In this special edition of Contractors Corner, the manufacturer of lithium batteries for private households and businesses, Fortress Power, shows the importance of correctly dimensioning a solar battery. Below is a portion of the company's Solar Spotlight podcast with Solar Power World. However, listen to the full episode here or on your favorite podcast app to make sure the systems are built for maximum life.
Where should contractors start when dimensioning a battery?
When we talk about battery storage, we need to categorize the different uses so that I can start with a backup or off-grid system. For backup and off-grid, what type of appliance you want to back up during a power outage is really important as it will determine what you want to place on the backup bay.
After that, you want to determine the autonomy – e.g. B. I want to be backed up for one day, two days, three days. And then look at the solar PV system as well, as this will determine how quickly your battery bank can be charged.
For customers who do not have a net measurement or whose electricity price is so high that it makes no sense for them to feed solar power into the grid, it is essential to take into account the size of your PV system and your daily consumption. Ideally, the battery should be charged during the day and supplied with power at night. You want to have this full cycle.
Then you determine the optimal size of the battery bank. You do not want to oversize or undersize, because you want to achieve the best profitability for the customers.
You will also want to set the battery life for lithium to around 80 to 90%. Lithium batteries can discharge you completely, but each time you discharge the battery completely, you shorten the life of the battery. For this reason, we recommend that you as the manufacturer use a depth of discharge of 80 or 90% in order to achieve a longer duration.
Why is the size of the battery important?
The dimensioning of the battery is so important for the longevity of the devices. You want the equipment that you buy and invest in to work the way they are supposed to. First and foremost, the sizing of the batteries ensures that the devices you buy do what you want them to do. There will be fewer bugs later, less trouble, fewer people coming to provide technical support for your system.
Sizing is very important as it will be a good foundation for the rest of your project. You don't want to go to all these efforts to set up an energy storage system and solar with an inverter and then at one point you turn on too many devices at the same time as this will turn off the battery based inverter and ultimately the energy storage system will turn off. This is most likely a safety feature of the battery, but it is another point why we want to properly size the battery and properly size the critical load table to avoid unexpected shutdowns and expected shutdowns due to it – or oversizing.
Are there any tools that contractors can use to size batteries?
We actually developed a sizing tool for our authorized dealers. It will help you sizing the essential load field, basically figuring out the size of the battery bank that can meet customer expectations.
Be creative and use various options to determine the size of your battery. Then, if you'd like to run it through Fortress Power, please email sales@fortresspower.com which is monitored every day and can help you plan a project whether you are a homeowner or a solar contractor. It's definitely good to have extra eyes, especially when sizing a battery that is still relatively new, like it was when sizing solar power 10 or 15 years ago.
This podcast is sponsored by Fortress Power