With the advent of microinverters, people are on the lookout for hybrid solar systems that can work with batteries. In fact, there are companies that have already launched microinverter battery backup systems into the market. So if you are wondering if microinverters can team up with batteries, the short answer is yes!
However, the process is a bit complicated and technical. Let’s find out how the two work with each other!
Microinverters can definitely work with battery backups. You just have to employ a method known as “AC Coupling,” in which an AC battery inverter is used to link the batteries straight to the switchboard’s 240V AC.
The ability to divide the power flow between the grid and the backup system with microinverters is one benefit of employing the AC-coupled system. The size of the storage capacity can be adjusted with the use of microinverters.
For example, certain branch circuits can only connect to the main panel, while others can link to the sub-panel that the battery inverter supplies. The complete array is qualified for net metering credits even when parts of the microinverters are linked to the battery. However, because they are segregated from the essential loads’ panel, which is powered by the battery inverter, the microinverters attached to the main panel will stop producing if the grid goes down.
The battery inverter must be sized for the maximum AC output from the PV system that is connected to the essential loads’ panel. You need to ensure that the battery inverter system can handle the entire array’s AC output. Remember to choose a number of microinverters for these systems that are equal to or less than the kW capacity of the battery inverter. Then, place the remaining microinverters on the main panel.
To understand the working of AC coupling, let’s first understand some fundamentals.
The primary difference between Grid Connected and Off-Grid solar power systems is that off-grid systems need to store the energy in batteries.
Historically, a regulator was the main tool used to control overcharging. It absorbs DC power from the energy source, analyzes how the battery is responding, and makes necessary adjustments.
If the system has a 240V AC energy source, a battery charger is often used, which serves the same purpose but in a slightly different method.
When the batteries are fully charged in either scenario, the regulator or charger will stop providing energy.
If you have Direct Current (DC) equipment, you can use the energy once it is stored in the batteries. However, in most situations, an inverter transforms the DC power to 240V AC, just like the main power.
Inverter manufacturers realized many years ago that it made sense to combine these into a single unit and created the off-grid inverter. These were often made to accept a range of inputs and outputs, including AC input from generators, DC input from batteries, etc. Generally, a regulator was still used to link the batteries to solar panels and other equipment.
Although it took some time, manufacturers discovered that they could use grid-tied inverters to convert the solar input to AC, which led to the creation of AC Coupling to simplify things.
Management, monitoring, and efficiency were optimized by mounting everything on an AC Bus, excluding the battery. Transmission losses were minimized, cable sizes were lowered, and flexibility was increased despite an increase in electronics cost.
So, what is the actual working process of this type of system?
In this kind of system, branch circuits are merged at a gateway combiner box while microinverters are connected to the modules. They are then supplied to a panel for important loads that is also wired to a battery inverter. This battery inverter is in charge of controlling the energy flow to the batteries and, in the event of a failure, simulating the grid’s frequency to maintain PV production.
In order to isolate the essential loads’ panel from the grid and to separate from the grid input when the grid goes down, the battery inverter uses an internal contactor.
You can set up the system to include an external ATS on the grid side of the MSP to directly power the main service panel.
From a safety standpoint, grid-connect inverters constantly look for a 240V AC reference source and are built to shut down if it’s not available. Thus, in a non-mains connected AC coupled system, a reference point must be established in order to deceive the Grid Connect inverters into thinking that the current is real.
The inverter charger can accomplish this by generating 240V AC from the battery or by using additional sources (such as a generator) if they are available. In any case, as you could expect, this requires some rather complex controls to be done securely and consistently.
If the inverter and battery are large enough to carry all the loads and surge loads on the MSP, it may be unnecessary to use a separate critical loads panel. When a customer wants to power the main service panel, an external ATS is necessary; however, this comes at an additional cost and with more complexity.
Therefore, logically speaking, these kinds of systems can be connected with microinverters that offer solar as an AC source. All of your AC solar panels only require a simple solar panel and grid tie inverter swap. You won’t be left in the dark if you get a microinverter-based system because all you’ll need is an AC-linked system if you decide to add batteries in the future.
Microinverters can team up with batteries using AC coupling technology. If you are seeking a reliable and trustworthy company to get bulk microinverters, you should contact Beny today! They will help you get the best solutions for your business.