Portable Power Stations & LiFePO4 Energy Troubleshooting
Pure sine wave inverter overload trips, high-voltage MPPT solar controller faults, BMS temperature protection codes, and battery pack recalibration.
Manufacturers & Brands
OEM hardware vendors indexed under Power Stations
Anker
Manufacturer of Anker systems and diagnostic equipment.
Bluetti
LiFePO4 modular portable power stations and off-grid solar generators.
EcoFlow
Manufacturer of Delta Pro 3, River series portable power stations, and whole-home smart battery panels.
Goal Zero
Goal Zero Yeti PRO 4000 high-capacity LiFePO4 generators, Tank PRO expansion batteries, and high-voltage MPPT solar controllers.
Jackery
Explorer portable power stations and SolarSaga charging gear.
Oukitel Power
Oukitel ABR and P5000 series heavy-duty LiFePO4 generators, bidirectional 4000W AC inverters, and UPS zero-switching relays.
Ugreen PowerRoam
Ugreen PowerRoam series with BYD EV-grade LiFePO4 batteries, PowerZip AC fast charging, and U-Turbo inverter over-wattage modes.
Zendure
Zendure SuperBase semi-solid state LiFePO4 power stations, satellite battery balancing, and Balcony SolarFlow smart inverters.
Indexed Fault Guides in Power Stations
Machine-verified error code diagnostic walkthroughs
Inverter DC Bus Overvoltage
Error E03 triggers when the internal bidirectional inverter's high-voltage DC intermediate bus exceeds its safe operational voltage threshold (typically over 420V-450V DC). The Power Management System (PMS) locks out AC output and charging circuitry to prevent catastrophic failure of the primary IGBTs and bus capacitors.
Inverter DC Bus Overvoltage Trip
Error E04 triggers when the bi-directional inverter internal DC bus voltage exceeds safe hardware thresholds (typically >420V-450V DC). This occurs primarily during aggressive regenerative backfeed from inductive loads, solar PV open-circuit spikes, or rapid grid voltage fluctuations during AC pass-through.
High Solar Input Voltage Overload
Error E06 triggers when the DC input voltage to the MPPT charge controller exceeds the maximum absolute rating (60V DC on the low-voltage XT60 port or 140V DC on the high-voltage XT-60 port), causing the internal hardware over-voltage protection (OVP) circuit to trip and isolate solar charging to prevent MOSFET breakdown.
High PV Input Voltage Lockout
Error code E088 triggers when the open-circuit voltage (Voc) applied to the DC/PV input exceeds the hardware protection threshold of the internal MPPT controller (rated maximum 145V DC). The firmware initiates an immediate charge lockout to prevent catastrophic MOSFET breakdown.
PV Input Overvoltage Shutdown
The Bluetti AC240 hardware protection triggered Error E011 due to open-circuit voltage (Voc) at the DC/PV input exceeding the maximum rated threshold of 60V DC. The internal MPPT step-down controller has isolated the PV input bus via protective MOSFET switching to prevent gate breakdown and capacitor failure.
MPPT Over-Voltage Lockout Fix
Error code E088 indicates that the DC input voltage to the internal MPPT controller has exceeded the maximum rated safe threshold (145VDC), triggering a hardware-level safety shutdown to prevent buck converter MOSFET breakdown.
Inverter AC Short Circuit Protection
Error E034 triggers when the DSP controller detects an overcurrent spike or dead short across the pure sine wave inverter H-bridge output terminals, locking out the AC bus to protect the MOSFETs.
AC Inverter Overload Short Circuit
Error E06 indicates that the high-voltage AC pure sine wave inverter hardware protection circuit detected an instantaneous overcurrent, short circuit, or continuous load exceeding the 6,000W split-phase threshold, prompting a safety gate shutdown.
MPPT Solar Over-Voltage Protection Trip
The internal MPPT charge controller detected open-circuit voltage (Voc) exceeding the maximum hardware safety threshold of 145V DC on the DC/PV input port, triggering hardware protection to prevent catastrophic damage to the buck-boost conversion circuitry.
AC Inverter Overload Cutoff
Error code E32 indicates the bidirectional AC inverter sustained an instantaneous current or sustained wattage draw exceeding safety thresholds (typically >6000W surge or sustained >3840W continuous output), triggering software hardware protection to isolate the H-bridge MOSFETs.
Solar MPPT Input Overvoltage
Error E034 indicates the internal MPPT charge controller detected incoming DC voltage from the solar/PV array exceeding the maximum hardware safety threshold of 145V DC, triggering automatic hardware shutdown to protect the front-end MOSFETs.
PV Input Overvoltage Trip
Error E041 indicates that the DC/PV input voltage exceeded the maximum open-circuit limit of 145VDC, triggering the internal MPPT hardware overvoltage protection and latching the input relay to protect the DC-DC buck stage.
MPPT Controller PV Input Lockout
The internal MPPT charge controller has engaged a hardware lock state (F08) due to over-voltage, reverse polarity, excessive inrush current, or a short circuit detected at the XT90/Anderson solar input ports.
AC Output Short Circuit Overload
Error E041 indicates that the inverter microprocessor detected an immediate AC output short-circuit condition, an instantaneous peak current overload exceeding hardware thresholds (such as 6000W surge limit), or backfed AC voltage on the NEMA 14-50 or L14-30 output ports.
High Voltage MPPT Overvoltage Trip
Error 086 triggers when the high-voltage solar MPPT input port registers an open-circuit voltage (Voc) or transient surge exceeding the maximum rating (typically 150V DC or 600V DC depending on high-voltage port architecture), prompting the BMS and charge controller to trip overvoltage protection to prevent semiconductor destruction.
AC Pass-Through Overload Protection
Error 301 triggers when the bidirectional inverter detects an aggregate load on the AC output ports exceeding the safe pass-through rating (typically >3600W/30A at 120V or thermal limit under continuous bypass), forcing the AC transfer relay to trip to protect the internal bus and switching MOSFETs.
Split-Phase Inverter Phase Lock Fault
The internal bi-directional dual-inverter failed to synchronize the phase angle between L1 and L2 to exactly 180 degrees, or failed phase-locking loop (PLL) synchronization with an incoming AC grid/generator reference in split-phase mode. Hardware protection trips the AC output relays to prevent destructive shoot-through and circulating current.
High-Voltage Solar BMS Communication Fault
Error code ERR 115 signifies a communication timeout or data packet corruption between the internal High-Voltage Solar Input Controller (MPPT DC-DC subsystem) and the master Battery Management System (BMS). When the high-voltage bus (up to 150V DC / 15A) engages, the system isolates the charging circuitry via internal relay disengagement to protect the LiFePO4 battery pack from unregulated power flow.
Dual Inverter Sync Bypass Trip
Error 112 indicates that the internal dual-inverter synchronization circuit detected a phase discrepancy or high-voltage transient on the AC bypass bus, triggering hardware crowbar protection and locking out output relays to protect the split-phase power stage.
HV Solar MPPT Overcurrent Protection
Error E021 triggers when the high-voltage (HV) MPPT charge controller detects an input current exceeding its hardware rating (15A continuous, with transient limits). The internal DC-DC converter latches into hardware protection to safeguard the inverter's input bridge and switching MOSFETs.
Solar PV High Voltage Overload
Error code ERR 301 trips when the open-circuit voltage (Voc) applied to the High-Voltage Solar Input port exceeds the hardware threshold (typically 150V DC on the HV port or 60V DC on LV inputs), triggering an emergency BMS lock and disabling the MPPT controller to prevent MOSFET dielectric breakdown.
Bi-Directional Inverter Overload DC Bus
The ERR302 code indicates that the internal power management unit detected an overcurrent or overvoltage condition on the high-voltage DC bus linking the battery management system (BMS) and the bi-directional inverter bridge, triggering immediate hardware protection shutdown.
High-Voltage MPPT Overcurrent
Error 101 indicates the DELTA Pro 3's high-voltage solar MPPT tracker detected DC input current exceeding the maximum safe threshold (rated limit typically 15A), tripping the hardware or software overcurrent protection (OCP) circuit to prevent MPPT buck-boost MOSFET thermal breakdown.
Split Phase Inverter Overload Fault
Error 102 indicates an active split-phase bi-directional inverter overload or phase-balance fault. The internal DSP detected that current on either L1 (120V) or L2 (120V) exceeded rated limits, or an excessive phase-to-phase current imbalance occurred while operating in 120V/240V split-phase dual-voltage mode.
Bidirectional Inverter Split-Phase Overload
Error 302 indicates an instantaneous hardware overcurrent or sustained thermal overload on the bidirectional inverter stage during 120V/240V split-phase operation, tripping software-level protection or hardware fast-acting current sensors.
High Voltage Solar BMS Comm Error
Error 303 indicates an internal CAN/UART communication timeout or protocol mismatch between the high-voltage solar MPPT charge controller subsystem (30-150V port) and the main Battery Management System (BMS). This failsafe disengages the DC input relays to protect internal cell blocks.
Bi-Directional Inverter Pure Sine Wave Lockup
Error Code 302 designates a hardware-level overcurrent or short-circuit protection trip in the bi-directional inverter module. The system has latched the AC full-bridge H-bridge MOSFETs into high-impedance mode to prevent thermal runaway or DC-bus collapse caused by extreme inrush current, back-fed AC phase mismatch, or bridge driver latch-up.
High Voltage PV Overvoltage Fault
Error code ERR_066 is triggered when the DELTA Pro 3's high-voltage PV port detects an input open-circuit voltage (Voc) exceeding the 150V DC threshold, or when internal serial communication between the dedicated high-voltage MPPT sub-controller and the main BMS/logic board fails under high electrical stress.
PV Overvoltage Protection Tripped
Error ERR036 triggers when the open-circuit voltage (Voc) applied to the High Voltage Solar Input port exceeds the internal MPPT controller's absolute maximum rating of 150V DC. The safety hardware disconnects the solar charging bus to protect internal MOSFETs and DC-link capacitors from dielectric breakdown.
Solar Charging Overvoltage Cut-Off
Error 304 triggers when the PV input exceeds the maximum open-circuit voltage (Voc) threshold (typically 150V DC on the high-voltage port or 60V DC on the low-voltage port), forcing the MPPT controller into protection shutdown to prevent MOSFET dielectric breakdown.
High Voltage Battery Communication Fault
Error code D025 indicates a breakdown in isolated CAN bus serial communication between the DELTA Pro Ultra Inverter Module and the High Voltage (HV) LFP Battery Pack BMS. The inverter master controller triggers a fail-safe shutdown to prevent unmonitored charging or discharging across the high-voltage DC bus.
HV Battery Communication Timeout
Error 088 trips when the inverter head unit fails to establish or maintain bidirectional CAN/RS-485 communication with the internal BMS of one or more connected high-voltage (102.4V nominal) LFP battery packs within a 3000ms heartbeat window.
High-Voltage PV Inverter Overload
Error 303 indicates that the DELTA Pro Ultra's High-Voltage (HV) Solar/PV MPPT inverter stage has exceeded its maximum rated power (5600W), voltage (450V DC), or peak current input. The protection circuitry disengages solar charging to protect the internal DC-DC converter and switching FETs.
High Voltage MPPT Bus Overvoltage
Error code F007 indicates a hardware-level safety lockout on the high-voltage solar MPPT input. The internal DC bus detected open-circuit or operational voltage exceeding the rated 450VDC threshold, triggering gate drive shutdown to prevent catastrophic MOSFET/IGBT breakdown.
Dual Solar MPPT Overcurrent Trip
Error E041 indicates a dual solar MPPT hardware overcurrent protection trip. The internal DC-DC charge controller detected input current exceeding absolute hardware limits (High-PV port >30A peak or Low-PV port >15A peak), triggering an immediate solid-state disconnect to protect the buck-boost MOSFETs.
High Voltage Solar Overload
Error E15 triggers when the high-voltage photovoltaic (PV) input port detects open-circuit voltage (Voc) or sustained operating voltage exceeding the maximum threshold of 150V DC (or maximum wattage limits), initiating hardware protection to prevent MPPT charge controller damage.
Solar Input Overvoltage Protection Trip
Error ERR303 indicates that the MPPT solar charge controller has triggered hardware overvoltage protection (OVP). Open-circuit voltage (Voc) exceeding the maximum rating (e.g., 60V on the low-voltage PV port or 150V on the high-voltage PV port) was detected at the input terminals, shutting down charging to prevent MOSFET breakdown.
BMS Overload Relay Lockout
Error 062 indicates a safety lockout triggered by the Battery Management System (BMS) due to sustained AC/DC inverter overload or inrush current, causing the main DC contactor/relay to latch open or weld shut to prevent thermal runaway.
DC Bus Pre-Charge Failure
During power-on initialization, the bi-directional inverter's pre-charge circuit failed to bring the high-voltage DC link capacitor bank to the target threshold (approx. >380V DC) within the mandated pre-charge window (typically <500ms), triggering protective lockout ERR-303 to prevent destructive inrush current on the primary bypass contactor/FETs.
Cell Overvoltage Imbalance Error
Error ERR-BMS-302 trips when the internal Battery Management System detects an individual LiFePO4 cell exceeding the maximum safe threshold (typically >= 3.65V) or an inter-cell delta exceeding 150mV during high-voltage/high-current PV charging, triggering a charge cutoff latch to prevent thermal runaway.
CAN Bus Battery Pack Drop
The inverter controller detected excessive packet frame drops or frame transmission timeouts across the high-speed differential CAN 2.0B bus linked to the master battery pack BMS. In response, safety relays open, disconnecting the battery bank to prevent uncontrolled charge/discharge states or thermal runaway.
HV Bus Precharge Failure
The Battery Management System (BMS) detected that the DC high-voltage bus failed to achieve the target threshold (>90% of nominal battery voltage, approx. 92V-102V DC) within the specified precharge window (typically <500ms) prior to main contactor closure, preventing catastrophic inrush current.
HV Battery Comms Failure
Err106 designates a communication loss or packet timeout across the internal high-voltage CAN bus link between the DELTA Pro Ultra Inverter Module and the connected LFP Battery Pack(s). When BMS heartbeat telemetry drops below threshold, the inverter trips isolation relays to mitigate thermal and electrical hazards.
HV DC Bus Comm Fault
Error ERR301 indicates a critical communication timeout or packet corruption over the internal CAN/UART link between the High-Voltage (HV) DC-to-DC boost controller and the primary inverter DSP board, causing the system to isolate the 300V-450V DC bus for safety.
HV Inverter Short Circuit Trip
Error Code 043 indicates that the DELTA Pro Ultra's High Voltage (HV) split-phase inverter output stage detected an overcurrent/short circuit condition on the 120V/240V AC output rails. The digital signal processor (DSP) immediately shut down PWM gating to protect the power MOSFET/IGBT bridge from catastrophic thermal runaway.
BMS Inverter Communication Lost
Error 302 signifies a complete loss of CAN/RS485 data telemetry between the DELTA Pro Ultra inverter module and the stacked high-voltage LFP battery pack BMS. As a safety interlock, the inverter shuts down AC/DC outputs and halts HV DC bus charging to prevent over-voltage or thermal runaway.
High Voltage MPPT Overvoltage
Error ERR_114 indicates that the internal High-Voltage MPPT charge controller detected incoming DC solar input voltage exceeding the absolute maximum limit of 150V DC (rated 30-150V DC, 15A max). The firmware triggered emergency hardware isolation to prevent catastrophic destruction of the buck-boost MOSFETs and primary DC link capacitor bank.
BMS High Voltage Disconnect
Fault BMS-301 occurs when the DELTA Pro Ultra inverter loses high-voltage DC bus synchronization or differential CAN bus communication with an expansion battery pack, triggering safety isolation contactors to prevent HV arcing or thermal events.
HV Battery Interlock Communication Fault
ERR_BMS_028 indicates an open or unstable High-Voltage Interlock Loop (HVIL) or broken CAN bus communication circuit between the DELTA Pro Ultra inverter head and the external high-voltage LFP battery pack. The system has automatically isolated the DC bus contactors to prevent arcing and thermal events.
Inverter Output MOSFET Thermal Trip
Error Code 089 indicates an over-temperature protection trip on the high-voltage split-phase inverter stage. The primary power MOSFET/IGBT heatsink thermistor detected temperatures exceeding safety thresholds (>105°C), forcing an immediate inverter shutdown to prevent silicon junction breakdown.
BMS Communication Timeout Fault
Error 138 indicates a high-priority CAN/RS-485 serial communication handshake failure between the central inverter control board and the internal battery management system (BMS) pack or downstream modular battery units, triggering immediate AC/DC shutdown.
High Voltage Battery Communication Cutoff
The DELTA Pro Ultra Inverter detected an interruption or packet degradation on the proprietary CAN bus linking to the high-voltage LFP battery module. To prevent uncontrolled high-voltage DC transfer, the main contactors opened, triggering an emergency high-voltage isolation fault.
Dual Voltage AC Overload Trip
The bi-directional inverter's protection circuit triggered continuous tripping due to an excessive load surge, neutral-ground bonding loop, or split-phase imbalance exceeding the 4000W continuous / 8000W surge threshold across the 120V/240V split-phase bus.
HV PV Relay Latch Failure
Error 028 indicates a relay latch or pre-charge circuit failure on the High Voltage Photovoltaic (HV PV) MPPT boost stage. The main controller detected that the input isolation relay failed to cycle, welded shut, or could not overcome pre-charge bus differential voltage.
BMS Communication Link Failure
Error 095 indicates a loss of CAN bus/RS485 data telemetry between the internal/external Battery Management System (BMS) and the Master Control Board (MCB). When communication packets drop or timeout exceeding preset thresholds, the MCB trips protection interlocks, disabling AC/DC charge and discharge to prevent cell imbalance or thermal runaway.
Inverter High Ambient Overload
Error 043 triggers when the primary or secondary high-voltage inverter stage exceeds safe junction thermal limits under load due to excessive ambient operating temperatures (>45°C) or restricted forced-air cooling paths. The internal power management system locks out AC output to protect IGBT/MOSFET switches and DC-link bus capacitors from catastrophic thermal runaway.
Bi-Directional Inverter Surge Overload Trip
Error Code 403 indicates an AC bi-directional inverter overload trip triggered by a peak surge demand exceeding the hardware's 8000W surge threshold or a sustained inductive load exceeding 4000W continuous output. The integrated hardware protection circuit shuts down the H-bridge MOSFETs to prevent thermal avalanche.
High Voltage Inverter Cut Out
Error 033 triggers when the high-voltage DC bus or solar MPPT inverter stage exceeds safe operating thresholds (>450V DC), or detects an open/shorted IGBT bridge. The unit's firmware cuts output to protect the power electronics and battery bank.
HV MPPT High Temp Derating
Error 102 triggers when the high-voltage MPPT (Solar Port 2, 80-450V DC) heatsink or booster MOSFET temperature exceeds safe operating thresholds (>85°C). The BMS and inverter controller enforce thermal derating or charge cutoff to protect internal power electronics.
Inverter DC HV Bus Comm Failure
Error 304 triggers when the main system controller loses UART/CAN telemetry from the bidirectional inverter's high-voltage DC bus monitoring circuit. The BMS immediately disables AC/DC output paths to prevent uncontrolled DC link voltage runaway or IGBT shoot-through.
High-Voltage PV Isolation Fault
Fault 301 indicates that the High-Voltage (HV) Solar/PV input has detected either open-circuit voltage exceeding the 450V DC hardware ceiling or an active insulation resistance breakdown (isolation fault) to chassis ground while under high potential.
Inverter Inductive Surge Overload
Error 003 indicates that the bidirectional inverter H-bridge detected an instantaneous current spike exceeding the hardware peak current threshold (overcurrent/desaturation protection). This typically occurs when starting high inrush inductive loads (e.g., heavy compressors, AC units, well pumps) or from transient back-EMF feedback.
AC Output Overload Error 106
Error 106 indicates an AC inverter hardware overcurrent protection event caused by severe inrush current exceeding surge limits (typically >8000W transient or prolonged >4000W continuous) from highly inductive loads like compressors, pumps, or large power tools.
MPPT High Voltage PV Overcurrent
Error code 087 indicates that the high-voltage MPPT solar charge controller has detected an incoming direct current (DC) amperage exceeding its maximum rated hardware threshold (nominal continuous limit is 15A; peak trip threshold at approximately 16.5A-17A). The charge controller automatically isolates the PV input to protect the internal buck-boost circuitry and power MOSFETs.
High Voltage Solar Overload Trip
The EcoFlow DELTA Pro 3 high-voltage PV charging port exceeded its operational limit (max 150V DC / 15A), causing the Battery Management System (BMS) and internal MPPT controller to latch into hardware overvoltage and overcurrent protection to prevent busbar damage and battery cell degradation.
High-Voltage PV Input Overvoltage
Error ERR305 triggers when the open-circuit voltage (Voc) applied to the Delta Pro 3 high-voltage PV port exceeds the maximum allowable hardware threshold of 150V DC. The internal MPPT controller opens protection MOSFETs to prevent overvoltage breakdown of input filter capacitors and switching semiconductors.
AC Inverter Inductive Overload 104
Error 104 triggers when the AC inverter's hardware current-sensing circuitry (shunt/hall sensor) detects an inrush current exceeding the unit's peak surge threshold (typically >8000W peak or >70A momentary spike), caused by high inductive loads such as heavy compressors, pumps, or large electric motors tripping the fast overcurrent protection (OCP).
High Voltage PV Overvoltage Fault
The internal High-Voltage MPPT controller detected an open-circuit voltage (Voc) exceeding the absolute maximum threshold of 450V DC on the High-PV port, triggering safety isolation relays to prevent inverter MOSFET breakdown.
Inverter HV Bus Overvoltage
Error 049 is triggered when the internal DC high-voltage bus linking the DC-DC boost stage and the DC-AC full-bridge inverter exceeds safety thresholds (>450V DC). The firmware latches the gate drivers into a shutdown state to prevent catastrophic IGBT/MOSFET rupture.
Battery Communication Link Lost
Error 062 indicates a CAN bus/RS485 serial communication failure between the DELTA Pro Ultra inverter module and the expansion LFP battery pack. The inverter safety supervisor tripped due to missing heartbeat telemetry packets.
Solar Input BMS Communication Failure
Error 045 indicates an internal communication timeout or packet corruption between the High-Voltage Solar Input Controller/MPPT subsystem and the primary Battery Management System (BMS). The system trips input protection relays to prevent over-voltage battery charging.
Battery Discharge Overcurrent Trip
Error 059 triggers when the internal Battery Management System (BMS) detects DC discharge current exceeding safe hardware thresholds (typically >105A peak surge or continuous rated limit), immediately shutting down inverter and DC output rails to protect the LiFePO4 cells and low-side MOSFET bank.
AC Inverter High Voltage Cutoff
Error 101 triggers when the bidirectional inverter's internal DSP detects an incoming AC grid or generator voltage surge exceeding the safety threshold (typically >140VAC on 120V nominal lines or >265VAC on 230V nominal systems), causing the pass-through relay and inverter circuit to immediately latch off to prevent downstream board and connected appliance damage.
Inverter Overload Low Load Trip
Error 303 signals that the inverter protection circuit tripped due to an anomalous current surge or DC bus imbalance detected during low-load or no-load conditions. The primary AC output safety relay disengages to prevent shoot-through failure in the GaN/MOSFET H-bridge stage.
240V Split-Phase Sync Failure
The bidirectional high-frequency inverter's Phase-Locked Loop (PLL) failed to synchronize L1 and L2 legs within the required 180-degree (+/- 5 degrees) phase offset, causing the master DSP to trip protection relays to prevent cross-phase short circuits or reverse backfeed.
Dual Inverter Phase Sync Overload
Dual-inverter phase synchronization and overcurrent protection tripped on the L1/L2 split-phase topology. The internal digital signal processors (DSPs) detected an excessive phase-angle deviation from 180 degrees, circulating neutral currents, or severe dynamic cross-conduction between the two 120V inverter bridges under load.
Battery Discharge Overcurrent Trip
The inverter controller detected an instantaneous or sustained discharge current exceeding safe hardware limits across the high-voltage DC bus (102.4V nominal LiFePO4 stack), prompting a hardware-level safety shutdown to prevent cell degradation, FET thermal runaway, or inverter bridge failure.
Inverter Communication Bus Failure
Error ERR 120 denotes a CAN/RS-485 bus communication timeout or data packet corruption between the main battery management system (BMS)/system controller and the internal bidirectional high-voltage AC inverter module. The system has entered a hardware failsafe state to prevent out-of-sync switching and DC bus runaway.
HV Battery Communication Loss
Error 094 indicates a fatal CAN bus/RS485 communication timeout between the DELTA Pro Ultra Inverter Module and the external High Voltage LFP Battery Pack (nominal 102.4V). The master BMS safety interlock trips, preventing inverter engagement and battery discharge to prevent unmonitored cell imbalance or thermal events.
Inverter HV DC Bus Overcurrent
Error 301 triggers when the high-voltage DC bus (nominally 380V-420V DC) linking the battery boost stage and the bidirectional inverter detects an instantaneous current spike exceeding safe operational thresholds (typically >35A peak). The DSP controller trips hardware shutdown to protect the primary power MOSFETs/IGBTs from punch-through failure.
INV 301 HV Bus Overvoltage
Error code INV 301 indicates that the internal DC High-Voltage (HV) bus has exceeded the safety overvoltage threshold (typically nominal 380V-420V DC spiking past 450V DC). The inverter protection circuit triggers an immediate hardware latch-off to protect power MOSFETs/IGBTs from breakdown caused by PV overvoltage spikes, regenerative back-EMF, or AC input surges.
High-Voltage Solar Overvoltage Lockout
Error ERR-304 triggers when open-circuit voltage (Voc) on the high-voltage PV port exceeds the hardware threshold of 150V DC (often exacerbated by low temperature coefficients), causing the MPPT controller to latch shut to protect internal DC bus capacitors and buck-boost MOSFETs.
Cell Overvoltage Imbalance Fault
Error ERR_BMS_301 triggers when the Battery Management System detects an individual LiFePO4 cell voltage exceeding the upper safety threshold (>= 3.65V to 3.75V) or an excessive inter-cell delta (> 100mV-150mV) during charging, disabling input charge FETs to prevent thermal runaway.
High Voltage Solar Overcurrent Fault
Error 306 indicates that the high-voltage MPPT solar charge controller or Battery Management System (BMS) detected DC input current exceeding the design limit (15A continuous, with hardware trip typically occurring near 16A-17A). The charge controller has entered hardware protection mode to protect internal MOSFETs and the main LiFePO4 battery bus.
Bidirectional Inverter Bypass Tripping
The EcoFlow DELTA Pro 3's high-voltage bidirectional inverter bypass mechanism trips when the transfer relay encounters excessive inrush current, grid phase-angle mismatch, or internal DC-link overvoltage during AC grid-to-battery passthrough transition.
DC-DC Inverter Overcurrent Fault
The main bidirectional inverter controller tripped hardware overcurrent protection on the primary DC-DC intermediate stage. This occurs when instantaneous current through the primary H-bridge or synchronous rectifiers exceeds factory safety thresholds during high-power charging or discharge transitions.
High Voltage Solar MPPT Overvoltage
Fault code BMS-014 indicates the internal High-Voltage (HV) MPPT charge controller detected open-circuit string voltage (Voc) exceeding the safety ceiling of 450V DC (hardware absolute max 500V DC). The solid-state protection switches tripped to prevent catastrophic destruction of the internal buck-boost stage and battery bus.
BMS High Voltage Communication Loss
Error code BMS 302 on the EcoFlow DELTA Pro Ultra indicates an internal or inter-stack CAN/RS485 communication timeout between the high-voltage battery management system (BMS) and the inverter unit, triggering a protective relay disconnect to prevent unbalanced HV DC bus operation.
BMS Cell Overvoltage Lock
The Battery Management System (BMS) detected a single or multi-cell LFP voltage spike exceeding the hard ceiling threshold (typically >=3.75V per cell or total pack safety ceiling), triggering a latching protection lock to isolate the DC high-voltage bus and halt charge/discharge operations.
HV Discharge Communication Timeout
Error BMS_ERR_017 indicates a loss of CAN bus or serial heartbeat telemetry between the Delta Pro Ultra battery pack BMS and the inverter module during high-voltage (>100V DC) discharge operation, triggering automated protective contactor isolation.
High Voltage PV Overload Cutoff
Err024 triggers when the High-Voltage (HV) Solar Input port exceeds maximum allowable DC input limits (rated 450V DC Max, 15A Max). The internal MPPT controller opens input protection FETs to prevent bus overvoltage and inverter damage.
BMS Communication Link Failure
Error 102 indicates an interruption or packet loss in the high-voltage serial/CAN bus communication between the inverter unit and the external LFP battery module. The main controller initiates safe shutdown of high-voltage DC contactors to prevent thermal runaway or unbalanced pack discharge.
HV Solar BMS Communication Timeout
The inverter unit has lost real-time CAN bus telemetry from the internal charge controller or stack battery BMS during high-voltage solar harvesting (80-450V DC). The central supervisory controller trips solar charging protection to prevent thermal runaway and overvoltage.
High-Voltage MPPT Overcurrent Lock
Error E031 triggers when the high-voltage solar MPPT input controller detects an incoming current exceeding the maximum design limit (typically >15A continuous or a transient inrush spike over threshold), causing the firmware to latch an overcurrent protection lock on the photovoltaic subsystem.
Bidirectional Inverter Overcurrent Fault
Hardware protection triggered by the bidirectional inverter stage detecting instantaneous current exceeding safe operational limits (>40A peak AC bus or rapid DC link surge) during high-load charging or sudden AC surge discharge.
Inverter Overload Inrush Shutoff
Error 103 trips when the bidirectional inverter detects an instantaneous peak current draw exceeding the surge capacity rating (typically >8000W peak or sustained >4000W at 120V/240V), initiating immediate solid-state protection to prevent MOSFET and H-bridge destruction.
AC Inverter Overload Protection Lock
Error 305 indicates that the internal bidirectional AC inverter has engaged a hard software lock due to continuous sustained over-current, an extreme surge demand exceeding peak limits (over 8000W surge or 4000W continuous), or a dead short circuit detected on the AC output bus.
Inverter Overload High Voltage Cutoff
The bi-directional inverter detected an AC over-voltage condition or regenerative inductive back-EMF spike that exceeded the DC bus operating ceiling (>450V DC), triggering the hardware Over-Voltage Protection (OVP) cut-off to protect the GaN/MOSFET H-bridge.
Inverter Overload PV Fault
The bi-directional inverter control MCU tripped protection due to simultaneous AC inverter load saturation and an over-voltage condition on the high-voltage solar (PV) input port exceeding the 150V DC threshold.
DELTA Pro 3 False Overload Trip
The unit triggers a false continuous AC overload protection trip at or below its rated 4000W threshold. This fault typically originates from uncalibrated current shunt sensors, high inrush current triggers on purely resistive or reactive loads, out-of-spec power factor tolerance, or outdated inverter DSP firmware thresholds.
BMS Cell Imbalance Cut-Off
The internal Battery Management System (BMS) tripped an over-voltage or differential cutoff due to an excessive voltage spread (>100mV–300mV) between series-connected LiFePO4 cells during high-state-of-charge operation, locking charge acceptance to prevent thermal runaway.
High Voltage PV Overvoltage Trip
Error 038 indicates that the open-circuit voltage (Voc) applied to the High-Voltage (HV) PV input port exceeded the internal hardware limit of 450V DC. The internal MPPT charge controller initiated an emergency hardware overvoltage trip to protect the DC-DC boost stage and inverter circuitry.
BMS Battery Cell Imbalance
Error 059 triggers when the Battery Management System (BMS) detects a cell voltage delta exceeding factory threshold limits (typically >150mV–300mV variance between series LFP cells) in the high-voltage battery stack, disabling charging or discharge to prevent thermal runaway and cell degradation.
High-Voltage MPPT Overvoltage Trip
The High-Voltage (HV) MPPT input has tripped protection code ERR03 due to DC bus overvoltage exceeding the inverter's absolute maximum rating of 450V DC. In sub-freezing ambient temperatures, solar photovoltaic (PV) open-circuit voltage (Voc) increases significantly due to negative temperature coefficients, pushing series string voltage past safe operating limits.
HV Stack Communication Fault
The inverter central supervisor lost CAN bus packet telemetry from one or more stacked high-voltage battery modules (nominally ~102.4V per pack, up to 300V+ stacked). Safety interlocking opened internal solid-state and DC contactors to prevent DC bus desynchronization.
Inverter DC Bus Overvoltage
Error ERR_032 indicates that the internal DC-DC booster has exceeded the safe maximum DC high-voltage bus threshold (nominally >450VDC) feeding the primary full-bridge inverter stage. The system initiates an emergency hardware interrupt to protect the power MOSFETs/IGBTs and filter capacitors from catastrophic dielectric breakdown.
HV PV Soft Start Failure
Error 030 triggers when the high-voltage (HV) PV input stage fails to complete its precharge sequence. The DELTA Pro Ultra utilizes an active inrush current limiting circuit (resistors/NTCs and bypass relays) to charge internal DC-link intermediate capacitors before engaging the full MPPT boost stage. If intermediate bus voltage fails to reach the design threshold within the precharge timeout window, or an overcurrent/short circuit is sensed, the firmware trips error 030 to protect the HV inverter semiconductors.
Inverter High-Voltage MPPT Comms Failure
Error 086 indicates an internal CAN/UART communication loss between the main inverter control board and the integrated High-Voltage (HV) MPPT charge controller sub-assembly. This trips hardware protection and halts high-voltage solar harvesting.
High Voltage MPPT Bus Communication Failure
Error 114 indicates an internal communication timeout or signal integrity loss over the internal CAN/UART data bus between the High-Voltage (HV) Solar MPPT charge controller sub-assembly and the main inverter control DSP. The system locks out HV solar charging (80-450V input) to prevent uncontrolled DC bus overvoltage or catastrophic thermal runaway.
Inverter Soft Start Precharge Failure
Error ERR 022 triggers when the high-voltage DC bus precharge circuit fails to elevate the DC-link capacitor voltage to the target threshold (typically >90% of nominal ~102V battery pack voltage) within the designated soft-start timeout window, aborting full inverter contactor engagement to prevent inrush current damage.
Stack Communication Bus Timeout
The main inverter management unit failed to establish or maintain bidirectional CAN/RS-485 serial communication with the high-voltage LFP battery stack BMS over the proprietary inter-stack connection bus. This trips system-wide safety cutoffs and halts power conversion.
Battery Inverter CAN Bus Fault
Error ERR_084 indicates a loss of internal CAN/RS485 data telemetry between the DELTA Pro Ultra Inverter Module and the stackable LFP Battery Pack. The system BMS isolates DC contactors to prevent unmonitored thermal or overcurrent states.
Split Phase Inverter Overcurrent
Error ERR_INV_301 indicates hardware protection trip caused by an instantaneous or sustained overcurrent condition across the 120V/240V split-phase inverter bridge. The inverter's primary current shunt or Hall sensor detected current exceeding peak threshold (typically >30A continuous or >60A surge per leg), tripping gate drivers to protect the silicon carbide (SiC) MOSFET array.
AC Inverter Overload Lockout
Error E01 triggers when the bidirectional inverter detects an AC output current or wattage spike exceeding continuous (6,000W) or peak surge (9,000W) thresholds, an active downstream dead short, or a neutral-ground bonding phase conflict via an external transfer switch.
AC Output Overload Trip
Error Code E04 indicates that the internal digital signal processor (DSP) detected an AC output overcurrent or excessive surge demand exceeding continuous (6,000W) or peak (9,000W for >200ms) inverter thresholds, or encountered a severe phase imbalance across the split-phase L1/L2 120V/240V legs.
AC Output Overload Trip / Inverter Protection Locked
The Delta Pro 3 4000W high-frequency pure sine wave inverter shuts down all 120V and 240V AC output sockets with an audible alarm and pulsing OVERLOAD indicator when an inductive appliance inrush current exceeds the 8000W X-Boost surge threshold.
Inverter Bus Overvoltage Surge
Error ERR 032 triggers when the internal high-voltage DC bus exceeds safe operating thresholds (typically >450V DC) during dynamic or reactive load switching. Inductive loads like well pumps, air compressors, or heavy motor drivers produce back-EMF and transient voltage spikes that feed back into the DC intermediate circuit, causing the DSP supervisory controller to trip protective latching isolation to prevent bridge MOSFET/IGBT breakdown.
Inverter BMS Communication Loss
Error 048 indicates a serial data bus failure between the DELTA Pro Ultra inverter module and the Battery Management System (BMS) over the internal RS-485 interface. The inverter controller trips into fail-safe mode and cuts off AC/DC output when telemetry heartbeat frames are interrupted.
BMS Cell Imbalance Cutoff
BMS Error 103 triggers when the internal battery management system detects an excessive cell voltage variance (Delta V typically exceeding 150mV to 250mV) across the 16S LiFePO4 series pack during active charging or heavy discharge. The BMS executes a balance cutoff to prevent individual cell overvoltage (>3.65V) or deep discharge collapse (<2.50V).