All in one solar system is most welcome by DIY users. An all-in-one solar system should include hybrid inverter and battery storage as well as solar panels. From most people's experience, solar panels should be very easy and there is no compatibility problem. We should focus on the battery storage system and inverters. Different from traditional batteries, LifePo4 battery energy storage system normally requires building communication with inverter.
By this way, the battery system will tells inverter when need to charge it and stop at a certain condition. This will be more smart way then BMS protection actions. Of cause this will help your lithium battery storage system gain a much longer service life then those one without communication.
There are many different brand inverters like growatt, goodwe, sol ark, eg4 all in one inverter, ehv48, 3000w, 5000w inverters. We need select the right watt inverter in terms of load watt and solar mttp watt. Of cause a RS485 or CANbus communication are also important. This is basic function allows you build battery system communication with inverter.
Solar energy storage inverters are the key to improve your experience with solar system. The price for hybrid inverters are getting much cheaper then years ago. And now, most of inverters already has built in mppt and battery charger function from AC.
A Hybrid inverter is an intelligent inverter that enables the storage of excess solar energy in a battery system for self-use. Hybrid inverters function like a common grid-tie solar inverter but can generally operate in one of several different modes depending on the application, this includes battery backup mode which provides a limited level of backup power in the event of a blackout. Most hybrid inverters can also operate without a battery and function just like a grid-tie solar inverter by exporting excess solar energy to the utility grid.
Three main types of hybrid inverters
- Basic hybrid inverter for solar storage
- Hybrid inverter for solar storage and backup power
- Battery energy storage systems (BESS)
BESS systems are basically a hybrid inverter together with a lithium battery in one complete package which usually about the size of a fridge. However, like most appliances, there are many features and capabilities which differentiate the wide variety of BESS systems available.
Off-grid Inverters
Off-grid inverters often referred to as multi-mode inverters, are much more advanced and powerful hybrid inverters that can operate with or without a grid connection and offer instantaneous backup in the event of a blackout. These inverters can also backup very large loads like air-conditioners, pumps and heaters. Many of these advanced multi-mode off-grid inverters also have very high pass through power capability so separation of essential loads and non-essential loads is not required.
Lithium Battery Backup
Sungrow hybrid inverter with battery and add-on backup power box.
To function as a backup power supply a hybrid inverter must be able to isolate from the grid during a blackout and use battery power to back up any household essential circuits**. Most modern hybrid inverters have the ‘grid isolation’ feature built-in but some hybrid inverters do not, this means they cannot operate in either backup or off-grid mode. However, often an additional backup box or EPS (emergency power supply) is available to enable this feature. If grid stability is not an issue then this simple type of hybrid inverter would be a good economical choice.
More advanced hybrid inverters can operate in backup mode indefinitely and even function completely off-grid providing the loads are manageable and there is adequate sunlight all year round. However, dedicated off-grid inverters and high capacity batteries are recommended for off-grid solar systems due to the high continuous and surge power rating required to run a whole house completely off-grid.
**Essential circuits are basic loads (circuits) that can be easily backed up in the event of a blackout. This includes simple things like lights, fridge's, TV's and computers. To back up an entire house generally requires a more powerful AC or DC coupled multi-mode inverter or an off-grid system.
Hybrid Inverter Operating Modes
Most hybrid inverters can be programmed to function in four different modes:
- Grid-tie mode - Functions like a normal solar inverter (no battery)
- Hybrid mode - Stores excess solar energy during the day to be used in the evening to increase self-sufficiency.
- Backup mode - Functions like a normal solar inverter when the grid is connected and automatically switches to backup power mode during a grid outage
Off-grid mode* - Operates much like an off-grid inverter and uses excess solar to charge the battery and power the loads without a grid-connection.
* Only a select few hybrid inverters are designed to be used for off-grid solar power system and have the capacity to start and run a backup power source if required. Hybrid inverters with off-grid mode include ehv48 and Sol-Ark.