Issues with electrical wiring when retrofitting a battery energy storage system

Most people that are looking at installing an energy storage system (battery and battery inverter) don’t realise that every installation is different and there is no one size fits all. Installations are very dependent on whether there is already solar PV in place and the current electrical wiring situation at the premises.

When you decide to connect a battery energy storage system to your already installed solar panels there are things that need to be considered that may not become apparent until the actual installation is to take place. These may make installing the battery system much more difficult, costly and time consuming but actually has nothing to do with the actual battery system itself.

When a house is built an electrician will have wired the house and hopefully the wiring meets current electrical standards at the time. However, electrical standards change over time and older houses may not have electrical wiring that meets current standards. Also, particularly with older houses wiring may become damaged or wear out over time.

As houses change hands different people may decide to add their own touches and may employ electricians to make changes to the electrical wiring. When an electrician is called in to make changes to existing electrical wiring, they are more likely to only make changes that suit the job they are being employed to do and may not take into account the effect their changes may have on the existing electrical wiring or may not point out to a householder that their electrical switchboard may need upgrading to bring it up to electrical standards. Of course, an electrician may point out to a householder that their switchboard needs upgrading but that householder may not wish to go to the expense of upgrading wiring or switchboards when there is not an apparent critical need.

Householders may then decide to install solar panels on their roof. Solar installers have various degrees of experience and reliability and solar systems are often sold at the cheapest price possible. Usually, if you pay a minimum price for your solar panel installation you are more likely to have cheaper quality, less reliable components installed and the minimum amount of electrical wiring to make the system functional.

Of course, there are many honest and reliable solar installers and electricians around who will install your solar panels correctly but generally they will be more expensive as they will be using quality equipment and upgrading switchboards if needed.

This can mean that when the solar installer wires up the solar system and finds the switchboard really needs upgrading rather than doing the upgrade (which would add to the cost of the solar system) they only connect the solar panels to one circuit of the house. This may mean that the solar system is really not very useful in supplying power to the household. We have even seen solar systems that have only been connected to the lights and as generally lights are not used when the sun is shining is not really a good use of a 5 KW solar system.

The last in line of electricians is then the battery installer. Most battery systems allow you to monitor them and what they are doing (although not all battery systems allow this). This means it is easier to understand if your battery system isn’t working correctly.

Battery systems can be set up in various ways, either to handle all loads in the house or only to handle specific circuits. They can also be wired to continue to supply power when the grid goes off, again either to handle all loads in the house or only to handle specific circuits. This is particularly relevant if you have very energy hungry appliances like air conditioners and induction cooktops.

Not all batteries have the capability of being set up with all these options. Some batteries must be connected to the grid at all times and some battery systems have limited inverter capacity which means they are limited in the number of appliances that can be utilised at any one time. Any ethical battery installer will discuss these different options with the client.

All these variations have different ramifications on the wiring needed.

This means the battery installer may have to do a major rewire of the house wiring before installing a particular battery system. This is nothing to do with the battery itself but to do with a client’s requirements for the battery system as well as previous household wiring setup.

These are just some of the questions you need to think about when installing a battery energy storage system and are really about making sure the battery system is designed for your needs. If you aren’t asked these questions you need to ask if the salesman / installer is trying to find out the best system for your needs or just trying to sell you the system they want to sell you.

If you would like to know more about getting a safe, reliable and recyclable battery energy storage system for your own home, business or micro-grid to increase your energy independence visit us at We have a number of different sized systems that can cater to your budget and household needs.

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