Monitoring

How do I know how much solar energy my home is generating and using?

The Tesla app gives you real-time and historical visibility into your solar production and home energy usage.

What peak power output should I expect to see from my system?

At the moment when midday sun is shining, typical peak AC (alternating current) power output is 70-80% of a system’s DC (direct current) rated capacity. Many environmental factors impact the instantaneous power output of the system including time of year, time of day, weather, shade, atmospheric conditions and temperature.

How can I ensure my system is working well?

System performance is measured in how many kilowatt-hours (kWh) it produces over a given period of time. A simple way to tell if the system is performing as expected is to utilize the “Daily kWh Rule-Of-Thumb” method below:

1. DC SYSTEM SIZE: Gather your DC (direct current) system size from your system designs or under "System Description" on your contract.

2. SEASONALITY FACTOR: Systems perform differently based on the time of year and so the production estimate will vary throughout the year. Seasonality Factors are based on the knowledge that the longest day of the year is June 21st and the shortest December 21st. Use the Seasonality Factor listed below:

• "Summer" (May, Jun, Jul): 5 to 7
• "Fall" (Aug, Sep, Oct) or "Spring" (Feb, Mar, Apr): 3 to 5
• "Winter" (Nov, Dec, Jan): 1 to 3

3. CALCULATE ENERGY PRODUCTION ESTIMATE: Estimated daily kWh system production= DC System Size X Seasonality Factor

4. ACTUAL ENERGY PRODUCTION: In your Tesla app, review the actual daily solar energy production for a recent full day. It's best to use a day where the cloud cover percentage is near zero.

5. ANALYZE: Compare the estimate you calculated, to the actual production. If the Actual is equal to or greater than the Estimate, then the system is performing as expected. If the Actual is less than the estimated, look to see whether shading or weather are a factor and if the low performance is consistent from day to day. Note that in the winter months performance for some systems may be near zero due to a combination of shading and weather.

Example: You have a 6 kW (DC) solar system. The estimated daily production for your system by season would be:

• Summer (May, Jun, Jul): 30-42 kWh/day
• Fall (Aug, Sep, Oct) or Spring (Feb, Mar, Apr): 18-30 kWh/day
• Winter (Nov, Dec, Jan): 6–18 kWh/day

On June 3rd, the system produced 38 kWh. This is in line with the estimated daily production range for June (30-42 kWh/day). Based on this, the system is performing within expectations.

How can I tell that the Tesla Gateway is working correctly?

First, look at the Tesla Gateway (the box connected to your internet modem/router). Under normal operating conditions each light should be doing the following:

• The POWER light should be on.
• The DEVICE light should blink (briefly) once every five seconds per device with which it is communicating. For example, a customer with two inverters, should see two blinks in a row, then a pause, then the pattern repeating. At night, when the inverter is off, it is common for the device light to be off.
• The WIRELESS light should be blinking constantly.
• The ERROR light should be off. If your system is interconnected to the grid you should also be able to view your system production on your monitoring page.
• If the ERROR light is off, yet you are receiving a Gateway offline message, it is possible that the Gateway needs to be reset. To reset the Gateway unplug the black power cable on the back of the Gateway, wait 20 seconds and plug it back in.