Sol-Ark 15K / 12K Fault F13, F18 & F20 (Grid Mode Changed / Overcurrent / DC Bus): Complete Fix
Sol-Ark 15K touch screen logs Fault F13 (Grid Mode Changed), F18 (AC Overcurrent Hardware), or F20 (DC Overcurrent Hardware) and clicks its internal transfer relays.
Safe Parameter & CT Check
🔬 Root Cause Electrical Physics
F13 is an informational reset when grid parameters or CT settings are changed. F18 and F20 occur when instantaneous AC or DC current exceeds the 275A/300A IGBT hardware protection threshold—most often triggered by (1) an un-soft-started 5-ton AC compressor, (2) a shorted appliance on the Load breaker, or (3) reversed/loose CT sensor leads causing the inverter control loop to oscillate.
⚡ Step-by-Step Multimeter & Diagnostic Test Procedure
Navigate to the Sol-Ark touch screen -> Home Icon -> Gear Icon -> Battery Setup and verify "Max A Charge" and "Max A Discharge" match your battery bank BMS limits (275A max on Sol-Ark 15K).
Check the Dial/Status screen for L1 and L2 CT watt readings: if one leg shows a negative (-) sign during normal grid import, your CT clamp arrow is pointing the wrong way!
🛠️ Safe DIY Reset & Remediation Steps
- 1.Verify both L1 and L2 CT clamps are snapped completely shut around the utility service entrance conductors with the arrow pointing TOWARD THE INVERTER / HOME LOADS (away from the utility meter).
- 2.Never extend Sol-Ark CT wires with unshielded thermostat wire—use only twisted-pair shielded Cat6 cable.
- 3.Perform a full cold boot: Turn off AC Grid breaker, turn off Load breaker, turn off PV switch, turn off Battery breaker, wait 5 minutes until the LCD screen goes completely black, then power up Battery -> PV -> Grid -> Load.
👷 When to Escalate to a Licensed Solar Electrician
If F18 or F20 recurs immediately upon turning on the Battery breaker with all AC loads disconnected, an internal IGBT bridge module has shorted and requires Sol-Ark 10-year warranty RMA.
🔋 Direct Replacement & Upgrade Hardware
Compare Sol-Ark 15K against the EG4 18kPV (/go/eg4) in our head-to-head engineering battle.
Frequently Asked Questions: Sol-Ark 15K Fault F13 / F18 / F20 Fix
Is Sol-Ark Fault F13 an actual hardware breakdown?
No! Fault F13 ("Grid Mode Changed") simply means the inverter re-initialized its grid synchronization profile after a firmware update, a voltage/frequency parameter change, or a grid brownout recovery.