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.
Having all the key features for solar and battery storage in one simple plug-and-play inverter means hybrid inverters are generally much lower cost and easier to install compared to more complex battery storage systems which often require multiple inverters. However, they do have several limitations and are generally not recommended to be used for off-grid solar systems.
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 Ingeteam and Sol-Ark.
Hybrid inverters are a very affordable choice for average households who want to be more self-sufficient using solar and batteries but don't intend on disconnecting from the grid and do not experience frequent blackouts. Refer to our complete hybrid and battery storage review for a direct comparison of the various hybrid inverters and battery storage systems.
To function as a backup power supply, a hybrid inverter must be able to isolate from the grid during a blackout and use the battery power to back up the household essential circuits**. Most modern hybrid inverters have the ‘grid isolation’ feature built-in but some hybrid inverters do not which means they cannot operate in either backup or off-grid mode. However, often an additional backup-box or EPS (emergency power supply) is available as an add-on 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 are recommended for off-grid solar systems due to the high continuous and surge power ratings.
**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 inverters or an off-grid system.
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, often referred to as multi-mode inverters, are much more powerful inverters that can typically 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.
Read more about the best off-grid inverters and systems here .