Sol-Ark Inverter Settings Guide

We put together this handy guide for Sol-Ark inverter users to document and elaborate on what each setting means. Sometimes inverter manuals are vague on the meaning of certain settings, and sometimes the manufacturer’s tech support doesn’t even get it right. Our goal is to provide a comprehensive guide with additional commentary.

If you have any feedback on this guide, please put it in the comments below so we can continue to improve upon it.

 

Click any setting name to expand a detailed explanation of what it does and how to configure it. Example values shown are typical for a residential 48V LFP battery system. Descriptions are based on the Sol-Ark Programming Guide V2.0 and the Sol-Ark 15K Installation Manual. Always verify settings against your specific battery manufacturer specifications and utility interconnection requirements.



1. Basic Setup

Display preferences, clock, advanced hardware options, security locks, and parallel configuration. Access via System Setup → Basic Setup.

Display

Setting Value
Brightness
Controls the brightness of the LCD touchscreen. Adjusted via slider. Dimming the display reduces parasitic draw and extends backlight life. On outdoor installs in direct sun, maximum brightness is recommended for readability.
Slider
Beep
Enables or disables audible beeps when buttons are pressed on the touchscreen. Useful for confirming input in bright environments where the screen is hard to read. Disable if the inverter is in a living space where noise is disruptive.
Enabled
Auto Dim
When enabled, the screen automatically dims after the set timeout period to reduce power draw and extend backlight life. The checkbox enables the feature; the value sets how many seconds of inactivity before dimming. Default is 600 seconds (10 minutes). A second slider controls the dim brightness level.
ON — 600s

Time

Setting Value
AM/PM Format
Selects 12-hour (AM/PM) versus 24-hour clock display. Enabling the checkbox sets the clock to 12-hour format. Matters for reading TOU time slots correctly on the screen.
ON (12-hr)
Date / Time
Manual fields for setting the current year, month, day, hour, minute, and second. The internal clock drives TOU scheduling, the generator exercise cycle, and event timestamps in the alarm log. An incorrect clock will cause TOU time slots to fire at the wrong times.
2026-04-03 08:04
Time Sync
When checked, the inverter syncs its internal clock with an NTP (Network Time Protocol) server over the internet, provided the Wi-Fi dongle is connected and active. Keeps the clock accurate without manual adjustment. Highly recommended when the inverter has a reliable Wi-Fi connection to MySolArk.
ON
Seasons
Defines up to three seasonal date ranges (Season1, Season2, Season3) that can apply different TOU schedules depending on the time of year. Useful for customers with time-of-use utility rates that change by season. When unchecked (disabled), the same TOU schedule applies year-round. The start and end dates for each season are entered in month-day format (M-D). Default season ranges are pre-loaded; modify to match your utility’s seasonal rate schedule if applicable.
OFF

Advanced

Setting Value
Solar Arc Fault ON
Enables the inverter’s internal arc fault detection algorithm on the PV input terminals. When active, the inverter monitors the DC string inputs for arc fault signatures and will trigger fault code F63 if an arc is detected. This feature helps comply with NEC 690.11 AFCI requirements where required. When unchecked, arc fault detection on the MPT inputs is disabled.
OFF
Clear Arc Fault
Manual command button to clear an arc fault event (F63) from the inverter’s fault register. Must be executed manually each time an arc fault is detected before normal operation can resume. The underlying wiring issue causing the fault should always be identified and corrected before clearing. Do not clear repeatedly without investigating the root cause.
Button
ARC Parameters
A read-only column of seven calibration values used internally by the arc fault detection algorithm. These are factory-set parameters and should not be modified in the field. They define detection thresholds and timing windows for arc fault signal pattern recognition. Typical values: 030000, 045000, 000800, 000050, 000530, 000100, 238094.
Factory values
Gen Peak-Shaving
When enabled, the inverter uses battery power to limit the load placed on the generator to the programmed Gen Limit Power value. If loads exceed the limit, the battery discharges to make up the difference instead of overloading the generator. This protects small generators from overload. Disable when no generator is connected, or when generator peak-shaving is not needed.
OFF
Gen Limit Power
Sets the maximum continuous power (in watts) the inverter is allowed to draw from the generator. Only active when Gen Peak-Shaving is enabled. This value should be set below the generator’s rated continuous output to avoid overloading it. Default 8000W. Multiply the generator’s rated voltage by its rated amperage to determine a safe ceiling. For example, a 10kW generator running 120/240V should have this set no higher than 8,000–9,000W to maintain a safe operating margin.
8000W
Load Limit Power
Sets the maximum total AC load the inverter will supply to the LOAD terminals before relying on the grid to cover additional demand. If total load exceeds this value when in peak-shaving mode, the inverter caps its contribution and the grid covers the remainder. A value of 14000W matches the Sol-Ark 15K continuous output rating.
14000W
Grid Peak-Shaving
When enabled, the inverter uses battery power to limit the power drawn from the utility grid to the programmed Power value. When grid demand exceeds that threshold, the battery discharges to make up the difference, preventing demand charges from spiking. Requires CT sensors to be installed for accurate grid monitoring. Disable for standard solar-only configurations.
OFF
Grid Peak-Shaving Power
The maximum grid draw (watts) before battery kicks in during grid peak-shaving. Only active when Grid Peak-Shaving is enabled. Size this below the utility demand charge threshold you want to avoid.
8000W
Auto Detect Home Limit Sensors
When enabled, the inverter automatically detects and configures the type of current transformer (CT) sensors installed on the grid/service entrance lines. This simplifies setup; the inverter queries the CTs and sets the CT ratio automatically. If using non-standard CTs or CTs with a ratio other than the default 2000:1 (100A:50mA), disable this and set the CT ratio manually. When disabled, set the CT ratio manually in the CT Ratio field below.
OFF
CT Ratio
Specifies the transformation ratio of the external current transformer (CT) sensors. The Sol-Ark ships with 100A split-core CTs with a 50mA output, giving a native ratio of 2000:1 (2000 CT units). If third-party CTs are used, set this accordingly. An incorrect CT ratio causes inaccurate power readings, which directly affects Limited Power to Home behavior and grid sell accuracy. Default: 2000 (for the included 100A Sol-Ark CTs).
2000
UPS Time
Sets the transfer time (in milliseconds) from grid-tied operation to backup power mode after the grid disconnects. A value of 0ms represents the fastest possible transfer. The Sol-Ark 15K is capable of <10ms transfer times on newer firmware, which is fast enough for most electronics. The default in the manual is listed as 5ms. When set to 0ms, the inverter uses its minimum hardware transfer time without any programmed delay. Some loads (motors, certain UPS devices) benefit from slightly longer transfer times.
0ms

Factory Reset

Setting Value
Factory Reset
Resets all inverter settings to factory defaults. This is irreversible and will erase all custom programming including TOU schedules, battery settings, grid parameters, and communication addresses. Document all settings before using this. Typically only needed when reprogramming a previously commissioned unit or troubleshooting a setting conflict that cannot be isolated.
Button
System Selfcheck
Initiates an internal self-diagnostic test. The inverter checks key hardware subsystems including IGBT gate drivers, DC bus voltage, AC output relays, and communication buses. Useful during commissioning or when troubleshooting unexplained faults. The inverter may briefly interrupt output during the test.
Button
Lock Out All Changes
Enables a settings lock that prevents any programming changes from being made through the touchscreen. Useful after final commissioning to prevent accidental changes by homeowners or non-authorized personnel. A password or physical access may be required to unlock. Some installers enable this after system sign-off.
OFF
Test Mode
Puts the inverter into a diagnostic test mode. Used during commissioning and factory verification. Not intended for normal operation. Enabling this during live operation may disrupt system behavior. Only use when instructed by Sol-Ark technical support.
OFF
Lock Grid Charging & Limited
Locks the Grid Charging and Limited Power mode settings to prevent changes. This is commonly required by utilities or AHJs as a condition of interconnection. It prevents the homeowner from enabling grid sell or changing the export limit after utility approval. Some utilities require this to remain locked as a condition of the net metering agreement. May be required by the utility as a condition of the interconnection agreement.
ON

Parallel

The Sol-Ark 15K-P supports stacking multiple inverters for higher power output. This tab configures parallel operation roles, addressing, and meter assignments.

Setting Value
Parallel
Enables parallel mode. When checked, this inverter participates in a parallel group with other Sol-Ark units. The inverters communicate over a CANbus link to synchronize output voltage, frequency, and load sharing. Parallel mode must be enabled on all units in the group, with one designated Master and the rest as Slaves. When Parallel is enabled, this inverter participates in a group with other Sol-Ark units.
ON
Master / Slave
Designates the role of this inverter in the parallel group. The Master unit controls frequency and voltage reference; all Slave units follow the Master. In a 120/240V split-phase parallel system, two Sol-Ark units are typically stacked as two inverters on the same phase, or as Master (Phase A) and a second unit on Phase A for doubled output. In a 3-phase configuration, each unit is assigned to a different phase. Only one Master is allowed per parallel group. One unit per group must be designated Master.
Master
Modbus SN
The Modbus serial number (address) that uniquely identifies this inverter on the parallel CANbus network. Each unit in a parallel group must have a unique Modbus SN. Default is 01 for the first unit. Slave units are typically assigned 02, 03, etc. This value also appears in alarm logs and monitoring data to identify which unit generated a fault. Default is 01 for the first unit.
01
Phase Assignment
Assigns this inverter to Phase A, Phase B, or Phase C in multi-phase parallel configurations. For standard residential 120/240V split-phase systems, all units are assigned to Phase A. For commercial 120/208V 3-phase systems, three inverters are each assigned to one of the three phases. Incorrect phase assignment in a 3-phase system will result in a “Grid Phase Wrong” error. For standard residential split-phase, all units are typically assigned Phase A.
Phase A
Meter → Grid / Meter → Load
In parallel systems, external power meters can be assigned to monitor the grid connection point (Meter→Grid) or the load output (Meter→Load). This enables more accurate real-time monitoring of power flow at each point. Enable and assign a meter type only when external meters are physically installed.
OFF / OFF
MeterSelect (Grid / Load)
Selects the meter type for each monitored connection point when Meter→Grid or Meter→Load is enabled. Options include No Meter, and various supported third-party meter models. Set to “No Meter” when no external meters are installed.
No Meter / No Meter



2. Battery Setup

All battery-related programming: bank sizing, charge and discharge voltages, protection thresholds, smart load control, and wind turbine input. Access via System Setup → Battery Setup.

Batt (Battery Bank)

Setting Value
Batt Capacity
Total usable capacity of the battery bank in amp-hours (Ah). Used by the inverter to calculate the state of charge (SOC) percentage when operating in open-loop voltage mode. For closed-loop BMS systems, this value is still required for proper display and TOU threshold calculations. Set this to the sum of all batteries in the bank. Example: eight 300Ah batteries in parallel = 2400Ah. Set this to the total Ah capacity of your battery bank.
2400Ah
Max A Charge
Maximum DC charge current (amps) the inverter will send to the battery bank from all sources (solar MPPT + AC sources combined). The Sol-Ark 15K-P can deliver up to 275A when both battery terminal sets are used. Using only one set of terminals limits this to 160A maximum. Set this value at or below what the battery manufacturer specifies as the maximum charge rate. Up to 275A when both battery terminal sets are used; up to 160A with a single terminal set.
275A
Max A Discharge
Maximum DC discharge current (amps) the inverter will draw from the battery bank to supply AC loads. Same 275A / 160A dual-terminal limitation applies as with charge. Setting this too high relative to battery specs can damage the battery bank, particularly LFP cells at low SOC. The BMS will also enforce its own limit; the inverter respects whichever is lower. Up to 275A with both terminal sets; up to 160A with one set.
275A
TEMPCO
Temperature compensation coefficient for charging voltage, expressed in millivolts per degree Celsius per cell (mV/C/Cell). Used with lead-acid batteries to adjust charge voltage as temperature changes. For lithium batteries (LFP, NMC), this must be set to 0 mV/C/Cell since lithium chemistry does not require or benefit from temperature-compensated charging. Setting it to a non-zero value with lithium batteries can cause overcharging at low temperatures. Must be 0 mV/C/Cell for all lithium chemistries.
0 mV/C/Cell
Use Batt V Charged / Use Batt % Charged
Selects whether the inverter uses battery terminal voltage (V) or BMS-reported SOC percentage (%) as the primary reference for all battery threshold comparisons. When a BMS is connected and communicating, “Use Batt % Charged” should be selected because the BMS provides an accurate coulomb-counted SOC that is far more reliable than voltage estimates, especially under load. If no BMS is connected (open-loop), select “Use Batt V Charged” to use voltage as the SOC proxy. Use Batt % Charged when a BMS is connected; Use Batt V Charged for open-loop systems.
% (BMS SOC)
No Battery
Enables grid-tie-only mode with no battery bank. When checked, the inverter runs as a simple grid-tie inverter. Many advanced features (TOU, backup power, peak shaving) are unavailable without a battery. Uncheck when a battery bank is installed and active.
OFF
BMS Lithium Batt
Enables closed-loop BMS communication between the inverter and a compatible lithium battery via the CANBus or RS-485 port. When active, the BMS sends real-time SOC, cell voltage, temperature, and current limit data directly to the inverter, replacing inverter-estimated values. The numeric field (00) sets the BMS ID; 00 = auto-detect. If multiple BMS units are connected, set unique IDs for each. Enable when using a compatible lithium BMS. ID 00 = auto-detect. Verify BMS communication via the Li-Batt Info screen.
ON — ID: 00
Activate Battery
Activates the battery bank for use by the inverter. Must be checked for the battery to participate in charging, discharging, and backup power. Unchecking this while a battery is physically connected will cause the inverter to operate as if no battery is present. Should be ON whenever a battery bank is installed.
ON

Charge

Two-column values below are Gen (left) / Grid (right) where applicable.

Setting Value
StartV (Gen / Grid)
The battery voltage at which AC charging from the generator (left) or utility grid (right) is allowed to begin. Once the battery drops below this voltage, the inverter requests charging from the respective AC source. When TOU is active, AC charging only starts in time slots where the Charge checkbox is enabled. The Gen start voltage must be lower than the TOU “Batt” target for correct behavior. Set Gen StartV slightly lower than Grid StartV. Must be below the TOU Batt target when TOU is active.
49.0V / 49.8V
Start% (Gen / Grid)
SOC percentage threshold for initiating AC charging from the generator or grid. Same logic as StartV but expressed as a percentage. When “Use Batt % Charged” is active, this value governs (not StartV). The inverter starts Gen or Grid charging when SOC falls below the respective Start%. Must be set lower than the TOU Batt% target for correct operation with TOU enabled. Set Gen Start% below the TOU Batt% target. Grid Start% sets the floor for overnight grid charging if used.
50% / 22%
A (Gen / Grid Charge Rate)
Maximum DC charge current (amps) allowed when charging from the generator (left) or utility grid (right). Limits how hard the battery is charged from each AC source independently. Lower values reduce generator loading; higher values charge faster. This is separate from the overall Max A Charge limit. Size the Gen A value to stay well within the generator’s continuous output rating. Grid A can be set higher when charging from utility.
40A / 125A
Gen Charge
Master enable for generator-based battery charging. When unchecked, the inverter will never charge the battery from the generator regardless of SOC, StartV, or TOU settings. When checked, charging from the generator will occur when the battery drops below the StartV or Start% threshold (or during TOU Charge slots). Enable only if a generator is connected and generator-based battery charging is desired.
OFF
Grid Charge
Master enable for grid-based battery charging. When checked, the inverter can charge the battery from the utility grid. This is commonly enabled for systems that need overnight off-peak charging from the grid. When TOU is active, grid charging only occurs during time slots where the Charge checkbox is selected. When TOU is off and Grid Charge is on, charging happens anytime the battery falls below Start% or StartV. Enable if you want the grid to charge the battery, typically controlled by the TOU Charge column.
ON
Float V
The voltage the inverter holds the battery at after completing the absorption charge stage. For LFP (lithium iron phosphate) batteries, Float V is typically set equal to or slightly below Absorption V. Many LFP manufacturers actually recommend no float stage at all (or setting Float = Absorption) to prevent unnecessary top-balancing stress. For 48V LFP banks, typical Float V is 53.2V to 54.4V. Verify against your battery manufacturer’s spec sheet.
53.2V
Absorption V
The target charge voltage during the bulk and absorption phases. The inverter ramps up to this voltage and holds it until charge current tapers off, indicating a full charge. For a 48V LFP bank, the standard absorption voltage is 54.4V to 56.0V depending on the battery manufacturer. Verify against your battery manufacturer specifications. Lower values reduce cell stress but may result in the battery not reaching 100% SOC.
53.2V
Equalization V
The voltage applied during periodic equalization charging. For lead-acid batteries, equalization is a deliberate overcharge cycle to balance cells. For LFP lithium batteries, equalization in the traditional lead-acid sense is not required or recommended. When an LFP system is used, this value should typically be set equal to Absorption V to disable effective equalization. For LFP systems, set Equalization V equal to Absorption V. The interval (30 days) and duration (0.0 hours) fields control how often equalization runs; 0.0 hours effectively disables it.
53.2V
Equalization Interval / Duration
Controls how frequently the equalization cycle runs (every N days) and how long it lasts (hours). With LFP batteries, duration should be set to 0.0 hours to disable active equalization. For LFP batteries, set Duration to 0.0 hours to disable active equalization.
30 days / 0.0 hrs
Generator Exercise Cycle Day & Time
Programs an automatic weekly generator exercise start. The inverter will start the generator on the specified day at the specified time and run it for the specified number of minutes. A 0-minute duration disables the exercise cycle. This is used to keep the generator mechanically ready during long periods of non-use. Set a day, time, and duration to run the generator weekly for maintenance. Set duration to 0 minutes to disable.
Mon 08:00 — 0 min

Discharge

Two-column values (Voltage / SOC%) appear for thresholds. When BMS% mode is active, the % column governs.

Setting Value (V / %)
ShutDown
The battery voltage or SOC at which the inverter performs a controlled shutdown to protect the battery from deep discharge. Below this threshold, the inverter stops supplying load power and goes into standby. The battery must recover to the Restart threshold before the inverter will resume operation. Set too high, this wastes usable capacity; set too low, it risks battery damage. For LFP cells, 10–20% SOC is a common safe floor. For LFP banks, 10–20% SOC is a common safe floor. Verify with your battery manufacturer.
47.2V / 18%
Low Batt
Warning threshold below which the inverter displays a low battery alert and may adjust behavior (such as reducing discharge power or triggering a generator start). The inverter continues operating but alerts the user and monitoring system. Must be set above ShutDown. Set above ShutDown. 25–30% SOC is typical for a low battery warning.
47.8V / 25%
Restart
The voltage or SOC the battery must recover to before the inverter will restart after a ShutDown event. Adding a gap between Shutdown and Restart prevents rapid cycling (shutting down and immediately restarting) when the battery is hovering near the cutoff threshold. A gap of 5–10% SOC between ShutDown and Restart prevents rapid cycling.
50.0V / 27%
Batt Empty V
Absolute minimum battery voltage used as a hard safety cutoff. If the battery reaches this voltage, the inverter immediately stops all discharge. This value represents the hard floor below which battery damage is likely. For 48V LFP systems, 46.0V (approximately 2.875V/cell on a 16S pack) is near the true empty floor. Set below ShutDown.
46.0V
Batt Resistance
The estimated internal resistance of the battery bank in milliohms (mOhms). Used by the inverter to compensate for voltage sag under load when calculating true SOC from voltage. A lower resistance means less voltage drop under heavy discharge. For a large LFP bank, 5–15 mOhm is typical. An unusually high value causes the inverter to underestimate available capacity under load.
8 mOhms
Batt Charge Efficiency
The round-trip charge efficiency factor as a percentage. This accounts for the energy lost during the charge and discharge cycle. LFP is typically 97–99% efficient; lead-acid is closer to 80–85%. Set to 99.0% for LFP.
99.0%
BMS_Err_Stop
When checked, the inverter will stop operating if BMS communication is lost. This is a safety feature that prevents uncontrolled charging or discharging when the BMS can no longer protect the battery. Recommended for systems where the BMS is relied upon for protection (i.e., when open-circuit voltage protection thresholds are set more aggressively than the BMS would allow). The tradeoff is that a communication glitch can take down the whole system. Many installers leave this unchecked and rely on the inverter’s own voltage thresholds as backup protection.
OFF

Smart Load

Setting Value
Use Gen Input as Load Output
Routes generator AC power directly to the Load output terminals without inverter processing. This is a bypass mode that allows a generator to directly power backed-up loads. Useful when the inverter needs to be bypassed or when generator power should directly serve loads without conversion loss. Disable for standard solar-only configurations.
OFF
AC Coupled Input to Gen
Enables AC coupling of a grid-tie inverter through the GEN terminals of the Sol-Ark. When a string or micro-inverter is AC coupled to the GEN port, the Sol-Ark uses frequency shifting (raising frequency above 60Hz) to curtail the AC-coupled source when the battery is full. This prevents battery overcharge. The High Frz (62.00Hz) setting is the threshold at which the Sol-Ark begins frequency shift curtailment. Disable for standard solar-only configurations.
OFF
On Grid Always On
When enabled, the Smart Load output remains active whenever the utility grid is present, regardless of battery SOC. Typically used for non-critical loads that should only run when grid power is available (like a pool pump or water heater on a dedicated Smart Load circuit). Disable for standard solar-only configurations.
OFF
High Frz (Frequency Shift Threshold)
The frequency threshold above which the Sol-Ark begins frequency shifting to curtail an AC-coupled inverter connected to the GEN or Load terminals. When the battery reaches full charge, the Sol-Ark raises its output frequency above this value (62.00Hz here), which causes the grid-tie inverter to ramp down its output per Volt-Watt or Volt-Frequency response curves. This prevents the AC-coupled source from overcharging the battery. Only relevant when AC coupling is active.
62.00 Hz
Smart Load OFF Batt
The battery voltage or SOC at which the Smart Load output turns OFF. When the battery drops below this threshold, the inverter cuts power to the Smart Load circuit to preserve remaining capacity for essential loads. Typically set fairly low so that non-critical loads continue running as long as possible. Set to a low SOC floor so non-critical loads run as long as possible before being shed.
51.0V / 8%
Smart Load ON Batt
The battery voltage or SOC at which the Smart Load output turns back ON after having been shut off. Requires the battery to recover above this threshold before re-energizing the Smart Load circuit. The gap between OFF and ON thresholds prevents rapid cycling. Set higher than the OFF threshold to prevent rapid cycling.
54.0V / 44%
AC Couple on Grid Side / Load Side
Tells the Sol-Ark where the AC-coupled inverter is wired: on the Grid side (between the Sol-Ark GRID terminals and the utility meter) or on the Load side (between the Sol-Ark LOAD terminals and the backed-up load panel). The selection affects how the Sol-Ark calculates power flow and applies frequency shift control. Disable both when no AC-coupled inverter is connected.
Both OFF
Solar Power(W)
Minimum solar production threshold (watts) required before the Smart Load output is allowed to turn on. Prevents the Smart Load from consuming grid or battery power when solar production is negligible (cloudy day, early morning). The load only energizes when solar is generating at least this level, ensuring the connected loads run primarily on solar. Set to the minimum solar production level below which running the Smart Load load from solar is not meaningful.
500W

Wind Turbine

Not applicable for this installation. All values are at 0V / 0.0A (feature disabled).

Setting Value
DC1 / DC2 for Wind Turbine
Designates one or both of the Sol-Ark’s MPPT DC inputs as a wind turbine input instead of a PV input. When enabled, the associated input port uses the custom V1–V12 current/voltage curve below instead of standard MPPT tracking. The 12-point IV curve maps wind turbine output voltage to the expected charge current at that voltage, allowing accurate MPPT-style tracking of wind turbine output. Disable for solar-only installations.
Both OFF
V1–V12 / Current Curve
A 12-point lookup table defining the current vs. voltage characteristic of the connected wind turbine. Each point pairs a DC voltage (V) with an expected current (A) at that voltage. The inverter uses this curve to optimize power extraction from the turbine across its operating range. Leave all points at 0V / 0.0A when wind turbine input is not in use.
All 0V / 0.0A



3. Limiter Settings

System work modes, Time of Use schedule, and export/charging priority. This is the most-used programming area for day-to-day behavior. Access via System Setup → Limiter / Grid Setup → Limiter Param.

Work Modes & Export Limits (Limiter Tab)

Setting Value
Grid Sell
Enables selling excess solar power to the utility grid. When checked, any solar or battery power not needed for loads can be pushed out of the GRID terminals and credited under a net metering agreement. The numeric field (15000W = 15kW) sets the maximum export power limit. Many utilities cap export at a specific wattage as a condition of the net metering agreement. When unchecked, the Sol-Ark does not sell to the grid. Grid Sell must be enabled for the Sell column in the TOU table to function. Verify your net metering agreement before enabling.
OFF — 15000W limit
Limited Power to Home
When selected, the inverter uses the external CT sensors to monitor total home power consumption at the service entrance. Solar and battery power are used to offset the entire home load (including loads not connected to the Sol-Ark LOAD terminals), while preventing export to the grid. Best for systems where backup loads are in a sub-panel but the homeowner wants solar to offset the whole utility bill. Requires CT sensors on grid L1 and L2 leads. Disable for standard solar-only configurations.
OFF
Limited Power to Load
When selected, the inverter limits solar and battery power to serve only the loads connected to its LOAD terminals. No external CT sensors are required. All power leaving the GRID terminals is treated as “sold” in monitoring data. This is the correct mode for whole-home backup configurations where the utility meter feeds directly into the Sol-Ark GRID terminals and all home loads are on the LOAD terminals. Recommended for whole-home backup configurations.
ON
Time of Use (TOU)
Activates Time of Use scheduling. When enabled, the six-slot TOU table governs battery discharge depth, discharge power limits, and AC charging permissions for each time period throughout the day. TOU must be paired with either Limited Power to Load or Limited Power to Home to have effect. When TOU is off, batteries only discharge during grid outages (they stay fully charged while on-grid). Enable TOU and pair with either Limited Power to Load or Limited Power to Home for the TOU table to control battery behavior.
ON

Time of Use Schedule

Each row applies from its start time until the next row’s start time. All six slots must be programmed in ascending time order. Days and seasonal profiles are configured in the TOU Setup sub-dialog. The table below shows a typical configuration for a grid-tied system with TOU battery management.

Time Power (W) Batt % Charge Sell
1:00 AM 10,000 80%
5:00 AM 10,000 80%
9:00 AM 10,000 75%
1:00 PM 10,000 94%
5:00 PM 10,000 80%
9:00 PM 10,000 80%
Reading this TOU table: The Power(W) column limits how many watts the battery is allowed to discharge to cover loads in that time slot. The Batt% column is the SOC floor — batteries will not discharge below this level during that slot. The Charge column, when checked, permits grid charging during that slot (subject to the Grid Charge Start% threshold in Battery Settings). The Sell column permits selling battery power to the grid (Grid Sell must also be enabled). Setting Batt% to 100% in a slot effectively prevents battery discharge during that period — useful for preserving a full battery going into evening peak demand hours.

Other

Setting Value
GEN Connect to Grid Input
When checked, tells the inverter that the generator is wired to the GRID terminals instead of the dedicated GEN terminals. This is sometimes done when the generator is the only AC source and the installer wants to treat it as the “grid.” In this configuration, the inverter treats the generator as a utility-equivalent source for charging and load support. Must be set correctly to match the actual physical wiring. Enable only if the generator is physically wired to the GRID terminals rather than the dedicated GEN terminals.
ON
Zero-Export Power
A small intentional buffer (watts) that prevents the inverter from actually exporting to the grid while in zero-export mode. Because CT sensors have a small measurement lag, there is always a risk of brief inadvertent export. Setting this to 20W tells the inverter to target 20W of import rather than exactly 0W, ensuring the system stays on the import side of the meter at all times. A setting of 0W risks brief accidental export. 20–50W is a common practical value to prevent brief accidental export.
20W
Batt First
When checked, the inverter prioritizes using battery power before drawing from the grid when offsetting loads. This is the standard operating mode for most battery backup and TOU applications. Battery power is used first (up to TOU discharge limits), then solar, then grid. Enable for standard battery-backup and TOU operation.
ON
Load First
When checked, the inverter prioritizes satisfying load demand before sending energy to the battery. Load First and Batt First are mutually exclusive; selecting one disables the other. Load First is less common in residential applications. Disable when Batt First is selected; the two settings are mutually exclusive.
OFF



4. Grid Settings

Grid interconnection parameters including compliance standards, voltage/frequency windows, protection trip thresholds, and advanced grid support functions. These are set during commissioning per local utility requirements. Do not modify without utility or AHJ authorization. Access via System Setup → Limiter / Grid Setup → Grid Param.

Grid Selection

Setting Value
Grid Mode / Standard
Selects a pre-configured grid compliance profile. Navigation arrows cycle through available profiles (0/3 means profile 0 of 3 available). “General Standard” is a generic IEEE 1547 / UL 1741 compliant profile suitable for most US residential utility interconnections where a specific utility profile is not required. Other profiles may include utility-specific presets (e.g., FPL, Duke, PSEG). Selecting a profile automatically populates the voltage, frequency, and protection parameters in the Connect and IP tabs. General Standard is suitable for most US residential utility interconnections. Select a utility-specific profile if required.
General Standard
Grid Frequency
Selects the nominal grid frequency. 60Hz is standard for North America (US, Canada, Mexico). 50Hz is standard for most of Europe, Asia, Africa, and Australia. Must match the utility frequency. Incorrect selection will cause the inverter to fail grid synchronization. 60Hz for North America; 50Hz for most of Europe, Asia, and Australia.
60Hz
Phase Configuration
Selects the AC output configuration. Single Phase (120V only), 120/240V Split Phase (standard US residential with L1, L2, and Neutral), or 120/208V 3-Phase (commercial). The Sol-Ark 15K-P produces 120/240V split-phase natively and is the standard configuration for US residential whole-home backup. 120/240V Split Phase is standard for US residential whole-home backup.
120/240V Split Phase
Grid Reconnect Time
The mandatory wait period (seconds) before the inverter reconnects to the grid after a grid disturbance or outage. IEEE 1547 requires a minimum reconnect delay to allow the grid to stabilize after restoration. Default: 60 seconds. Some utilities require longer delays (up to 300 seconds). Do not reduce below what the utility specifies in the interconnection agreement.
60s
Power Factor
The target power factor for grid-connected operation. 1.000 = unity power factor (no reactive power injection). Most residential utility interconnections require unity power factor. Commercial installations with reactive power requirements from the utility may specify a non-unity target. 1.000 (unity) is required for most residential utility interconnections.
1.000
Fixed Q / Q_Response
Fixed Q sets a constant reactive power injection level (% of rated power). Q_Response sets the time constant for reactive power response changes (seconds). Both are advanced grid support parameters primarily used in utility-scale or utility-mandated smart inverter functions. For standard residential interconnections, Fixed Q = 0% (no reactive injection) and Q_Response = 10S are appropriate. For standard residential installations, leave at 0% / 10S unless the utility requires otherwise.
0% / 10S
Output V / Output V+
Output V is the nominal AC output voltage target (120/240V for US split-phase). Output V+ is a voltage offset trim that adjusts the actual output voltage up or down from nominal. A value of +0V means no offset is applied. This trim can be used to compensate for voltage drop in long wiring runs or to fine-tune inverter output voltage to match local utility voltage. 120/240V for standard US residential. Adjust Output V+ only to compensate for measured voltage drop in long wiring runs.
120/240V / +0V

Connect (Voltage & Frequency Windows)

Two sets of thresholds: Reconnect (tighter window, grid must be within these values before reconnecting) and Normal Connect (wider operating window, inverter disconnects if grid exceeds these).

Parameter Reconnect Normal
Grid Vol High
Maximum grid voltage for reconnection (tighter) or continued connection (wider). Grid must be below the Reconnect threshold for the inverter to re-synchronize after a disconnect event. Once connected, the inverter will disconnect if grid voltage exceeds the Normal Connect threshold. IEEE 1547 / Rule 21 define these limits by voltage class.
263.8V 288.0V
Grid Vol Low
Minimum grid voltage for reconnection or continued operation. Grid must be above the Reconnect threshold before the inverter will reconnect. If voltage drops below Normal Connect threshold, the inverter disconnects and enters backup mode.
211.4V 120.0V
Grid Hz High
Maximum grid frequency for reconnection or continued operation. Grid frequency must be below this value before or during grid connection.
64.0Hz 65.0Hz
Grid Hz Low
Minimum grid frequency for reconnection or continued operation.
56.0Hz 55.0Hz
Ramp Rate
How quickly the inverter ramps power output up after reconnecting (Reconnect Ramp rate) or during normal operation (Normal Ramp rate). Measured in seconds. A slower ramp rate is gentler on the grid and battery system; IEEE 1547-2018 and some utilities specify maximum ramp rates. 20s is the typical default.
20s 20s

IP (Instantaneous Protection — Voltage & Frequency Trip Thresholds)

HV = High Voltage trip levels. LV = Low Voltage trip levels. HF = High Frequency. LF = Low Frequency. Levels 1–2 have programmable trip times; Level 3 = instantaneous. These are anti-islanding and grid protection settings required by IEEE 1547 and UL 1741. Do not modify without utility authorization.

Level Threshold Trip Time
Over Voltage — Running Mean: 260.0V (10-min average)
HV3 (Instantaneous) 288.0V Instant
HV2 265.0V 0.10s
HV1 265.0V 0.10s
Under Voltage
LV1 185.0V 0.10s
LV2 185.0V 0.10s
LV3 (Instantaneous) 120.0V Instant
Over Frequency
HF3 (Instantaneous) 65.00Hz Instant
HF2 65.00Hz 0.10s
HF1 65.00Hz 0.10s
Under Frequency
LF1 55.00Hz 0.10s
LF2 55.00Hz 0.10s
LF3 (Instantaneous) 55.00Hz Instant

F(W) — Frequency-Watt Response

Advanced smart inverter function per IEEE 1547-2018. Adjusts real power output in response to grid frequency deviations. Required by some utilities for advanced interconnection. Values shown are defaults; do not modify without utility specification.

Parameter Over Freq. Under Freq.
Droop Rate 40%PE/Hz 40%PE/Hz
Start Frequency 50.20Hz 49.80Hz
Stop Frequency 50.20Hz 49.80Hz
Start Delay 0.00s 0.00s
Stop Delay 0.00s 0.00s

V(W)/V(Q) — Volt-Watt / Volt-VAR Response

Advanced smart inverter grid support functions per IEEE 1547-2018. V(W) reduces real power as voltage rises to help manage high-voltage events. V(Q) injects or absorbs reactive power to support grid voltage. Both are disabled by default for standard residential interconnection. Values shown are the factory default curves.

V(W) — Disabled — Response Time: 10S V(Q) — Disabled — L.in: 20.0% / L.out: 5.0%
Volt % Power % Volt % Q %
V1: 109.0% P1: 100% V1: 90.0% Q1: 44%
V2: 110.0% P2: 20% V2: 95.7% Q2: 0%
V3: 111.0% P3: 20% V3: 104.3% Q3: 0%
V4: 111.0% P4: 20% V4: 112.2% Q4: 60%

P(Q)/P(F) — Power-Reactive / Power-Frequency Response

Advanced grid support curves. P(Q) adjusts reactive power based on active power level. P(F) adjusts power factor based on active power level. Disable both when no AC-coupled inverter is connected. Default curves shown.

P(Q) — Disabled P(F) — Disabled — L.in: 50% / L.out: 100%
P % Q % P % PF
P1: 20% Q1: 20% P1: 50% F1: 0.000
P2: 100% Q2: 20% P2: 100% F2: 0.800
P3: 100% Q3: 20% P3: 100% F3: 0.800
P4: 100% Q4: 20% P4: 100% F4: 0.800



5. System Alarm Codes Reference

The System Alarms screen logs fault events with timestamps. Access via System Setup → System Alarms. This is a complete reference for all fault codes documented in the Sol-Ark 5K/8K/12K/15K manual and official troubleshooting guide. Click any code to expand causes and resolution steps. Codes marked 🛠 require service action; codes marked are typically self-clearing.

How to read the alarm log: Navigate to System Setup → System Alarms. Faults are listed in reverse chronological order with a timestamp. Multiple occurrences of the same code on the same day indicate an intermittent or recurring condition. When troubleshooting, always identify the first fault in a sequence — cascade faults like F41 (Parallel_System_Stop) are symptoms of an earlier triggering fault, not root causes.
Code Fault Name & Description
F01
DC_Inversed_Failure

The inverter detected reversed DC polarity or no DC voltage at startup. In parallel systems, this code also appears on slave units as a notification when the master is powered off and a slave initializes without seeing the expected DC bus.

Common causes: Battery terminals connected with reversed polarity; battery breaker open at startup; battery voltage too low to initialize the inverter; BMS tripped and disconnected mid-operation; loose DC battery cable connections.

Resolution: Verify battery positive and negative terminal polarity. Confirm all battery breakers are closed before powering up. Measure battery voltage at the inverter DC terminals. In parallel systems, note this is a notification when one unit is off — not a true fault requiring action.

F02
DC_Insulation_Failure

Insulation resistance between the DC side (PV or battery) and ground has dropped below the safe threshold. This is a ground fault on the DC side of the system and is a safety-critical fault.

Common causes: Damaged or pinched PV wire with the conductor touching a grounded surface; water intrusion into a junction box or MC4 connector; failed insulation on battery cable contacting the enclosure.

Resolution: Disconnect PV strings one at a time and re-test to isolate the faulted string. Inspect all MC4 connectors and junction boxes for moisture, damage, or cracking. Check battery cables for insulation damage. Do not continue operating until the fault source is identified and corrected.

F03
GFDI_Failure

Ground Fault Detection and Interruption circuit failure. The GFDI circuit monitors for DC ground faults per NEC 690.5. This code indicates the GFDI detection circuitry itself has identified a fault condition or self-test failure.

Common causes: PV wiring ground fault (positive or negative conductor contacting ground); moisture in PV wiring; a grounded PV conductor anywhere in the array.

Resolution: Check all PV wiring for ground contact. Inspect array wiring and conduit for moisture entry. Contact Sol-Ark support if the fault persists after verifying wiring.

F04
GFDI_Ground_Failure

A specific ground fault on the GFDI monitoring circuit. Similar to F03 but indicates a fault at the ground reference point rather than in the detection electronics.

Common causes: PV wiring touching a grounded metal surface; grounded negative or positive PV conductor.

Resolution: Inspect all PV string wiring. Disconnect strings individually to isolate the faulted circuit. Contact Sol-Ark support if issue persists after wiring verification.

F05
EEPROM_Read_Failure

The inverter’s non-volatile memory (EEPROM) failed to read stored configuration data at startup. This is an internal hardware or firmware fault.

Common causes: Firmware corruption from a failed update; hardware failure of the memory chip; power interruption during a settings write operation.

Resolution: Attempt a factory reset (Basic Setup → Factory Reset). If the fault persists, contact Sol-Ark support — this typically requires a firmware reload or board replacement.

F06
EEPROM_Write_Failure

The inverter failed to write configuration data to non-volatile memory. Settings changes made by the user may not have been saved.

Common causes: Power interruption during a settings write; hardware memory failure; firmware issue.

Resolution: Power cycle the inverter fully and re-enter settings. Contact Sol-Ark support if the fault recurs — persistent write failures indicate a hardware problem.

F07
GFDI_Fuse_Failure

The internal GFDI protection fuse has blown or failed. This fuse is part of the ground fault protection circuitry. Once blown, ground fault protection is compromised.

Common causes: A DC ground fault caused excessive current through the GFDI fuse; hardware failure.

Resolution: Contact Sol-Ark support. Internal fuse replacement is required and should not be attempted in the field without factory guidance.

F08
GFDI_Relay_Failure

The GFDI relay failed to operate correctly. This relay is responsible for disconnecting the circuit when a ground fault is detected. A leakage current from the inverter AC output to ground can trigger this code.

Common causes: Current leakage from the inverter AC output to ground; neutral and ground not properly bonded at the main panel; hardware relay failure.

Resolution: Verify that neutral and ground are bonded at the main service panel (and only there — double bonding causes problems). Check AC wiring for insulation damage. Contact Sol-Ark support if the relay itself has failed.

F09
IGBT_Failure

One or more of the main power switching transistors (IGBTs) inside the inverter has failed. IGBTs are the core power conversion components; this is a significant hardware failure.

Common causes: Overtemperature from inadequate ventilation; sustained overload beyond rated capacity; lightning or surge damage; end of life on high-cycle systems.

Resolution: Contact Sol-Ark support. IGBT replacement is a factory or authorized service repair. Do not attempt to restart the inverter repeatedly after this fault as further damage may occur.

F10
AuxPowerBoard_Failure

The auxiliary power supply board, which powers the inverter’s control electronics and gate drivers, has failed or is not delivering correct voltages.

Common causes: Hardware failure of the auxiliary board; power surge; age-related component failure.

Resolution: Contact Sol-Ark support. This is a hardware repair requiring factory or authorized service. Do not continue to power cycle the unit.

F11
AC_MainContactor_Failure

The main AC relay (contactor) that connects and disconnects the inverter from the grid or load did not operate correctly. This relay is what enables sub-10ms backup transfer time.

Common causes: Relay contact wear or sticking; hardware failure; power surge damaging the relay coil or contacts.

Resolution: Contact Sol-Ark support. AC contactor replacement requires factory or authorized service repair.

F12
AC_SlaveContactor_Failure

The secondary AC relay (slave contactor) failed to operate correctly. This relay works in conjunction with the main contactor for AC switching operations.

Common causes: Same as F11. Relay contact wear, sticking, or coil failure.

Resolution: Contact Sol-Ark support. Factory or authorized service repair required.

F13 ↻
Working_Mode_change (Notification)

This is a notification, not a fault. It is logged when the inverter’s operating mode changes — for example when transitioning between on-grid and off-grid, or when a settings change alters the work mode. It also appears when a system configured without a battery switches to battery mode.

Common causes: Grid loss or restoration causing mode transition; manual settings change while the system is running; switching from No Battery to Battery mode.

Resolution: No action required in most cases. If switching from No Battery to Battery mode, perform a full power-down restart to ensure the inverter properly initializes in the new configuration.

F14
DC_OverCurr_Failure

DC current from the battery or PV input exceeded the hardware overcurrent protection threshold. This is a fast hardware trip.

Common causes: Extremely large load causing high battery discharge current; more than two PV strings wired in parallel on a single MPPT exceeding the 26A limit; DC short circuit on the battery side.

Resolution: Reduce load on the system. Verify PV string configuration does not exceed two strings per MPPT. Inspect DC wiring for short circuits or loose connections. If the fault recurs without an obvious cause, contact Sol-Ark support.

F15
AC_OverCurr_Failure

AC output current exceeded the inverter’s hardware protection limit. The inverter tripped to protect its internal components. Related overload faults include F18, F20, and F26.

Common causes: Total connected load exceeds inverter rating (15kW continuous, 12kW battery-only); single large load such as a 4+ ton AC unit, large motor, or welder; Max A Discharge setting is too low for the load demand in off-grid mode; short circuit on the load side.

Resolution: Identify and reduce the overloading load. In off-grid mode, verify Max A Discharge is set high enough for peak loads. Check for AC wiring shorts. If the fault occurs on startup of a motor load, it may be a normal inrush — verify the motor starts cleanly when powered directly from the grid.

F16
GFCI_Failure

Ground fault current was detected on the AC output side. The AC GFCI protection circuit tripped. Exposed PV conductors combined with moisture can trigger this fault alongside F24 and F26.

Common causes: PV+ or PV- conductor touching a grounded surface; neutral and ground double-bonded somewhere in the system (common with portable generators connected to the GEN terminal); water in a load-side conduit or J-box; defective GFCI outlet or breaker on the load panel causing leakage current.

Resolution: Verify PV wiring is ungrounded. Confirm neutral-ground bond exists only at the main service panel. Disconnect the generator if connected and retest. Isolate circuits on the load panel one at a time if needed to find the leaking circuit.

F17
Tz_COM_OC_Fault

An overcurrent condition was detected on the internal communication bus between control boards. This is an internal electronics fault.

Common causes: Internal hardware fault; EMP or surge damage to communication circuitry.

Resolution: Contact Sol-Ark support. This code is not field-repairable.

F18
Tz_Ac_OverCurr_Fault

AC overcurrent detected at the software/firmware level (as opposed to the hardware trip in F15). The inverter’s firmware detected an AC current overload and shut down. Overloads can cascade to F15, F18, F20, and F26. Phase imbalance from incorrect wiring in 120/208V three-phase applications (Grid Phase Wrong) can also trigger F18 even with no load connected.

Common causes: Loads too large for the inverter; generator overloaded (reduce Gen Start A); AC wiring short on the load side; phase sequencing error in parallel/3-phase systems.

Resolution: Reduce load. Verify Gen Charge A is not overloading the connected generator. Check for AC wiring shorts. In parallel or 3-phase systems, verify correct phase wiring — the “Grid Phase Wrong” condition will cause F18 even with the LOAD breaker off.

F19
Tz_Integ_Fault

An integration fault in the power conversion control loop. This is a firmware-level fault indicating an abnormal condition in the internal inverter control math.

Common causes: Sustained overload condition; hardware fault in the power conversion stage; firmware bug.

Resolution: Power cycle the inverter. If the fault recurs, contact Sol-Ark support.

F20
Tz_Dc_OverCurr_Fault

Software-level DC overcurrent fault in the power conversion stage. Typically caused by peak DC current from the battery exceeding the inverter’s control limits under high-demand conditions. Grounded PV wiring can also cause F20, F23, or F26.

Common causes: Very large loads such as a 4+ ton AC unit drawing high inrush current; more than two PV strings in parallel on a single MPPT; grounded PV conductor.

Resolution: Identify the high-demand load. Verify PV string count does not exceed two per MPPT. Check PV wiring for grounding issues.

F21
Tz_GFDI_OC_Fault

Overcurrent detected in the GFDI (Ground Fault Detection and Interruption) monitoring circuit. An excessive ground fault current triggered this protection.

Common causes: Significant DC-side ground fault; damaged PV insulation causing current to flow to ground.

Resolution: Inspect all PV wiring and array connections for insulation damage. Isolate PV strings to identify the faulted circuit.

F22
Tz_EmergStop_Fault

Emergency stop was triggered. The inverter received a signal on the emergency stop input (pins B and B on the sensor pinout) to shut down AC output and initiate PV rapid shutdown.

Common causes: Emergency stop button pressed or wired; short circuit or fault in the emergency stop wiring; water or debris causing a momentary short across the stop pins.

Resolution: Verify the emergency stop circuit is open (normal state). Inspect the wiring to pins B and B. If no button is installed, confirm those pins are not shorted.

F23
Tz_GFCI_OC_Fault

PV ground fault detected by the GFCI overcurrent circuit. A PV conductor (positive or negative) is grounding through the chassis or earth path. Grounded PV wiring can cause F20, F23, or F26 in combination.

Common causes: Pinched PV wire with conductor contacting a grounded metal surface; water in a conduit or junction box causing a conductive path to ground; old PV wiring with degraded insulation.

Resolution: PV+ and PV- must remain ungrounded at all times. Inspect all string wiring for pinch points, conduit entry damage, or aging insulation. Replace any damaged wire sections. If the array was recently grounded for other work, verify that ground path has been removed.

F24
DC_Insulation_Fault

DC insulation resistance to ground has fallen below the minimum acceptable level. This is a potential earth fault on the PV side and is a safety-critical condition. Exposed PV conductors combined with moisture commonly trigger F16, F24, and F26 together.

Common causes: PV wiring with damaged insulation in contact with moisture; cracked or abraded MC4 connector bodies; water intrusion into a junction box or conduit.

Resolution: This fault must be cleared before returning to operation. Use a megohmmeter to test insulation resistance on each string. Isolate and replace any damaged wiring. Dry out and seal all wet junction boxes and conduit entries.

F25
AC_Active_Batt_Fault

The inverter has “Activate Battery” enabled but no battery is connected or detected. The inverter cannot complete its initialization without seeing a battery when this setting is active.

Common causes: Battery breaker left open; battery cable disconnected; BMS tripped and disconnected the battery; “Activate Battery” is checked when running a battery-less grid-tie configuration.

Resolution: If a battery is installed, verify all breakers are closed and battery cables are secure. If this is intentionally a grid-tie only system with no battery, go to Battery Setup and uncheck “Activate Battery.”

F26
BusUnbalance_Fault

The DC bus voltage between L1 and L2 halves is significantly unbalanced. In 120/240V split-phase operation, the inverter produces two 120V legs referenced to neutral. If one leg is loaded much more heavily than the other, the DC bus midpoint shifts, causing this fault.

Common causes: Significant load imbalance between L1 and L2 — for example, most heavy loads running on one phase; DC-powered devices connected to the AC output in off-grid mode; grounded PV wiring (can cause F20, F23, and F26 together); phase wiring errors in parallel or three-phase systems (Grid Phase Wrong also triggers F26 and F34).

Resolution: Balance loads more evenly between L1 and L2. In off-grid mode, verify no DC loads are connected to AC output circuits. Check PV wiring for grounding. In parallel systems, verify phase wiring is correct on all inverters before connecting loads.

F29
Parallel_CANBus_Fault

Loss of CANbus communication between parallel-connected Sol-Ark units. The Master expects continuous data from all Slave units. When communication drops, the system halts parallel operation to prevent unsynchronized output. F29 and F41 will both appear momentarily when inverters are powered up sequentially in a parallel system — this is normal and self-clears once all units are online.

Common causes: Wrong type of communication cable (must be CAT5E or better, straight-through); loose or damaged RJ45 connector; duplicate Modbus SN assignments; one unit powered off while others remain active; firmware version mismatch between units.

Resolution: Verify CAT5E or better cable is used for parallel communication. Check RJ45 connectors for damaged pins. Confirm each unit has a unique Modbus SN (Master = 01, Slaves = 02, 03, etc.). Ensure all units are running the same firmware version.

F30
AC_MainContactor_Fault

Similar to F11, the main AC contactor failed to operate. This code appears as the firmware-level detection of the same hardware fault.

Common causes: Relay contact failure; power surge damage; hardware wear.

Resolution: Contact Sol-Ark support. Requires factory or authorized service repair.

F31
Soft_Start_Failed

The soft-start sequence for a large motor load failed. The inverter attempts a controlled ramp-up of voltage/current when starting large inductive loads; if the load does not start cleanly within that window, this fault is generated.

Common causes: Load motor is too large for the inverter’s peak output capacity; motor is seized or mechanically jammed; load was already running when the inverter tried to connect; locked rotor current exceeds inverter peak rating.

Resolution: Verify the motor can start cleanly when powered directly from utility. Size the inverter appropriately for the motor’s LRA (locked rotor amps). Consider adding a soft-starter or VFD upstream of large motor loads if the inrush is problematic.

F34
AC_Overload_Fault

AC output is overloaded. The inverter is being asked to supply more power than its continuous rating. Phase wiring errors (Grid Phase Wrong) in parallel or three-phase systems can trigger F18, F26, and F34 even with the LOAD breaker open.

Common causes: Total connected load exceeds inverter output rating; a load shorted; phase wiring error in parallel/3-phase systems.

Resolution: Reduce total load. Check for load-side short circuits. In parallel or three-phase systems, verify phase wiring is correct before connecting any loads — measure L1-to-L1 and L2-to-L2 between units and to the panel, expecting 0V AC on matched phases.

F35 ↻
AC_NoUtility_Fault (Self-Clearing)

Grid connection was lost. The inverter disconnected from the utility and switched to backup/off-grid mode. This code logs whenever a utility outage occurs and is self-clearing when the grid is restored and the reconnect timer expires.

Common causes: Utility outage; main breaker tripped; disconnect switch opened; grid voltage or frequency went outside the Normal Connect thresholds.

Resolution: No action required if this corresponds to a real outage event. If it appears during normal utility availability, check grid voltage and frequency at the inverter GRID terminals. Verify the Normal Connect thresholds in Grid Param → Connect are appropriate for your local utility.

F37
DCLLC_Soft_Over_Cur

Software-level overcurrent detected in the DC-DC LLC (resonant) converter stage — the internal DC bus converter that steps voltage between the battery and the high-voltage DC bus.

Common causes: Sustained overload; battery voltage at the low end of operating range causing the LLC to draw more current; hardware fault in the DC conversion stage.

Resolution: Reduce load. Verify battery voltage is within the 43–63V operating range. If the fault recurs at normal load levels, contact Sol-Ark support.

F39
DCLLC_Over_Current

Hardware-level overcurrent trip in the DC-DC LLC converter. This is the hardware protection layer for the same subsystem monitored by F37.

Common causes: Severe overload; hardware fault in the DC conversion stage; extremely low battery voltage forcing excessive step-up current.

Resolution: Same as F37. If this occurs repeatedly at normal load with normal battery voltage, contact Sol-Ark support as it indicates a hardware problem.

F40
Batt_Over_Current

Battery discharge current exceeded the programmed Max A Discharge limit or the battery’s own BMS discharge current limit. The inverter throttled or shut down to protect the battery.

Common causes: Load demand exceeds Max A Discharge setting; battery BMS reported an overcurrent condition; very large inrush load starting off-grid.

Resolution: Review Max A Discharge setting and increase if the battery can safely support higher current. Verify the BMS discharge current limit is configured appropriately. Reduce peak loads or add battery capacity if the bank is undersized for demand.

F41 ↻
Parallel_System_Stop (Cascade — Self-Clearing)

In a parallel system, one unit faulted and caused the entire group to stop. This code appears on all units in the group that were running normally when the triggering unit faulted. F41 is always a cascade fault — it is never the root cause. F29 and F41 will both appear momentarily on startup when parallel units come online sequentially; this is normal and self-clears. If the system faults five consecutive times, it stops completely and requires a manual restart.

Common causes: Any fault on any parallel unit (most commonly F29 CANBus fault, F01 DC Inversed, or an overload fault) that causes one unit to shut down, cascading to all others.

Resolution: Identify the root cause fault in the alarm log — it will appear before F41 in chronological order. Clear the root cause first. After the root cause is resolved, all units will restart automatically unless the five-fault consecutive limit was reached, in which case perform a full power cycle on all units.

F45 ↻
AC_UV_OverVolt_Fault (Self-Clearing)

Grid voltage dropped below the programmed Normal Connect low voltage threshold, causing the inverter to disconnect. The inverter will automatically reconnect once voltage returns within range and the reconnect timer expires.

Common causes: Utility undervoltage event or sag; extended utility outage; undersized utility transformer; loose or corroded neutral at the service entrance.

Resolution: This is self-clearing. If it occurs frequently, log the grid voltage over time using MySolArk monitoring to document the utility power quality issue. A loose neutral at the service entrance can cause wildly fluctuating voltage on one leg and should be investigated with the utility.

F46
Parallel_Aux_Fault

A parallel-connected unit cannot communicate with the other units in the group. This is distinct from F29 in that it specifically indicates the auxiliary communication channel has failed.

Common causes: Incorrect Modbus SN assignments; Master not set to 01; Slaves not set to 02–09; communication cable not connected or defective.

Resolution: Verify Modbus SN assignments: Master must be 01, Slaves must be 02, 03, etc. (not 1, 2, 3). Check that CAT5E or better cables are connected to the correct parallel RJ45 ports on all units.

F47 ↻
AC_OverFreq_Fault (Self-Clearing)

Grid frequency exceeded the Normal Connect high frequency threshold (default 65Hz). The inverter disconnected as required by anti-islanding protection. This is common during and immediately after utility outages when the grid is transitioning or when a generator produces slightly high frequency. Self-resets when frequency stabilizes.

Common causes: Generator with high frequency output connected to the GRID terminal; utility frequency transient during outage restoration; incorrect generator frequency settings.

Resolution: This is self-clearing. If it occurs consistently with a connected generator, verify the generator’s output frequency. Set the grid mode to “General Standard” and widen the frequency range to 55–65Hz for better generator compatibility.

F48 ↻
AC_UnderFreq_Fault (Self-Clearing)

Grid frequency dropped below the Normal Connect low frequency threshold (default 55Hz). The inverter disconnected. Common during utility outages and self-resets when frequency stabilizes.

Common causes: Utility under-frequency event; overloaded generator producing low frequency; utility restoration transient.

Resolution: Self-clearing. For generator use, verify the generator is not being overloaded — a generator running above its rated load will drop in frequency. Widen the frequency range in Grid Param → Connect to 55–65Hz for better generator compatibility.

F55
DC_VoltHigh_Fault

The DC bus voltage exceeded the maximum safe operating level. On the PV side, this means the array open-circuit voltage exceeded 500V. On the battery side, it means the battery voltage exceeded the maximum (59V on standard models, 63V on extended range models).

Common causes: PV string voltage exceeds 500Voc at cold temperatures — always perform temperature-corrected Voc calculations for the coldest expected ambient temperature; battery charger or BMS malfunction causing overcharge; incorrect charger settings leading to overvoltage.

Resolution: For PV, recalculate string Voc at the lowest expected ambient temperature (use NEC 690.7 temperature correction). Reduce string length if needed. For battery, verify charge settings (Absorption V, Float V) are within the battery manufacturer’s specified range. Check for BMS faults.

F56
DC_VoltLow_Fault

The DC bus (battery) voltage fell below the minimum operating threshold. The inverter shut down to protect the battery from damaging deep discharge. Can also be triggered when the inverter is in off-grid mode and the battery discharge current exceeded the Max A Discharge setting by 20%, or when the BMS has disconnected the battery pack.

Common causes: Battery depleted during extended grid outage; ShutDown voltage/SOC set too low allowing the battery to drop too far; battery undersized for the load during an outage; BMS protective disconnect; loose battery connection causing a momentary voltage drop under load.

Resolution: Review ShutDown and Low Batt voltage/SOC thresholds. Inspect battery connections for resistance. Check battery SOH via the Li-Batt Info screen. Consider adding battery capacity if the bank is regularly depleting during outages. Check BMS status if a BMS-equipped battery is installed.

F58
BMS_Communication_Fault

The inverter is configured for closed-loop BMS communication (BMS Lithium Batt is enabled) but cannot establish or maintain communication with the battery BMS. If BMS_Err_Stop is enabled, the inverter will halt operation when this fault occurs.

Common causes: Wrong BMS protocol selected (verify the correct two-digit BMS mode number for your battery brand); incorrect RJ45 cable wiring or wrong port used; BMS powered off or battery breaker open; damaged CANBus cable; firmware mismatch between BMS and inverter.

Resolution: Verify the BMS Lithium Batt protocol code matches your battery brand per the Sol-Ark Battery Integration Guide (sol-ark.com/battery-partners). Confirm the cable is connected to the Battery CANBus port (not the parallel RS485 port). Check that the battery is powered on. Verify cable wiring matches the RJ45 pinout for CANBus or RS485 as appropriate for your battery.

F60 ↻
Gen_Volt_or_Fre_Fault (Self-Clearing)

The generator’s voltage or frequency output went outside the acceptable operating range and the inverter disconnected from the generator. Self-clears when generator output stabilizes.

Common causes: Generator overloaded causing frequency droop; generator warming up and voltage/frequency not yet stable; governor or AVR (automatic voltage regulator) issue on the generator; THD too high on an older or lower-quality generator.

Resolution: Reduce the load on the generator during startup. Allow the generator to warm up fully before the inverter connects. If the fault is chronic, select “General Standard” grid mode and widen the frequency range to 55–65Hz and voltage range to 185–263V for better generator tolerance. Verify generator output with a true RMS meter under loaded conditions.

F61
Button_Manual_OFF

A Slave unit in a parallel system was manually powered off without first powering off the Master. In parallel systems, the Master controls the group — turning off a Slave without shutting down the system first can cause instability and this fault.

Common causes: Someone pressed the power button on a Slave inverter while the Master was still running; a power interruption to one unit only.

Resolution: Always power down a parallel system starting with the Master first. To restart, power on the Slaves first and then the Master, or power all units on simultaneously. Review the parallel systems startup sequence in the installation manual (Section 5.2).

F63 🛠
ARC_Fault

An arc fault signature was detected on one or more of the MPPT PV inputs. This code only appears when Solar Arc Fault ON is enabled in Basic Setup → Advanced. The arc fault algorithm monitors PV input current waveforms for signatures consistent with a series arc fault in DC wiring. An arc in a DC circuit is a potential fire hazard and should be investigated before resuming operation. This fault must be manually cleared each time it occurs using Clear Arc Fault in the Advanced settings.

Common causes: Loose, damaged, or improperly crimped MC4 connector creating an intermittent connection; chafed or pinched PV wire with conductor partially exposed; failed or cracked PV junction box; wiring damaged by rodents, animals, or mechanical abrasion; false triggers are possible near powerful lightning storms or when using Tigo or other DC optimizers (some optimizer types are not compatible with the arc fault algorithm — if using optimizers, disable arc fault detection).

Resolution: Inspect all PV string wiring and MC4 connectors for physical damage. Test each string’s Isc and Voc to verify normal output. Use a DC clamp meter to check for abnormal current signatures. Replace any damaged connectors or wire sections. Do not repeatedly clear the fault without investigation — a series arc in a DC circuit can ignite surrounding materials.

F64
Heatsink_HighTemp_Fault

The inverter’s heatsink temperature reached the shutdown threshold. The inverter shuts down to prevent thermal damage to the power electronics. Note that the inverter begins derating output at 45°C ambient temperature and shuts down at 82°C heatsink temperature (AC side) or 100°C (DC side).

Common causes: Internal cooling fans not spinning or seized; inadequate clearance around the inverter (minimum 6 inches vertical, 2 inches side clearance required); inverter installed in a confined space or enclosure without ventilation; extremely high ambient temperature; inverter running at maximum output continuously in hot weather; debris or dirt blocking the fan intake.

Resolution: Power down the inverter and allow it to cool. Inspect the built-in fans — spin them manually to check for bearing seizure; replace fans if not spinning freely. Clear any obstructions from the air intake and exhaust areas. Verify installation clearances are met. Consider a ventilated enclosure or shade cover if ambient temperatures regularly exceed 45°C.

Applies to Sol-Ark 5K, 8K, and 15K-P inverters. For the latest documentation visit sol-ark.com/resources. Settings and screen layout may vary slightly by firmware version.

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