Solar Hybrid Systems; an overview

What is a Solar Hybrid System?

You may think that a Solar Hybrid system is just a Solar system with batteries, but it’s much more than that. Kunini has been installing Solar PV systems since 2010 and did install some early versions of Solar hybrid systems. Back then, these were off-grid systems that were a bit iffy, to be honest. The Solar inverter was an off-grid type, and the batteries were either lead acid or Solar gel, and you needed to integrate a charge controller for the batteries.

You needed so much kit to get them working, and reliability and maintenance were tedious. Those systems were defiantly hit and miss!

Move forward a few years, say 2018 or thereabouts, and real Solar Hybrid systems started hitting the market. Kunini started installing Solar Hybrids with Lithium batteries around 2018.

So, what is a Solar Hybrid System? It’s a Solar PV System with batteries that can be used for emergency power or to save energy at night.

Growatt Hybrid System 20kW

Can a Solar Hybrid System take care of all my power needs? Yes and no. It all comes down to requirements and design. Let’s look at the components of a Solar Hybrid System. 

Solar Hybrid Inverter – the brains behind the system with an integrated solar battery charger and other intelligent components. The Hybrid Inverter can be single or three-phase. Typically, 5 or 10kW, but some bigger ones are in the pipeline. If you have a single-phase supply, the only size available is 5kW. If you have a three-phase supply, you can get a 5 or 10kw inverter.

What does that mean? 5kW will give a 500W output, and a 10kW inverter will provide you with a 10000W output. Note: the three-phase inverter backup output needs to be balanced; generally, 3.3kW per phase and no phase imbalance of more than 1kW.

So, is running your whole house from Solar PV and Batteries possible? Yes, but it is costly. New commercial Solar Inverters or Smart Energy Systems are available for small commercial or luxury residential systems. Still, these start around 30kW, and you need sufficient battery storage systems and larger Solar PV arrays to charge them.    

Lithium Batteries and Controller – batteries have come a long way these past few years, and new technologies are constantly being researched.  Right now, let’s look at Lithium. Lithium batteries are an excellent choice for solar power systems. They are incredibly forgiving when it comes to the level of discharge they will tolerate. Said another way, you can safely go up to a 100% depth of discharge (DoD) while maintaining nearly 98% efficiency.

Many Solar Hybrid manufacturers have their own batteries and controllers.

Smart Logger / Smart Meter – These smart meters are used to control Solar Production, Load Consumption and Zero Export Control. These work by installing CT clamps on the main incoming power cables and connecting the meter to the Solar Inverter via an RS485 cable connection.

Design & Installation – when choosing to install a Solar Hybrid system, you need to decide what your needs are. Emergency backup power? Energy-saving (using batteries at nighttime)? Whatever your needs are, selecting the suitable loads to add to your system is critical. If it is for emergency power, then look at critical loads; lighting, power, refrigeration, house water pump, internet etc. If it is for Energy Saving, then the loads are equally crucial as only the loads connected to the Hybrid Inverter’s backup box will be able to receive battery power. What loads are not advised to be on the battery system? Large Air-condition units, Hot Water units, Ovens, Pool Pumps etc.

Common Misconceptions I have a Solar Hybrid system; if there is a power outage, will this cover all of my home power needs? No. Only the loads connected to the battery system, as explained earlier. Why? Because if you feed the Solar Energy directly to your loads through the Solar Inverter, you will be pushing power down the utility power lines, which is not allowed. When there is a power outage, the Solar Hybrid Inverter switches to battery mode or off-grid mode. It’s the batteries that supply the power needed for the loads inside your battery backup box.


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