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  Solar & Renewable Energy Specialists.  
Specializing in Grid Connect, Solar Hybrid, Standalone Systems and Emerging Technologies.

Hybrid Solar System

 

A Solar Hybrid system is simply a Grid Connect System with the added benefit of a Controller and batteries.

 
Some households like the added benefit of a Generator and in some location a turbine can also be included. With a grid connect system the surplus power is sent out to the grid but with the Solar Hybrid System the surplus power is sent to the batteries to be used either at night or in the event of grid failure or when the grid is unstable or not able to supply enough power. The master controller is the brains of the Solar Hybrid System. It is responsible for directing power to the areas where it is required. During the day the power that has been produced by the panels and converted from DC to AC by the Inverter, will typically be used by the house, any surplus power is sent to the Batteries. At times when there is a blackout and the panels are not able to produce enough power to supply the house and able to keep the batteries topped up to the level required, the controller will ensure that the Generator and or turbine sends power they create to the areas where it is needed the most.


 Understanding the benefits of a Solar Hybrid System can be as complex as understanding the reasons why a customer will want to consider purchasing one. For example has the home owner applied for to the Network provider for a large grid connect system, let’s say 5kW because they use a lot of power during the day, but has only been approved for a smaller 2kW system by the network provider? Because the area is saturated with Solar Systems and they are concerned about the amount of power going back to the grid.

A Solar Hybrid System can be installed greater than the 2kW but can be configured to ensure that never more than the approved 2kWs will go back to the grid.  They would install the 5kW Solar Hybrid System which will cover the house loads during the day. In the event that nobody is home during the day and because the Solar Hybrid System has been correctly configured any surplus power will be stored into the batteries to be used during the night or the Solar Hybrid System or simply wound down if the Batteries are full.

Another benefit of a Solar Hybrid System is if the customer is a heavy user of Electricity at night and only a small portion is used during the day. A standard grid connect system would not be suited to this household as it would only cover small percentage of the power bill and the selling of any excess power to the grid at a rate far less than it is purchased for does not make economic sense. A Solar Hybrid System can be installed to cover the minimum daytime usage with the bulk of the power to be sent directly to the batteries, ready to be used at night as required. If sized correctly can eliminate most if not all of the bill, depending on the time of year. The benefits will continue to increase as the cost of power rises.

If you are looking at purchasing a Solar Hybrid System it is very important that understand how your household uses Electricity and that the company you are in discussions with takes the time and effort to understand how your household uses it. That way it is designed and installed correctly with no nasty surprises 9-12 months later.

The batteries are a very important component of the Solar Hybrid System, they can also be the most expensive part of the System. Often if the price of the system is greater than a client has anticipated, some clients may simply look at reducing the batteries size and or quality of the battery bank, which may seem be the easiest way to save on the overall cost. Which may seem to be a good option if they are not made aware of the potential consequences this may have.

Trying to understand a little of how batteries work can save you years of headaches down the track.

We will try to explain a few things you may need to be aware of when trying to choose the best battery solution for your Solar Hybrid System.  You don’t need to be technically minded to know the workings of batteries, but some of the basics will definitely help.
Looking at the graph below is the type of graph you may come across on a battery specification sheet. Running down the side is Cycles in most this case 1 cycle represents 1 day. Along the bottom is depth of discharge or DOD in %. Simply the more power that is drawn out of the battery the shorter time period you can expect the battery will last.

 So from the top of the graph the DOD is 10% the battery will last 12000 cycles and each cycle is a day the battery will last approximately 32 years.

Innolec Solar Power Graph 5.0
 
Which may not be a practical solution as it will be a huge bank and cost a fortune. If we look at DOD 30% & approximate 5000 cycles works out at over 13.5 years. A more practical solution.

If we go DOD 80% roughly 1500 cycles, the battery bank will last 4.1 years, again not a practical option. In most cases a DOD 30 – 50% is a practical solution, but that will depend on the clients needs. Do you want to save money initially but have to replace the batteries every 3-5 years or pay a fortune and maybe not have to replace the batteries while in the home.

Below is a chart which shows cycles along the bottom and along the side extracted capacity % is used instead of DOD %.

DOD% is the most common term used on Battery specification sheets.

Innolec Solar Power Graph 6.0
 
In practical terms the better quality Batteries will have a greater number of Cycles. The poorer quality Batteries will cycle less or may not even display or mention Cycles and DOD%.

Also when trying to determine the size of the battery bank that you may need, you will need to consider the physical size of the batteries and how many you require, which in turn will lead to what potential area that is available for the bank to be located.