Tesla Powerwall › Problems
Powerwall on backup: solar cuts off early or devices trip
While the house runs on the Powerwalls, the solar shuts off early or won't come back, or UPS units, dimmed lights or solar inverters misbehave or trip. This page covers what the codes mean, what to check first, and the causes behind it.
Error codes that go with this problem
| Code | What it means |
|---|---|
| 18x40: F-L1 Max1 on a SolarEdge inverter | The AC frequency on line 1 is above the SolarEdge inverter's maximum, so the inverter trips. |
What to check first
- Note what misbehaves and when: UPS units going to battery, dimmed LED lights going out, lights flickering while switched off, or solar stopping. Note how full the Powerwalls were at the time.
- Plug a device that fails on its UPS straight into the wall and see whether it works there.
- On a SolarEdge inverter, open Inverter Status in the mySolarEdge app and scan the inverter's QR code to read its fault codes.
- During a real outage or an off-grid test with the main breaker off, read the frequency on a plug-in meter, a UPS that shows frequency, a charger display, or the app's Power Flow screen.
- If solar keeps switching on and off while off grid, check that every Powerwall is working. Turning off part of the solar, such as about half the solar breakers, keeps it within what the Powerwalls can absorb.
- Call Tesla Powerwall support, describe what misbehaves, such as UPS trouble or flickering LEDs, and give the frequency you measured. The request goes to second-tier support and took about a week to ten days.
The causes and the fixes
Partners see the causes behind this problem, most common first, the checks that tell them apart, and the fix for each, with part numbers and recent prices when a part is involved.