Battery storage is one of the most important aspects of the solar power system. Many people are asking about battery storage so it is important to understand the technology and the role batteries play in the system.

 

Battery storage will allow you to do the following:

The main purpose of batteries is to store excess power produced during daylight hours for use in the evening.

Batteries can provide backup in case of a power outage.

You can also use them to reduce your bills by manipulating the time of use tariffs (TOU) so when you have to purchase power, you can do it at the cheaper rate when rates are lower.

They will enable you to sell power back into the grid at premium rates

 

The financial benefits of battery storage

Unlike solar power and related technologies, currently battery systems will not give you sufficient financial savings to consider them as a financial benefit.

For example a system that stores 6 kWh of additional solar energy produced during the days, and assuming perfect utilisation which rarely happens, you will only save around $400 per annum. The batter capacity will also reduce over time, faster than the solar panels.

As the technology improves and the market grows, prices are coming down so the could well be a more feasible solution on the future.

If you have a large system capable of producing significantly more power then you need and you are able to sell this back to the grid at premium prices than it might be a worthwhile investment.

 

Adding batteries to an existing system

All that is required is the battery/batteries, a battery inverter and a metering device.

Batteries store power in DC, not AC so a battery inverter functions differently to a solar inverter. The batter inverter will convert DC power into AC power that your home can utilise.

Provided you’re not manipulating TOU tariffs or are looking to sell power back at peak times, the best time to store power is when you’re producing excess. The best

The function of the metering unit is to determine the most logical and efficient times to store power or to draw power from the battery.

 

Battery compatible, battery ready or backup ready

This can be quite a confusing issue and different people might give you a different answer. The simple answer we provide at Treac is this:

Battery compatible: Any system where batteries can be fitted or retrofitted as explained above. So batteries, battery inverters and metering units would all need to be added. This basically applies to any solar system available. The limitation here is that generally, such a system would not be able to provide battery backup in the case of a power outage.

Battery ready: This is a system that has all necessary components with the exception of the battery. If you wish to move to a battery system, all you would need to do is add the battery. Many hybrid systems are designed in this way.

Backup ready: This is a system that can work with or without batteries but has an Automatic Transfer Switch (ATS) which will automatically supply power in the case of an outage.

A hybrid system does not necessarily provide this functionality so ensure you confirm this.

 

Backup power

Do not assume that a system with a battery will necessarily offer backup power. Additional components are needed and not all inverters or hybrid inverters have this functionality. If you require backup power, ensure this is stipulated upfront and confirm the system is capable of providing backup power.

It would be wise to segregate your load so that in the event of an outage, only essential devices are provided with power and non-essential devices, heaters, air-conditioners, etc., of not used while the system is on backup power. This is to ensure the backup power will last until external power is once again provided or the solar system begins generating enough power for your full requirements.

 

Backup power vs off-grid

Backup power and off-grid power are very different and have different requirements.  Backup power provides short term power to selected appliances for a short duration. A system required to work entirely off-grid will extra components and will have to be designed to handle worst case scenarios such as additional demand during overcast conditions.

For such a system it would be wise to have a back up alternative such as a diesel generator.

Advice if you are considering batteries

As discussed it is probably to soon to see batteries as a financial viable alternative. It might well be in the future so it is an important aspect to consider when evaluation alternatives and selecting a system.

If you do require a complete battery system, Treac are experienced in this and have done many installations so our experts will gladly assist and advise you of the options.