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Error 11 - Relay Test Fault - Installation error or possibly relay failure
Error 11 indicates a failed automatic self-test of the MultiPlus-II or EasySolar-II relays. It is often a result of an installation or wiring issue, though it can also be triggered by a hardware failure (eg inoperable relays).
If a grid code is selected in VEConfigure, then the backfeed relays are tested every time before connecting to the mains.
Steps to take:
Step 1: Make sure that the units have been updated to the latest firmware version. There have been various VE.Bus error 11 related improvements in the firmware. This may correct the error, and if it does not, it will provide additional information to assist troubleshooting.
Step 2: Verify that system is properly wired to your installation and your local codes. Remember to check the earth connection on the unit AC input. Earth should be grounded according to your local grid rules. Do not connect Earth to Neutral in the unit itself. This will create a safety hazard and may prevent RCD devices from working. Contact another licensed electrician if in doubt.
Step 3: Disconnect the L and N wiring from the ACout terminals on each inverter/charger. Which, in case of a parallel or three phase system, isolates the ACout connections for each unit. If the system then starts normally there might be a problem with a connected load (e.g. a leakage between load, neutral and ground).
Step 4: Check your Neutral-out connection. In most cases there should be no external connection between ACin-Neutral to ACout-Neutral, or to Earth.
In Australia, using grid code AS4777.2:2015, it may be mandatory to make an external connection between Neutral-in and Neutral-out. Select either design configuration in the grid code section while programming the MultiPlus-II with firmware 466 or above.

After configuration, always confirm that the system is safe with routine electrical safety checks in both modes (eg test RCD operation with AC input connected and disconnected).
Step 5: Neutral and line input might be inverted. Check the input connections, swap them if needed and retry. In this case, “Failing step: 8” will show.
Detailed diagnosis of Error 11
After updating your VE.Bus inverter/charger to firmware 454 or higher; and running Venus OS v2.23 or later, a detailed VE.Bus Error 11 report is available in the GX device menu, under MultiPlus → Alarm Status → VE.Bus Error 11 report.
Examples of information in the GX Device menus:
The information shown is:
- A six digit number; which contains all the details
- An error ID (#4 in above screenshot). Note that this does not count the number of VE.Bus errors; its just a unique ID that can help recognizing that a new error has occurred.
- Flags
- The failed step; it counts backwards: step 9 → 8 → 7 and so forth.
Common causes:
- Failing step #8: check that line and neutral have not been swapped. Unlike non-grid code installations; line and neutral need to be wired correctly.
- AC0/AC1 mismatch and UMains error: this is fixed in VE.Bus inverter/charger firmware version 455.
Other shown error details, listed below, are not related to any known installation issue and can be caused by a faulty unit or configuration issue. In any case, also when one of below errors shows, make sure to go through all the above steps for any error 11 issue.
- Failing steps #2-7.
- AC0 /AC1 mismatch.
- Communication error.
- UMains mismatch.
- Period Time mismatch.
- Drive of BF relay mismatch.
Unable to solve?
When the error persists after the all above steps, or when any other Failed step or extra explanation shows, then the unit may be faulty. Follow the support procedure and contact your dealer. Make sure to document full system wiring in a diagram, all steps and tests taken to diagnose and rule out installation error, and provide a photo of the error details shown on the GX Device menu.
Recovery: auto-restart once the error is gone.