Turns out, Derek’s Powerwall whole home battery had silently and seamlessly turned on when the grid went down. He had “no idea.” Life went on normally. Derek, his wife and their children ages six, four and one watched TV, used the internet, lights, appliances, coffee pot… In short, nothing changed during the 36 hours they relied on the Powerwall battery for electricity.
Initially skeptical when the two batteries were installed in the garage (pictured here), Derek’s wife was “ecstatic” to experience how well the Tesla Powerwall System worked.
Throughout the February power outage, Derek monitored the battery levels using the app on his cell phone; they did not go below 78%. How long the Powerwall battery will last during an outage depends partly on the uses in the home. You can make the battery last longer by turning off lights and loads that are not essential, particularly during a long outage. When the Powerwall serves a home with solar, then solar will recharge the battery during daylight. When there is no solar, Powerwall acts as a backup generator and is refilled with power when the grid returns, so you’ll never burn fossil fuels.
Cell phone monitoring shows that the Powerwall is sending electricity to the home (dot moves, but this is a static picture). Screen capture also shows that 83% of the battery remains at 7:26 pm. The grid went down around 4 pm that day.
Cell phone shows that solar is charging the battery during the daytime. Battery level is at 78%.
The grid is back and providing the home with electricity. The Powerwall battery is using electricity from solar and grid to charge back up.
Tesla Powerwall Battery Backup can be added to a home with or without a solar system. But, if the home has solar, then when the Powerwall is installed before 12-31-2019, the owner is eligible for the same Federal Income Tax Credit of 30% as solar. (The federal tax credit is 26% when solar and storage are installed in 2020.)
Northwest Electric and Solar is a Certified Tesla Powerwall Installer.