enyo SunSpec SDK

SunSpec Modbus client for reading data from solar inverters, batteries, meters, and other energy devices over Modbus TCP/RTU.

Table of Contents

• How Addressing Works
• Bulk Register Reading
• Data Types
• Scale Factors
• Model 1 — Common Block
• Model 101 — Single-Phase Inverter
• Model 103 — Three-Phase Inverter
• Model 121 — Inverter Settings
• Model 123 — Inverter Controls
• Model 124 — Battery Basic Storage Controls
• Model 160 — MPPT
• Models 201/203/204 — Meters
• Model 802 — Battery Base
• Writable Registers
• Enum Reference

How Addressing Works

Base Address Detection

SunSpec devices expose a "SunS" identifier at a known base address. The SDK auto-detects:

| Mode | Base Address | "SunS" Location | First Model Address | |------|-------------|-------------------|---------------------| | 1-based (most common) | 40001 | 40001–40002 | 40003 | | 0-based | 40000 | 40000–40001 | 40002 | | Custom | user-provided | user-provided | base + 2 |

Model Discovery

Starting from the first model address, the SDK scans through contiguous model blocks:

┌──────────────┬──────────────┬─────────────────────────┐
│ Model ID     │ Model Length │ Model Data Registers    │
│ (1 register) │ (1 register) │ (Length registers)      │
├──────────────┼──────────────┼─────────────────────────┤
│ offset 0     │ offset 1     │ offset 2 ... Length+1   │
└──────────────┴──────────────┴─────────────────────────┘
         ▲                              ▲
    model.address               model.address + 2

• model.address — Modbus address of the model ID register (start of the 2-register header)
• model.length — Number of data registers (does NOT include the 2-register header)
• Next model — Located at model.address + 2 + model.length
• End marker — Model ID 0xFFFF (65535) signals end of model chain

Register Offsets

All register offsets in this document are relative to model.address:

• Offset 0 = Model ID register
• Offset 1 = Model Length register
• Offset 2 = First data register (for most models)

Bulk Register Reading

Each model is read in a single Modbus call via readModelBlock(), which reads model.length + 2 contiguous registers starting at model.address. Individual fields are then extracted from the resulting buffer — no additional network round trips.

Data Types

| Type | Registers | Bytes | Description | |------|-----------|-------|-------------| | uint16 | 1 | 2 | Unsigned 16-bit integer | | int16 | 1 | 2 | Signed 16-bit integer (two's complement) | | uint32 | 2 | 4 | Unsigned 32-bit integer (big-endian) | | acc32 | 2 | 4 | 32-bit accumulator (unsigned, monotonically increasing) | | string | N | 2N | UTF-8 string, null-padded | | enum16 | 1 | 2 | Enumerated value (uint16) | | enum32 | 2 | 4 | Enumerated value (uint32) | | bitfield16 | 1 | 2 | Bit flags (uint16) | | bitfield32 | 2 | 4 | Bit flags (uint32) |

NOT_IMPLEMENTED Sentinel Values

Registers may return sentinel values indicating the field is not implemented:

| Type | Sentinel Value | Hex | |------|---------------|-----| | int16 | -32768 | 0x8000 | | uint16 | 65535 | 0xFFFF | | int32 | -2147483648 | 0x80000000 | | uint32 | 4294967295 | 0xFFFFFFFF | | enum16 / bitfield16 | 65535 | 0xFFFF | | enum32 / bitfield32 | 4294967295 | 0xFFFFFFFF | | acc16 | 0 | 0x0000 (NOT_ACCUMULATED) | | acc32 | 0 | 0x00000000 (NOT_ACCUMULATED) | | string | all NULLs | 0x0000 per register |

Scale Factors

Many numeric fields have an associated scale factor (SF) register. The final value is:

scaled_value = raw_value × 10^SF

Scale factor registers are int16 and typically contain values like -2, -1, 0, 1, 2.

For example: raw value 2345 with SF -1 → 2345 × 10⁻¹ = 234.5

Model 1 — Common Block

Method: readCommonBlock()

| Offset | Field | Type | Qty | Description | |--------|-------|------|-----|-------------| | 0 | ID | uint16 | 1 | Model ID (= 1) | | 1 | L | uint16 | 1 | Model length (typically 65–66) | | 2–17 | Mn | string | 16 | Manufacturer name | | 18–33 | Md | string | 16 | Model name | | 34–41 | Opt | string | 8 | Options | | 42–49 | Vr | string | 8 | Firmware version | | 50–65 | SN | string | 16 | Serial number | | 66 | DA | uint16 | 1 | Modbus device address |

Model 101 — Single-Phase Inverter

Method: readSinglePhaseInverterData()

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 6 | A_SF | int16 | Current SF | | 10 | W_SF | int16 | Power SF | | 12 | Hz_SF | int16 | Frequency SF | | 13 | V_SF | int16 | Voltage SF | | 18 | DCA_SF | int16 | DC current SF | | 19 | DCV_SF | int16 | DC voltage SF | | 21 | DCW_SF | int16 | DC power SF |

Data Registers

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 2 | A | uint16 | A_SF | AC current (A) | | 7 | PhVphA | uint16 | V_SF | Phase voltage AN (V) | | 9 | W | int16 | W_SF | AC power (W) | | 11 | Hz | uint16 | Hz_SF | Frequency (Hz) | | 14 | DCA | uint16 | DCA_SF | DC current (A) | | 15 | DCV | uint16 | DCV_SF | DC voltage (V) | | 20 | DCW | int16 | DCW_SF | DC power (W) | | 24 | St | uint16 | — | Operating state (enum) |

Model 103 — Three-Phase Inverter

Method: readInverterData()

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 6 | A_SF | int16 | Current SF | | 13 | V_SF | int16 | Voltage SF | | 15 | W_SF | int16 | Power SF | | 17 | Hz_SF | int16 | Frequency SF | | 19 | VA_SF | int16 | Apparent power SF | | 21 | VAr_SF | int16 | Reactive power SF | | 23 | PF_SF | int16 | Power factor SF | | 26 | WH_SF | int16 | Energy SF | | 28 | DCA_SF | int16 | DC current SF | | 29 | DCV_SF | int16 | DC voltage SF | | 31 | DCW_SF | int16 | DC power SF | | 36 | Tmp_SF | int16 | Temperature SF |

Data Registers

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 2 | A | uint16 | A_SF | Total AC current (A) | | 3 | AphA | uint16 | A_SF | Phase A current (A) | | 4 | AphB | uint16 | A_SF | Phase B current (A) | | 5 | AphC | uint16 | A_SF | Phase C current (A) | | 7 | PPVphAB | uint16 | V_SF | Line voltage AB (V) | | 8 | PPVphBC | uint16 | V_SF | Line voltage BC (V) | | 9 | PPVphCA | uint16 | V_SF | Line voltage CA (V) | | 10 | PhVphA | uint16 | V_SF | Phase voltage AN (V) | | 11 | PhVphB | uint16 | V_SF | Phase voltage BN (V) | | 12 | PhVphC | uint16 | V_SF | Phase voltage CN (V) | | 14 | W | int16 | W_SF | AC power (W) | | 16 | Hz | uint16 | Hz_SF | Frequency (Hz) | | 18 | VA | uint16 | VA_SF | Apparent power (VA) | | 20 | VAr | int16 | VAr_SF | Reactive power (VAr) | | 22 | PF | int16 | PF_SF | Power factor | | 24–25 | WH | acc32 | WH_SF | Cumulative energy (Wh) | | 27 | DCA | uint16 | DCA_SF | DC current (A) | | 28 | DCV | uint16 | DCV_SF | DC voltage (V) | | 30 | DCW | int16 | DCW_SF | DC power (W) | | 32 | TmpCab | int16 | Tmp_SF | Cabinet temperature (°C) | | 34 | TmpSnk | int16 | Tmp_SF | Heat sink temperature (°C) | | 35 | TmpTrns | int16 | Tmp_SF | Transformer temperature (°C) | | 36 | TmpOt | int16 | Tmp_SF | Other temperature (°C) | | 38 | St | uint16 | — | Operating state (enum) | | 39 | StVnd | uint16 | — | Vendor-specific state | | 40–41 | Evt1 | bitfield32 | — | Event flags 1 | | 42–43 | Evt2 | bitfield32 | — | Event flags 2 | | 44–45 | EvtVnd1 | bitfield32 | — | Vendor events 1 | | 46–47 | EvtVnd2 | bitfield32 | — | Vendor events 2 | | 48–49 | EvtVnd3 | bitfield32 | — | Vendor events 3 | | 50–51 | EvtVnd4 | bitfield32 | — | Vendor events 4 |

Model 121 — Inverter Settings

Method: readInverterSettings()

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 22 | WMax_SF | int16 | Power SF | | 23 | VRef_SF | int16 | Voltage reference SF | | 24 | VRefOfs_SF | int16 | Voltage offset SF | | 25 | VMinMax_SF | int16 | Min/max voltage SF | | 26 | VAMax_SF | int16 | Apparent power SF | | 27 | VArMax_SF | int16 | Reactive power SF | | 28 | WGra_SF | int16 | Ramp rate SF | | 29 | PFMin_SF | int16 | Power factor SF | | 30 | MaxRmpRte_SF | int16 | Max ramp rate SF | | 31 | ECPNomHz_SF | int16 | Frequency SF |

Data Registers

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 2 | WMax | uint16 | WMax_SF | Maximum power output (W) | | 3 | VRef | uint16 | VRef_SF | Voltage at PCC (V) | | 4 | VRefOfs | int16 | VRefOfs_SF | Voltage offset from PCC (V) | | 5 | VMax | uint16 | VMinMax_SF | Maximum voltage (V) | | 6 | VMin | uint16 | VMinMax_SF | Minimum voltage (V) | | 7 | VAMax | uint16 | VAMax_SF | Maximum apparent power (VA) | | 8 | VArMaxQ1 | int16 | VArMax_SF | Max reactive power Q1 (VAr) | | 9 | VArMaxQ2 | int16 | VArMax_SF | Max reactive power Q2 (VAr) | | 10 | VArMaxQ3 | int16 | VArMax_SF | Max reactive power Q3 (VAr) | | 11 | VArMaxQ4 | int16 | VArMax_SF | Max reactive power Q4 (VAr) | | 12 | WGra | uint16 | WGra_SF | Default ramp rate (%WMax/sec) | | 13 | PFMinQ1 | int16 | PFMin_SF | Min power factor Q1 | | 14 | PFMinQ2 | int16 | PFMin_SF | Min power factor Q2 | | 15 | PFMinQ3 | int16 | PFMin_SF | Min power factor Q3 | | 16 | PFMinQ4 | int16 | PFMin_SF | Min power factor Q4 | | 17 | VArAct | enum16 | — | VAR action on mode change | | 18 | ClcTotVA | enum16 | — | Total VA calculation method | | 19 | MaxRmpRte | uint16 | MaxRmpRte_SF | Maximum ramp rate (%WGra) | | 20 | ECPNomHz | uint16 | ECPNomHz_SF | Nominal frequency (Hz) | | 21 | ConnPh | enum16 | — | Connected phase (single phase) |

Model 123 — Inverter Controls

Method: readInverterControls() / writeInverterControls()

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 21 | WMaxLimPct_SF | int16 | Power limit SF | | 22 | OutPFSet_SF | int16 | Power factor SF | | 23 | VArPct_SF | int16 | VAR percentage SF |

Connection Control

| Offset | Field | Type | R/W | Description | |--------|-------|------|-----|-------------| | 0 | Conn_WinTms | uint16 | R | Time window for connect/disconnect (sec) | | 1 | Conn_RvrtTms | uint16 | R | Timeout for connect/disconnect (sec) | | 2 | Conn | enum16 | W | Connect/disconnect (0=DISCONNECT, 1=CONNECT) |

Power Limit Control

| Offset | Field | Type | R/W | SF | Description | |--------|-------|------|-----|----|-------------| | 3 | WMaxLimPct | uint16 | W | WMaxLimPct_SF | Power limit (%WMax) | | 4 | WMaxLimPct_WinTms | uint16 | R | — | Time window (sec) | | 5 | WMaxLimPct_RvrtTms | uint16 | R | — | Timeout (sec) | | 6 | WMaxLimPct_RmpTms | uint16 | R | — | Ramp time (sec) | | 7 | WMaxLim_Ena | enum16 | W | — | Enable (0=DISABLED, 1=ENABLED) |

Power Factor Control

| Offset | Field | Type | R/W | SF | Description | |--------|-------|------|-----|----|-------------| | 8 | OutPFSet | int16 | W | OutPFSet_SF | Power factor setpoint | | 9 | OutPFSet_WinTms | uint16 | R | — | Time window (sec) | | 10 | OutPFSet_RvrtTms | uint16 | R | — | Timeout (sec) | | 11 | OutPFSet_RmpTms | uint16 | R | — | Ramp time (sec) | | 12 | OutPFSet_Ena | enum16 | W | — | Enable (0=DISABLED, 1=ENABLED) |

Reactive Power Control

| Offset | Field | Type | R/W | SF | Description | |--------|-------|------|-----|----|-------------| | 13 | VArWMaxPct | int16 | R | VArPct_SF | Reactive power at max W (%) | | 14 | VArMaxPct | int16 | R | VArPct_SF | Max reactive power (%) | | 15 | VArAvalPct | int16 | R | VArPct_SF | Available reactive power (%) | | 16 | VArPct_WinTms | uint16 | R | — | Time window (sec) | | 17 | VArPct_RvrtTms | uint16 | R | — | Timeout (sec) | | 18 | VArPct_RmpTms | uint16 | R | — | Ramp time (sec) | | 19 | VArPct_Mod | enum16 | R | — | Mode (0=NONE, 1=WMAX, 2=VARMAX) | | 20 | VArPct_Ena | enum16 | R | — | Enable (0=DISABLED, 1=ENABLED) |

Model 124 — Battery Basic Storage Controls

Method: readBatteryData() / writeBatteryControls()

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 18 | WChaMax_SF | int16 | Max charge power SF | | 19 | WChaDisChaGra_SF | int16 | Charge/discharge gradient SF | | 20 | VAChaMax_SF | int16 | Max charging VA SF | | 21 | MinRsvPct_SF | int16 | Min reserve percentage SF | | 22 | ChaState_SF | int16 | Charge state SF | | 23 | StorAval_SF | int16 | Available storage SF | | 24 | InBatV_SF | int16 | Battery voltage SF | | 25 | InOutWRte_SF | int16 | Charge/discharge rate SF |

Data Registers

| Offset | Field | Type | R/W | SF | Description | |--------|-------|------|-----|----|-------------| | 2 | WChaMax | uint16 | W | WChaMax_SF | Max charge power (W) | | 3 | WChaGra | uint16 | R | WChaDisChaGra_SF | Charge rate gradient (%/sec) | | 4 | WDisChaGra | uint16 | R | WChaDisChaGra_SF | Discharge rate gradient (%/sec) | | 5 | StorCtlMod | bitfield16 | W | — | Storage control mode (see enum) | | 6 | VAChaMax | uint16 | R | VAChaMax_SF | Max charging VA | | 7 | MinRsvPct | uint16 | W | MinRsvPct_SF | Min reserve (%) | | 8 | ChaState | uint16 | R | ChaState_SF | State of charge (%AhrRtg) | | 9 | StorAval | uint16 | R | StorAval_SF | Available storage (AH) | | 10 | InBatV | uint16 | R | InBatV_SF | Battery voltage (V) | | 11 | ChaSt | enum16 | R | — | Charge status (see enum) | | 12 | OutWRte | int16 | W | InOutWRte_SF | Discharge rate (%WDisChaMax) | | 13 | InWRte | int16 | W | InOutWRte_SF | Charge rate (%WChaMax) | | 14 | InOutWRteWinTms | uint16 | R | — | Rate change time window (sec) | | 15 | InOutWRteRvrtTms | uint16 | R | — | Rate change timeout (sec) | | 16 | InOutWRteRmpTms | uint16 | R | — | Rate change ramp time (sec) | | 17 | ChaGriSet | enum16 | W | — | Charge source (0=PV, 1=GRID) |

Model 160 — MPPT (Multiple Maximum Power Point Tracker)

Method: readAllMPPTData() / readMPPTData(moduleId)

Fixed Block (Scale Factors)

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 2 | DCA_SF | int16 | DC current SF | | 3 | DCV_SF | int16 | DC voltage SF | | 4 | DCW_SF | int16 | DC power SF | | 5 | DCWH_SF | int16 | DC energy SF | | 8 | N | uint16 | Number of MPPT modules |

Repeating Module Block (20 registers each)

Module 1 starts at offset 10, Module 2 at offset 30, Module N at offset 10 + (N-1) × 20.

| Relative Offset | Field | Type | SF | Description | |-----------------|-------|------|----|-------------| | 0 | ID | uint16 | — | Module ID | | 1–8 | IDStr | string (8 regs) | — | Module string identifier | | 9 | DCA | uint16 | DCA_SF | DC current (A) | | 10 | DCV | uint16 | DCV_SF | DC voltage (V) | | 11 | DCW | uint16 | DCW_SF | DC power (W) | | 12–13 | DCWH | acc32 | DCWH_SF | Cumulative DC energy (Wh) | | 14–15 | Tms | uint32 | — | Timestamp (seconds since epoch) | | 16 | Tmp | int16 | fixed (−1) | Module temperature (°C) | | 17 | DCSt | enum16 | — | Operating state |

Models 201/203/204 — Meters

Method: readMeterData()

The SDK reads Model 203 (3-Phase Delta), 204 (3-Phase Wye), or 201 (Single-Phase) — trying in that order. All three share the same register offsets for the fields we read:

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 17 | Hz_SF | int16 | Frequency SF | | 22 | W_SF | int16 | Power SF | | 54 | TotWh_SF | int16 | Energy SF |

Data Registers

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 16 | Hz | uint16 | Hz_SF | Frequency (Hz) | | 18 | W | int16 | W_SF | Total real power (W) | | 38–39 | TotWhExp | acc32 | TotWh_SF | Total exported energy (Wh) | | 46–47 | TotWhImp | acc32 | TotWh_SF | Total imported energy (Wh) |

Model 802 — Battery Base

Method: readBatteryBaseData()

Scale Factors

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 52 | AHRtg_SF | int16 | Amp-hour rating SF | | 53 | WHRtg_SF | int16 | Watt-hour rating SF | | 54 | WChaDisChaMax_SF | int16 | Charge/discharge max rate SF | | 55 | DisChaRte_SF | int16 | Self-discharge rate SF | | 56 | SoC_SF | int16 | State of charge SF | | 57 | DoD_SF | int16 | Depth of discharge SF | | 58 | SoH_SF | int16 | State of health SF | | 59 | V_SF | int16 | Voltage SF | | 60 | CellV_SF | int16 | Cell voltage SF | | 61 | A_SF | int16 | Current SF | | 62 | AMax_SF | int16 | Max current SF | | 63 | W_SF | int16 | Power SF |

Nameplate (Offsets 2–5)

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 2 | AHRtg | uint16 | AHRtg_SF | Nameplate charge capacity (AH) | | 3 | WHRtg | uint16 | WHRtg_SF | Nameplate energy capacity (WH) | | 4 | WChaRteMax | uint16 | WChaDisChaMax_SF | Max charge rate (W) | | 5 | WDisChaRteMax | uint16 | WChaDisChaMax_SF | Max discharge rate (W) |

State of Charge / Health (Offsets 6–13)

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 6 | DisChaRte | uint16 | DisChaRte_SF | Self-discharge rate (%) | | 7 | SoCMax | uint16 | SoC_SF | Max state of charge (%) | | 8 | SoCMin | uint16 | SoC_SF | Min state of charge (%) | | 9 | SoCRsvMax | uint16 | SoC_SF | Max reserve SOC (%) | | 10 | SoCRsvMin | uint16 | SoC_SF | Min reserve SOC (%) | | 11 | SoC | uint16 | SoC_SF | Current state of charge (%) | | 12 | DoD | uint16 | DoD_SF | Depth of discharge (%) | | 13 | SoH | uint16 | SoH_SF | State of health (%) |

Status (Offsets 14–22)

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 14–15 | NCyc | uint32 | Cycle count | | 16 | ChaSt | enum16 | Charge status (see enum) | | 17 | LocRemCtl | enum16 | Local/remote control mode | | 21 | Typ | enum16 | Battery type (see enum) | | 22 | State | enum16 | Battery bank state (see enum) |

Events (Offsets 26–33)

| Offset | Field | Type | Description | |--------|-------|------|-------------| | 26–27 | Evt1 | bitfield32 | Event bitfield 1 | | 28–29 | Evt2 | bitfield32 | Event bitfield 2 | | 30–31 | EvtVnd1 | bitfield32 | Vendor event bitfield 1 | | 32–33 | EvtVnd2 | bitfield32 | Vendor event bitfield 2 |

Voltage (Offsets 34–43)

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 34 | V | uint16 | V_SF | Battery voltage (V) | | 35 | VMax | uint16 | V_SF | Max battery voltage (V) | | 36 | VMin | uint16 | V_SF | Min battery voltage (V) | | 37 | CellVMax | uint16 | CellV_SF | Max cell voltage (V) | | 38 | CellVMaxStr | uint16 | — | String containing max cell | | 39 | CellVMaxMod | uint16 | — | Module containing max cell | | 40 | CellVMin | uint16 | CellV_SF | Min cell voltage (V) | | 41 | CellVMinStr | uint16 | — | String containing min cell | | 42 | CellVMinMod | uint16 | — | Module containing min cell | | 43 | CellVAvg | uint16 | CellV_SF | Average cell voltage (V) |

Current (Offsets 44–46)

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 44 | A | int16 | A_SF | Battery current (A) | | 45 | AChaMax | uint16 | AMax_SF | Max charge current (A) | | 46 | ADisChaMax | uint16 | AMax_SF | Max discharge current (A) |

Power / Control (Offsets 47–51)

| Offset | Field | Type | SF | Description | |--------|-------|------|----|-------------| | 47 | W | int16 | W_SF | Battery power (W, +charge/−discharge) | | 48 | ReqInvState | enum16 | — | Requested inverter state | | 49 | ReqW | int16 | W_SF | Requested power (W) | | 50 | SetOp | enum16 | — | Set operation | | 51 | SetInvState | enum16 | — | Set inverter state |

Writable Registers

Model 123 — Inverter Controls (writeInverterControls)

| Register Offset | Field | Scale Factor Offset | Description | |----------------|-------|---------------------|-------------| | 2 | Conn | — | Connect/disconnect | | 3 | WMaxLimPct | 21 (WMaxLimPct_SF) | Power limit percentage | | 7 | WMaxLim_Ena | — | Throttle enable/disable | | 8 | OutPFSet | 22 (OutPFSet_SF) | Power factor setpoint | | 12 | OutPFSet_Ena | — | PF control enable/disable |

Model 124 — Battery Controls (writeBatteryControls)

| Register Offset | Field | Scale Factor Offset | Description | |----------------|-------|---------------------|-------------| | 2 | WChaMax | 18 (WChaMax_SF) | Max charge power (W) | | 5 | StorCtlMod | — | Storage control mode bits | | 7 | MinRsvPct | 21 (MinRsvPct_SF) | Min reserve percentage | | 12 | OutWRte | 25 (InOutWRte_SF) | Discharge rate (%) | | 13 | InWRte | 25 (InOutWRte_SF) | Charge rate (%) | | 17 | ChaGriSet | — | Charge source (PV/Grid) |

Helper: setFeedInLimit(limitW)

Reads WMax from Model 121, computes (limitW / WMax) × 100, then writes WMaxLimPct + enables WMaxLim_Ena via Model 123. Pass null to disable the limit.

Helper: setStorageMode(mode) / enableGridCharging(enable)

Convenience wrappers around writeBatteryControls() for common battery operations.

Enum Reference

SunspecBatteryChargeState (Model 124 offset 11 / Model 802 offset 16)

| Value | Name | Description | |-------|------|-------------| | 1 | OFF | Battery off | | 2 | EMPTY | Battery empty | | 3 | DISCHARGING | Discharging | | 4 | CHARGING | Charging | | 5 | FULL | Fully charged | | 6 | HOLDING | Holding charge | | 7 | TESTING | Under test |

SunspecStorageControlMode (Model 124 offset 5 — bitfield)

| Bit | Value | Name | Description | |-----|-------|------|-------------| | 0 | 0x0001 | CHARGE | Enable charging | | 1 | 0x0002 | DISCHARGE | Enable discharging |

Derived modes via setStorageMode():

| Mode | Bits | Description | |------|------|-------------| | CHARGE | 0x01 | Charge only | | DISCHARGE | 0x02 | Discharge only | | HOLDING | 0x00 | Neither charge nor discharge | | AUTO | 0x03 | Both charge and discharge |

SunspecChargeSource (Model 124 offset 17)

| Value | Name | Description | |-------|------|-------------| | 0 | PV | Charge from PV only | | 1 | GRID | Charge from grid |

SunspecEnableControl (Model 123 — various enable fields)

| Value | Name | |-------|------| | 0 | DISABLED | | 1 | ENABLED |

SunspecBatteryType (Model 802 offset 21)

| Value | Name | |-------|------| | 0 | NOT_APPLICABLE_UNKNOWN | | 1 | LEAD_ACID | | 2 | NICKEL_METAL_HYDRIDE | | 3 | NICKEL_CADMIUM | | 4 | LITHIUM_ION | | 5 | CARBON_ZINC | | 6 | ZINC_CHLORIDE | | 7 | ALKALINE | | 8 | RECHARGEABLE_ALKALINE | | 9 | SODIUM_SULFUR | | 10 | FLOW | | 11 | SUPER_CAPACITOR | | 99 | OTHER |

SunspecBatteryBankState (Model 802 offset 22)

| Value | Name | |-------|------| | 1 | DISCONNECTED | | 2 | INITIALIZING | | 3 | CONNECTED | | 4 | STANDBY | | 5 | SOC_PROTECTION | | 6 | SUSPENDING | | 99 | FAULT |