to reconvert AC power to DC power and store it in the battery, because the battery stores DC power. Therefore, it is generally used in conjunction with another solar inverter.
Why and when you need AC Coupled Inverter?
As mentioned above, when you already have a solar system and need to store the power, you need to use the AC Coupled Inverter. Because when using a solar inverter, it will only produce as much power as possible, especially in the middle of the day when the sun is at its peak. But in a blackout, for technical and safety reasons, solar systems will not work during power outages, and you want to get power from battery during that time.
So if you need to retrofit your system – adding a battery, the AC Coupled Inverter is undoubtedly easier and cheaper because you don’t need to replace any of the parts of existing system.
The cons of AC Coupled Inverter
But there are still two main disadvantages.
First one is the energy loss in conversion, also called that the efficiency is not as good as DC coupled system. It is well known that the power generated from the solar panels and stored in the batteries is DC power. The power we use in our homes is AC power converted by the solar inverter. The AC coupled inverters convert AC power to DC power again and store it in the battery, which means two conversions are made, so there is a loss of energy in the conversion process.
Another reason is that it does not work when off-grid. Battery charging and discharging require AC coupled inverter’s support. Once run out of battery power, it will not be able to charge the battery during a blackout.
What is hybrid Inverter?
In a DC coupling system, we will use hybrid inverter. Unlike solar only inverter, hybrid inverter is an intelligent inverter that can operate in various modes, including utility priority mode, battery priority mode, etc. It stores excess solar power in the battery, decides when to charge and discharge the battery, and also decides whether to supply power from the grid. Hybrid inverter also can work in blackout.
How is it different from AC coupled inverter?
In a DC coupling system, we will use hybrid inverter. Unlike solar only inverter, hybrid inverter is an intelligent inverter that can operate in various modes, including Grid-tie mode, Hybrid mode, Backup mode and Off-grid mode etc. It stores excess solar power in the battery, decides when to charge and discharge the battery, and also decides whether to supply power from the grid.
One of Off-grid inverter is Growatt SPF 5000 ES. It can work without battery to saving system investment cost.
Solar power is converted only once in DC coupled PV system. Only one inverter is required, which facilitates installation, reduces hardware costs and makes the entire PV system more cost-effective.
Besides, backup power can be easier with DC coupled, because of no need to be built between two inverters like AC coupled, it’s just need one Hybrid inverter.
2 Comments
Leonard Faast
Hi,
I have a Growatt MIN 5000TL-XH currently operating with a 5 Kw solar system.
I purchased a GREEN BANK LB48200 battery and was told that these two units are NOT compatible !
Is this true ? Can you advise of any solution or other assistance ?
Thank you: Leonard
Sunterra Solar
Hi Leonard,
Thanks for your inquiry. Growatt Min 5000TL-XH is only compatible with ARK XH batteries.