SOLAR BATTERY SIZEHOW MANY DO YOU NEED?
CHOOSING THE RIGHT BATTERY SIZE
The optimal battery size for your needs is determined by:
Your motivation for installing a battery
Your power consumption
Your financial situation
Size of your panel array (new or existing)
What is your motivation?
In the intention of saving money, most people purchase a battery to try to remove the electricity they purchase from the grid. Some may choose a battery for backup power, whereas others may prefer to use solar energy to power their home.
If your goal is to save money, you should still plan on purchasing some electricity from the grid at specific periods of the year. It is not cost effective to size a battery to effectively take you off the grid.
Use of electricity
Each day, the average Australian family consumes 16kWh of power. A typical household may consume one-third of its electricity (5.33 kWh) during the day while solar panels are producing electricity, while the remaining two-thirds (10.67 kWh) is purchased from the grid. If you want to utilize a battery to power the electricity you buy from the grid, you’ll need one with at least 10kWh of capacity.
What are you willing to spend for a battery?
There aren’t many batteries available that are a suitable size for your electricity demand if you aren’t willing to pay more than $10,000 for a battery storage system. Solar batteries cost around $1,000 par kWh, with a 10kWh battery costing around $10,000.
If you use very little energy, you could get by with a little battery smaller than 5kWh.
Creating a new system or expanding an existing one
Purchasing a battery is considerably more cost effective when purchasing a new panel and battery system compared than adding storage to an existing system. The processes for calculating your battery size vary depending on whether you currently have solar panels or are planning to purchase a solar plus battery combination.
HOW TO COMPUTE
BATTERY TYPE
The calculation for battery size differs based on whether you are:
Purchasing a new solar panel and battery system
Alternativement, you may already have solar panels.
Calculator for solar and battery size
Our solar panel and battery size calculator will tell you how many panels and batteries you require. All you need to know is your average daily electricity consumption and when you use it, and the calculator will compute the rest.
For current solar panel owners
Our solar battery storage calculator allows you to experiment with different battery sizes to see how they affect payback and savings. For existing solar owners, this is the ideal way to size a battery because the financials determine what size you need based on your electricity usage habits.
FOR BATTERY SIZE
A SYSTEM OF 5 kW
Regardless, if you already have a 5kW system or are considering purchasing one, you will most certainly want a battery with a capacity of at least 10kWh, preferably up to 13.5kWh. The exact battery size you require is determined by how much electricity you regularly consume during daytime hours as well as your purchasing motivations.
Why do you need a 13kWh battery for a 5kW system?
Depending on where you live in Australia, a 5kW solar power system will normally produce between 17 et 21 kWh per day. For most consumers, around two-thirds of a system’s output is sent back into the grid, which is approximately 13 kWh each day. This 13kWh could be used to store your solar electricity in a battery instead.
If you consume more than half of your electricity during the day, around half of the output will be routed back to the grid, allowing you to charge a somewhat smaller battery, more like 10 kWh.
Batteries suitable for 5kW systems
Because of the popularity of system sizes between 5kW and 6.6kW, some of the best solar batteries are designed to support these systems. Both the LG Chem and Tesla Powerwall II batteries are appropriate for a 5kW installation.
