Sunsynk Hybrid Inverter Setup — LCD Settings, Battery, System Mode & Grid
Complete walkthrough of the Sunsynk hybrid inverter LCD interface. Every setting explained in plain English — battery type, charge and discharge schedules, system mode, export limits, and UK grid compliance. Covers the Ecco and standard Sunsynk single-phase hybrids (3.6kW–8kW).
We configure Sunsynk systems remotely via SolarMan — battery schedules, export limits, Octopus tariff windows, and grid compliance settings. Most systems done in one session.
Book Remote Configuration — from £75 → Sunsynk hubThis guide covers LCD interface settings only — not physical installation or wiring.
Accessing the Settings menu
From the Home Page, tap the gear icon in the top-right corner of the LCD screen. This opens the System Setup screen with eight icons: Basic, Battery, Grid, System Mode, Advance, Aux Load, Fault Codes, and Li BMS. Each section is covered below in the order you'll typically configure them.
Physical buttons
The LCD has four physical buttons below the screen: Esc (go back), Up (increase value), Down (decrease value), and Enter (confirm). You must press Enter after changing any setting — if you don't, the change won't be saved. On touchscreen models, you can tap directly on settings to change them.
LED indicators
Four LEDs sit above the screen: DC (green = PV connected), AC (green = grid connected), Normal (green = running normally), and Alarm (red = fault active). If Alarm is red, check Fault Codes before changing any settings.
Basic Setup — time, display, and reset
Tap the Basic icon on the Settings screen. This section has four tabs: Time, Display, Reset, and Remote.
Time
Set the correct date, time, and AM/PM. This is critical for charge and discharge schedules — if the clock is wrong by even an hour, your cheap-rate charging window won't fire when expected. During BST (late March–late October), make sure the clock reflects the +1 hour offset.
Display
Set your system name (appears on the Home Page), toggle the beeper on or off, and configure Auto Dim (how many seconds before the LCD backlight dims). The beeper sounds for low battery warnings and fault alerts — most homeowners prefer it on.
Reset and Lock
Factory Reset restores all settings to defaults (password: 9999). Lock Out All Changes prevents any setting changes until unlocked (password: 7777). System Selfcheck runs an internal diagnostic (password: 1234). Locked Inverter fully locks the unit — only Sunsynk technical support can unlock it.
Remote
Tick "Allow remote control" to enable settings changes via SolarMan. This should be enabled for remote diagnostic and configuration support. If disabled, only LCD changes are possible.
Battery settings — type, capacity, and charging
Tap the Battery icon on the Settings screen. Three tabs: Batt Type, Batt Charge, and Shut Down.
Battery Type (Batt Type tab)
Select your battery chemistry. Most UK installations use lithium-ion batteries.
After selecting battery type, configure:
Battery Charging (Batt Charge tab)
This tab controls how and when the battery charges from the grid or generator.
For lithium batteries, voltage settings (Float V, Absorption V, Equalization V) are managed automatically by the BMS. For lead-acid batteries, use the manufacturer's recommended values — typical AGM: Float 55.2V, Absorption 57.6V, Equalization 58.8V for a 48V bank.
Shutdown and Low Battery (Shut Down tab)
These settings control how deeply the battery discharges before the inverter takes action. Getting these right protects battery health and prevents nuisance shutdowns.
System Mode — export, load priority, and schedules
Tap the System Mode icon. This is the most important settings page — it controls how your system behaves day to day. Two tabs: System 1 (mode selection) and System 2 (charge/discharge scheduling).
System 1 — operating mode
Six settings control the core behaviour of your system:
When ticked, the CT coil monitors grid export and the inverter reduces output to prevent any power flowing back to the grid. Use this if you do not have an export tariff. The system will power your home load and charge the battery, but never export.
When ticked, the inverter operates in eco mode: solar covers your home load first, then charges the battery, then exports any surplus to the grid. This is the correct setting for SEG, Octopus Flux, or Octopus Agile export tariffs. When unticked, the inverter covers load, charges the battery, and then throttles PV production at 100% SOC — no export happens.
When ticked, the inverter only powers the backup (essential) load connected to the inverter's load port. The home load on the grid side receives no inverter power. Rarely used in standard UK setups — mainly for off-grid or specific backup configurations.
The amount of power (in watts) the inverter always draws from the grid. Set to 0W for standard UK credit meters. Only increase this (20–100W) for prepayment meters where Reverse Power Detection can cause the meter to trip. Almost never needed in the UK.
Caps the maximum combined output to both Load and Grid ports. This is not your export limit (that's Max Sell Power). The default matches your inverter rating (e.g., 5000W for a 5kW model). Only reduce this if instructed by an engineer — it gets set to Low automatically if an over-current fault occurs.
When ticked, solar generation is directed to your home load first, then to the battery. This is the standard UK setting — you want to self-consume as much solar as possible. When unticked, solar charges the battery first, which is rarely what you want unless running a specific arbitrage strategy.
System 2 — charge and discharge time windows
This is where you program when the battery charges from the grid and when it discharges. Tap the System 2 tab to see the scheduling grid.
Example: Octopus Go schedule
Cheap rate 00:30–04:30. Charge the battery to 100% overnight, then self-consume and discharge through the day.
| Slot | Start | End | Power | SOC | Grid |
|---|---|---|---|---|---|
| 1 | 00:30 | 04:30 | 5000 | 100% | Yes |
| 2 | 04:30 | 23:59 | 5000 | 20% | No |
Slot 1 charges from grid to 100%. Slot 2 discharges down to 20% (the Shutdown threshold) through the day. System 1 should have Zero Export ticked and Priority Load ticked.
Grid settings — UK compliance
Tap the Grid icon. These settings control how the inverter interacts with the UK grid. Grid settings are locked by default — tick "Unlock Grid Settings" and enter the password to make changes.
Lithium BMS settings
If you selected Lithium as battery type, tap the Li BMS icon to verify communication. The BMS page shows battery voltage, current, temperature, total SOC and SOH, and individual cell data.
Key settings when configuring lithium batteries:
Sunsynk setup questions
Zero Export prevents the inverter from sending power back to the grid. The CT coil detects any reverse power flow and the inverter reduces output to match your home load exactly. This is the correct setting for most UK installations unless you have an export tariff like Octopus Flux or SEG.
For standard UK credit meters, set Grid Trickle Feed to 0W. This setting only needs adjusting for prepayment meters where Reverse Power Detection can cause tripping — in that case, set it to 20–100W. Almost all UK homes should leave this at 0W.
Go to System Mode, tap System 2, tick User Timer, then set your cheap-rate window (e.g., Octopus Go: 00:30–04:30). Set Power to your inverter's maximum, SOC to 100%, and tick the Grid checkbox. On System 1, tick Zero Export and Priority Load. Time slots cannot cross midnight — split overnight windows into two slots if needed.
Shutdown is the battery reserve SOC — the inverter enters standby mode when the battery drops to this level. Low Batt is the warning threshold where the inverter beeps. Restart is the SOC level the battery must reach before the inverter resumes normal operation after a shutdown. Set Restart higher than Low Batt to prevent the system cycling on and off.
Enable Solar Export only if you are on an export tariff (SEG, Octopus Flux, Octopus Agile export). With it enabled, the inverter covers your home load first, charges the battery, then exports surplus. With it disabled, the inverter covers load, charges the battery, and then throttles PV at 100% SOC. Most tariff-optimised systems should enable Solar Export alongside the correct Max Sell Power (export limit).
Max Sell Power is your grid export limit in watts. For most UK domestic installations under G98, set this to 3600W (3.6kW). If your DNO has granted a G99 export allowance for a higher limit, set it accordingly. This prevents the inverter from exporting more than your connection agreement allows.
Need your Sunsynk configured correctly?
We configure Sunsynk hybrid inverters remotely via SolarMan — charge schedules, export limits, battery thresholds, and Octopus tariff windows. Most configurations completed in a single session.