The Fox ESS 4G-2 Dongle is a 4G/GPRS cellular monitoring device that connects compatible Fox ESS inverters to the Fox ESS Cloud platform without requiring a home WiFi or wired network connection. It is the ideal solution for sites where no reliable broadband, WiFi, or GPRS signal is available, giving system owners and installers real-time performance data, historic generation records, and system alerts from anywhere via built-in cellular connectivity.
The 4G-2 variant is specifically engineered for H3 Pro inverters, which require an active polling communication approach to acquire data — a different method to standard Fox ESS 4G dongles, which is why two distinct 4G dongle types exist across the Fox ESS range.
4G / GPRS
Cellular Connection
USB Type A
Physical Interface
Typ. 1W
Power Consumption
5 Years
Connection Validity
Inverter Compatibility
This 4G-2 variant is built for H3 Pro inverters, which use an active polling method to retrieve data. It is not compatible with AC3, V series, or R series inverters. Confirm your exact inverter model and series before ordering, as Fox ESS produces more than one 4G dongle type depending on the inverter's communication method.
SIM Connection Validity
The embedded 4G connection is valid for 5 years from activation. After this period, a replacement dongle will be required to maintain remote monitoring — this is not a user-replaceable SIM card, so budget for renewal at the point of installation.
When to Choose Cellular Over WiFi
The 4G-2 is the right choice for installations with no reliable WiFi, LAN, or standard GPRS coverage at the inverter location, using the built-in cellular radio to maintain a monitoring connection independent of the property's own network.
Active Polling for H3 Pro Inverters
Purpose-built to use the active polling communication method required by H3 Pro inverters, ensuring reliable data acquisition where standard passive dongles are not compatible.
Built-In Cellular Connectivity
Connects via 4G/GPRS using a network operator SIM, giving remote monitoring coverage at sites with no fixed broadband or WiFi network available.
Outdoor-Rated IP65 Enclosure
Rated to IP65 for dust and water-jet ingress protection, and rated UL94V-0 for fire resistance, suiting direct outdoor installation alongside the inverter.
Wide Band Cellular Coverage
Supports an extensive range of FDD, TDD, and GSM frequency bands across EU and AU regional variants, maximising compatibility with local mobile network operators.
Plug-and-Play USB Installation
Connects via a standard USB Type A interface for straightforward installation, with RS485 communication at 9600bps (8/N/1) to the inverter.
Real-Time & Historic Monitoring
Streams live generation and consumption data to the Fox ESS Cloud app, while storing historic performance records and raising instant alerts if a fault occurs.
General
| Model |
Smart 4G (4G-2) |
| Product Type |
4G / GPRS Cellular Monitoring Dongle |
| Compatible Inverters |
Fox ESS H3 Pro (active polling variant) |
| Not Compatible With |
Fox ESS AC3, V series, R series |
| Connection Validity |
5 years from activation, then replacement required |
Electrical
| Input Voltage |
DC 7–12V |
| Power Consumption |
Typ. 1W |
Cellular & Communication
| Radio Frequency (EU) |
FDD: B1/B3/B5/B7/B8/B20 · TDD: B38/B40/B41 · GSM: B3/B8 |
| Radio Frequency (AU) |
FDD: B1/B2/B3/B4/B5/B7/B8/B28/B66 · TDD: B40 · GSM: B2/B3/B5/B8 |
| Antenna |
PCB antenna, internal |
| SIM |
Solid-mounted on PCB, internal |
| Connector |
USB Type A |
| Inverter Communication |
RS485, 9600bps 8/N/1 |
Physical & Environmental
| Dimensions (L×W×H) |
110 × 48 × 27mm |
| Weight |
50g |
| Operating Temperature |
-20°C to +60°C |
| Operating Humidity |
0–95%, no condensation |
| Maximum Altitude |
4000m |
| Ingress Protection |
IP65 |
| Fire Rating |
UL94V-0 |
| UV Immunity |
F1 |
Will the 4G-2 work with my Fox ESS AC3, V series or R series inverter?
No. The 4G-2 dongle is built specifically for H3 Pro inverters, which use an active polling communication method. It is not compatible with AC3, V series, or R series inverters — check your exact inverter model before ordering.
Why does Fox ESS make more than one 4G dongle?
H3 Pro inverters use a different, active polling approach to acquire data compared with other Fox ESS inverters. This requires a dedicated dongle design, which is why the 4G-2 exists alongside Fox ESS's standard 4G dongle.
Do I need to provide my own SIM card?
No. The SIM is solid-mounted internally on the dongle's PCB and is not user-replaceable. The cellular connection is valid for 5 years from activation, after which a new dongle is required.
Is the 4G-2 suitable for outdoor installation?
Yes. It carries an IP65 ingress protection rating, a UL94V-0 fire rating, and an operating temperature range of -20°C to +60°C, making it suitable for mounting outdoors alongside the inverter.
What happens after the 5-year connection period ends?
The embedded cellular connection is only valid for 5 years from activation. Once this period expires, the dongle will no longer maintain a data connection and a replacement unit will be needed to restore remote monitoring.
