EG4 › Problems
EG4 solar production is low, drops off, or a PV input reads zero
Your EG4 system makes less solar power than it should, production drops off, or a PV input reads zero. 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 |
|---|---|
| W027: Battery open fault (FlexBOSS21) | The FlexBOSS21's internal DC-DC converter board has failed and disconnected the inverter from the battery. It does not recover on its own. Grid power to the loads and PV production still work. |
| E017 | Internal communication fault 2. |
What to check first
- In the app or on the screen, look at each PV input's voltage and watts and compare the inputs with each other.
- On a 12000XP whose PV input reads near 120 volts in the morning, ask your installer to open and reclose the PV disconnect, and note whether the voltage and watts go back to normal.
- On a FlexBOSS21 that takes no PV at all, check that the side power switch is fully in the on position.
- In the app, look at the working mode and priority settings, such as Charge Last, Battery Priority Start time and Weather Optimizer, and note what they are set to.
- If a FlexBOSS21 shows W027: Battery open fault, contact EG4 support with the inverter's serial number.
- If an input stays low after these checks, it needs a technician to measure the string voltages at the panels and at the inverter.
Safety. A bad PV connection can overheat and melt a terminal block or a combiner box, and the breaker on that circuit may never trip.
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.