The Solis S1-W4G-ST (With SIM, USB) (SOL-S1-W4G-ST-S6-USB-S) is a Wi-Fi + 4G cellular data logging stick for Solis S6 series inverters, supplied with a pre-installed Nano SIM card valid for 5 years. It connects to SolisCloud primarily via 2.4 GHz Wi-Fi, automatically switching to 4G cellular as fallback if Wi-Fi becomes unavailable — with no manual action required. Because the SIM is pre-installed and pre-activated, 4G monitoring works straight from the box: plug the logger into the inverter, configure Wi-Fi if available, and the system is monitored over either connection immediately. Data uploads every 5 minutes to the SolisCloud app (iOS and Android). Up to 10 inverters via RS485. Bluetooth for local configuration and one-key RS485 address assignment. Three LEDs: NET, COM, PWR. IP65. Dimensions: 128 × 50 × 34 mm, 79 g. 2-year warranty.
Wi-Fi+4G
Dual Path
5-yr SIM
Included
Auto
4G Failover
10 inv.
Per Logger
IP65
Protection
2-Year
Warranty
ℹ USB connector — Solis S6 series only: This logger uses a USB-type connector and is designed for Solis S6 series inverters which have a USB-type COM port. For earlier Solis models with a 4-pin COM port (4G, 5G, S5 series), the S1-W4G-ST (4-Pin) version is required. Check the Solis Datalogger Compatibility Guide at solis-service.solisinverters.com.
✅ 5-year SIM pre-installed — 4G ready straight from the box: The SIM card is already installed and activated. No SIM sourcing, no activation steps, no APN configuration required. The 5-year plan covers the operational lifetime of a typical residential installation. After 5 years, a replacement SIM (any standard Nano SIM on a UK 4G data plan) can be inserted into the same slot.
With SIM vs No SIM — Which Version Do You Need?
✅ This product — SOL-S1-W4G-ST-S6-USB-S (With SIM)
Pre-installed Nano SIM with 5-year data plan included. Insert and go — 4G works straight from the box. No SIM sourcing, no activation. Best for: straightforward installations, rapid commissioning, or any site where organising a SIM separately adds friction.
SOL-S1-W4G-ST-S6-USB (No SIM)
Empty Nano SIM slot — insert your own SIM. Best for: installers who have existing IoT SIM contracts, prefer a specific network, or want longer/custom plan terms. Identical hardware, lower upfront cost.
Key Features
5-Year SIM Pre-Installed — 4G Active Straight from the Box
The included Nano SIM has a 5-year data plan pre-loaded. Unlike the No-SIM version, there is nothing to organise before commissioning: plug the logger into the S6 inverter, power on, and 4G connectivity is available immediately as either the primary path (where Wi-Fi is absent) or the automatic failover (where Wi-Fi is present but may fail). The 5-year term aligns with typical inverter warranty periods and means no mid-installation monitoring gaps from an expired SIM.
5-year SIM includedPre-activatedNano SIM formatReady to go
The logger connects to SolisCloud primarily via 2.4 GHz Wi-Fi when a suitable network is available. If the Wi-Fi connection fails — broadband outage, router issue, ISP maintenance — the logger automatically switches to 4G cellular, continuing to upload data to SolisCloud at the standard 5-minute interval. When Wi-Fi is restored, it switches back silently. This dual-path architecture means monitoring history has no gaps from network interruptions, even in locations with unreliable broadband.
On sites with no broadband connection at all — remote rural properties, commercial rooftop systems on unoccupied buildings, agricultural installations, or any location where running broadband to the inverter location is impractical — this logger can operate entirely on 4G cellular. The pre-installed SIM means there is no dependency on the property’s internet infrastructure whatsoever. Data usage is minimal at 5-minute polling intervals: a low-data IoT plan is more than sufficient.
No broadband needed4G standaloneRemote sites
USB Connector — Insert+Lock into Solis S6 COM Port
The touch-safe USB Insert+Lock connector plugs directly into the USB-type COM port on Solis S6 series inverters. No adapters, tools or additional cabling required. Power is drawn from the inverter via the COM port.
USB Insert+LockS6 onlyTouch-safe
One-Key RS485 Address Assignment — Fast Multi-Inverter Commissioning
Trigger via the SolisCloud app over Bluetooth: the logger automatically scans the RS485 bus and assigns sequential addresses to all connected inverters. Up to 10 Solis inverters can be monitored through a single logger via RS485 daisy-chain. Eliminates manual address entry on each inverter display during commissioning.
One-key assignmentUp to 10 invertersRS485 daisy-chain
Bluetooth — Local Wi-Fi Configuration, No AP Mode
Wi-Fi SSID and password are entered via Bluetooth in the SolisCloud app. No AP mode setup: the phone does not need to disconnect from its own Wi-Fi. Bluetooth also enables local firmware updates and device status checks.
Bluetooth setupNo AP modeOTA firmware
Three LEDs — NET, COM, PWR — Instant Status
NET: server/network connection (Wi-Fi or 4G). COM: RS485 inverter communication. PWR: power/hardware. Solid = ok; flashing = connecting; off = fault. On-site diagnosis at a glance without the app.
NETCOMPWR
IP65, −30°C to +65°C, 79 g
Dust-tight and water-jet resistant. Operating range −30°C to +65°C, 5 – 95% RH. Compact at 128 × 50 × 34 mm, 79 g. Suitable for all outdoor and indoor inverter locations.
IP65−30°C to +65°C79g
Technical Specifications
Communication
Wi-Fi Standard
802.11b/g/n — 2.4 GHz only (not 5 GHz)
Cellular
4G LTE / GSM/GPRS: 850/900/1800/1900 MHz
SIM Card
Nano SIM — pre-installed, 5-year plan included
Bluetooth
Yes — local configuration and debugging
Inverter Communication
RS485 (Modbus RTU)
Connection Failover
Auto Wi-Fi → 4G if Wi-Fi unavailable; auto-restores on Wi-Fi return
Data
Upload Interval
5 minutes
Platform
SolisCloud
App
SolisCloud (iOS and Android)
Multi-Inverter
Max Inverters per Logger
10 (RS485 daisy-chain)
One-Key Address Assignment
Yes — via SolisCloud app over Bluetooth
Configuration
Wi-Fi Setup
Bluetooth via SolisCloud app / AP mode (browser)
Power
Operating Voltage
DC 5V (±5%)
Power Consumption
≤5 W
Physical
Connector
USB — Insert+Lock
Dimensions (L×W×H)
128 × 50 × 34 mm
Weight
79 g
Indicators
3 × LED: NET, COM, PWR
Buttons
1 × RESET (short = data push; long = factory reset)
Environment
Protection
IP65
Operating Temperature
−30°C to +65°C
Operating Humidity
5 – 95% RH (non-condensing)
Storage Temperature
−40°C to +70°C
Storage Humidity
<40%
Max Altitude
4,000 m
Compatibility
Compatible Inverters
Solis S6 series (USB-type COM port)
Not Compatible
Solis 4G, 5G, S5 series — use S1-W4G-ST (4-Pin) instead
Warranty and Certification
Warranty
2 years
Certifications
CE, FCC
Manufacturer
Ginlong Technologies Co., Ltd (Solis)
Frequently Asked Questions
What is the difference between this (With SIM) and the No-SIM USB version?
The hardware is identical — same connector, same Wi-Fi, same 4G, same specs and same failover behaviour. The only difference is the SIM card: this version has a pre-installed Nano SIM with a 5-year data plan already activated. The No-SIM version (SOL-S1-W4G-ST-S6-USB) ships with an empty SIM slot and requires you to source and insert your own Nano SIM. Choose the With SIM version for simpler commissioning and no SIM management. Choose the No-SIM version if you have an existing IoT SIM contract or want to choose your own network and plan terms.
Does 4G work on all UK networks?
The included SIM is a multi-network SIM designed for IoT monitoring use. It roams across available UK 4G networks and selects the strongest signal. Coverage depends on local 4G infrastructure. In areas with weak or no 4G coverage, the logger will use Wi-Fi as the sole connection. If cellular connectivity is critical for a remote site, check 4G coverage at the installation postcode before ordering.
What happens when the 5-year SIM plan expires?
After 5 years, the pre-installed SIM will expire. At that point, you can insert any standard Nano SIM on a UK 4G-enabled data plan into the SIM slot. Data usage is very low (small packets at 5-minute intervals), so a basic pay-as-you-go or IoT SIM with a modest data allowance is sufficient. The logger will continue working on Wi-Fi during any gap between the old SIM expiring and a new one being inserted.
Which Solis inverters are compatible?
This logger is compatible with Solis S6 series inverters, which have a USB-type COM port. Solis 4G, 5G and S5 series inverters use a 4-pin COM port and require the S1-W4G-ST (4-Pin) version. Check the Solis Datalogger Compatibility Guide at solis-service.solisinverters.com for a full model list.
Is broadband or Wi-Fi required at the site?
No. When Wi-Fi is unavailable, the logger operates entirely on 4G cellular using the included SIM. This makes it suitable for remote rural properties, commercial rooftop installations on unoccupied buildings, agricultural sites, and any location without reliable broadband. If Wi-Fi is present, the logger uses it as primary and falls back to 4G only if needed.
Related Products
Solis S1-W4G-ST (No SIM, USB)
Same logger — empty SIM slot, bring your own Nano SIM
Solis S2-WL-ST (USB)
Wi-Fi + LAN (no cellular) for S6 inverters — with Modbus TCP
Solis S5 Wi-Fi Data Logger (4-Pin)
Dual-band 2.4/5 GHz Wi-Fi for Solis 4G/5G/S5 series
Solis S1-W4G-ST (4-Pin, With SIM)
Same logger in 4-pin format for Solis 4G/5G/S5 inverters
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
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