Hybrid Solar Inverters
What is a hybrid solar inverter?
A Hybrid PV solar inverter can deliver power during either on-grid or off-grid conditions. The grid-connected systems have solar panels for utility savings, and a battery for backup power and peace of mind. Never be without power when you get energy from the Sun, the utility company or the batteries.
Both the PV array and the utility power can keep the batteries charged. In the event of a utility outage, the batteries deliver electricity to the household for normal, everyday use. If the utility is down for many days, don't worry, the solar panels will generate electricity for the home and charge the batteries.
Types of Hybrid Solar Inverters
As the solar industry has evolved, most modern solar inverters have hybrid capability. Some inverters are "MILD HYBRID" because they require additional components to work off-grid. The more popular are "ALL-IN-ONE" hybrid inverters that do not require additional components.
Mild-hybrid inverters are not intended for full off-grid capability, while all-in-one inverters generally can operate entirely off-grid, and with higher output capacity. Both types can also connect with a fuel generator for another layer of backup.
The additional components required by mild-hybrid inverters are commonly called a "controller" or "backup interface" or "gateway" or "backup start". In simple terms, this component provides the auto-transfer capability to create a local "micro-grid" for backup operation. This component requires additional costs and wiring. Popular brands of the mild-hybrid type include Enphase microinverters, SolarEdge Home Hub, Canadian EP Cube, SMA Smart Energy, Fronius Gen24, Tesla, Franklin, GoodWe, Growatt, or Solis.
The mild-hybrid inverters usually have a smaller AC output rating as they are intended for partial-home backup. However, they are modular, so multiple inverters can be added to achieve higher AC output needed for whole-home backup.
In the case of all-in-one hybrid inverters, the micro-grid capability and auto-transfer switch are integrated with the inverter. No additional wiring or hardware costs are necessary. In addition, these all-in-one hybrid inverters generally have higher AC output and surge capability, often with 200A pass-through rating, to power an entire house for whole-home backup. Popular brands of this type include Sol-Ark, EG4, Fortress or LuxPower.
Both types of hybrid inverters can work with DC connected solar panels, especially for new systems. They can also work with AC-coupled solar panels to integrate with existing, older solar arrays.
Battery Compatibility with Hybrid Inverters
The mild-hybrid inverters often work with specific batteries from either the inverter manufacturer or a third-party battery manufacturer. The batteries typically operate at higher DC voltage around 400 volts.
For example, the Enphase system only works with Enphase batteries. The SMA Smart Energy inverters only work with BYD batteries. The SolarEdge Home Hub inverters only work with SolarEdge batteries or the LG Chem RESU Prime batteries. High voltage batteries are generally more expensive, and have a 10 year warranty with a longer lifespan or "cycle" life.
In contrast, the All-In-One hybrid inverters are battery independent. They can work with most any low voltage battery that operates at 48 volts DC. Because there are many suppliers of low voltage 48V batteries, they generally are a better value. Most offer a 10 year warranty, with lifespan ranging from 6,000 to 10,000 cycles, or 16 years to 27 years.