Northwest homeowners primarily install a Tesla Powerwall battery backup system to power their homes in the event of an outage.
While power outages have increased in recent years due to more severe weather-related events and outdated utility infrastructure, homeowners and businesses can turn to solar plus a Tesla home battery to keep the lights stay on when the grid goes down.
Can solar panels power a house during a power outage?
It’s important to remember that your solar panels alone will not power your home in the event of a power outage unless you have a home battery backup system installed, like the Tesla home battery. This is by design to prevent energy from being sent to the grid where line workers are trying to restore power. Line workers cannot safely restore power to the grid if a home’s solar panel is actively supplying energy to the grid via net metering.
How does a Tesla battery backup system work in a power outage?
A storm rolls through a neighborhood knocking out power. Homes go dark. The sound of the whistling wind is replaced by the incessant rumble of a few gas-powered generators. In some windows, the faint flickering of candles can be seen. However, for a homeowner with Tesla Powerwall, life goes on exactly as before.
As soon as a power outage occurs, your Tesla Backup Gateway instantly disconnects from the utility grid and Powerwalls delivers power to your home in a fraction of a second. In fact, the switch is so instantaneous that you might not even know you lost power. A quick glance at your monitoring system indicates the Powerwall is supplying your home with energy. Appliances, lights, internet, and TV can continue uninterrupted.
Before your Tesla battery backup system is installed, you’ll have to make some important decisions.
Budget, for one. The more Powerwalls you stack (you can have up to 10), the more of your home you’ll be able to back up.
You will often be able to decide what loads you’ll want to be backed up. Your fridge. Lights. Internet. The more that you choose to back up, the more Powerwalls you’ll need and the more energy you’ll consume.
Your Tesla Powerwall certified installer will separate these loads so that only these will draw on your Powerwalls during an outage. The rest of your home will remain without power.
How long does Tesla battery backup last in a power outage depends on your energy usage, the size of your solar energy system, and what time of year it is. As you might have guessed, an outage during a long, sunny Northwest summer day means that the solar panels will be producing much more energy than during a winter storm.
How many Powerwalls do I need?
In many cases, each Powerwall will provide 4-8 hrs of backup in a power outage, and while most homeowners decide to install two Powerwalls, that time increases to between 8 and 16 hours. However, if you’re connected to a solar energy system this time increases, as your solar panels will continue to charge your battery backup system.
One day, we might be able to store enough energy to get us through long outages without making any sacrifices, but the technology isn’t there yet. For now, the best practice is to limit your backup loads so that your essentials can run for as long as possible on a single charge.
Tesla home battery low energy operations
While in standby mode, and paired with a solar energy system, Powerwall will automatically attempt to recharge from your solar system every hour between 8 AM and 4 PM local time. However, if your solar system can provide sufficient energy to charge your Powerwall and your home, then recharging from your solar system will continue. If for some reason your Powerwall’s remaining energy decreases by more than 2.5%, then it will become inactive and wait for the next hour to attempt charging again.