Shelly + Victron: a comprehensive guide to relays, meters and contactors for making the most of surplus solar power

If you have a Victron system with Cerbo GX o Ekrano GX and when your battery is fully charged by mid-morning, you’re feeding energy back into the grid. With a Shelly Wi-Fi relay For less than €30, the GX itself can switch on the water heater, the pool pump or a heating element just when there’s excess sunlight, and switch them off when there’s no longer any excess. In this guide, we explain Which Shelly models are compatible with Victron?, which range to choose for each load, when a contactor is needed, and what mistakes to avoid.

Why Shelly and Victron get on so well

From Venus OS 3.60 onwards, the GX includes an official driver (dbus-shelly) which automatically detects any second-generation or later Shelly devices on the same network. Each Shelly can act as:

• Wi-Fi electricity meter (AC consumption, third-party PV inverter, generator or heat pump) visible in VRM.
• Wi-Fi switch controllable via the GX, VRM and Node-RED.
• Surplus actuator for GX Opportunity Loads, the feature (Venus OS 3.80, in beta as of September 2026) that automatically distributes surplus solar power amongst flexible loads.

For Opportunity Loads, there is one rule that changes everything: Shelly himself has to switch the load and measure its power. A Shelly Pro 3EM, which is simply a separate relay that switches a circuit, won’t work; a Shelly 1PM, which does both, will.

Shelly ranges: which one to choose for each load

1. Smart plugs (the quickest way to get started)

They plug in between the socket and the appliance. Ideal for small kettles, dehumidifiers, heaters or e-bike chargers.

• Shelly Plus Plug S (ref. SNPL-00112EU) — 12 A / 2.5 kW, Gen2, energy measurement. Officially tested by Victron.
• Shelly Plug S MTR Gen3 (ref. S3PL-00112EU) — 12 A, the successor to the previous model, with more accurate measurements and Bluetooth.
• Shelly Outdoor Plug S Gen3 (ref. S3PL-10112EU) — 16 A, IP54, for outdoor use (small swimming pool pump, watering).

2. Mini (for recessing into switch boxes)

The smallest on the market; they fit behind a switch. Be careful with the mains supply: 8 A maximum.

• Shelly 1PM Mini Gen3 (ref. S3SW-001P8EU) — 8 A / ~1.8 kW, with measurement. A favourite amongst the Victron community for its price (around €15).
• Shelly 1PM Mini Gen4 (ref. S4SW-001P8EU) — same as above, but with Zigbee and Matter added. Tested by Victron.
• Shelly PM Mini Gen3 (ref. S3PM-001PCEU16) — measurement only, 16 A, without relay. It is used as a meter, not as an actuator.
• Shelly 1 Mini Gen3/Gen4 — dry contact without a rating: can be used as a switch, no for Opportunity Loads.

3. Flush-mounted standard (16 A)

• Shelly 1PM Gen3 (ref. S3SW-001P16EU) and Shelly 1PM Gen4 (ref. S4SW-001P16EU) — 16 A / 3.5 kW with gauge. The right choice for a 1.5–2 kW water heater or a 2–3 kW heating element.
• Shelly 2PM Gen3 / Gen4 (ref. S3SW-002P16EU / S4SW-002P16EU) — two metered channels (10 A per channel, 16 A in total): two loads with a single device.
• Shelly Plus 1PM (ref. SNSW-001P16EU) and Plus 2PM — the previous generation (Gen2), which is fully compatible if you already have it.

4. Pro range (DIN rail, with Ethernet)

For the distribution board and for installers: 110–240 V power supply, LAN cable connection (much more reliable than Wi-Fi for the GX) and screw terminals.

• Shelly Pro 1pm (ref. SPSW-001PE16EU) — 1-channel 16 A with measurement. Officially tested by Victron.
• Shelly Pro 2PM (ref. SPSW-002PE16EU) — 2 channels, 16 A, with measurement (confirmed in the Opportunity Loads beta).
• Shelly Pro 4pm (ref. SPSW-004PE16EU) — 4 channels, 16 A (40 A in total) with metering and display. Tested by Victron. Ideal for managing four loads from the switchboard.
• Shelly Pro EM‑50 (ref. SPEM-002CEBEU50) — 2 x 50 A clamps + 1 x 2 A relay for the contactor coil. Tested by Victron. This is the key component for high-power loads (see below).
• Shelly Pro 3EM (ref. SPEM-003CEBEU) — three-phase meter with three 120 A clamps. Tested by Victron as a grid, PV inverter or consumption meter (also as three single-phase meters). It does not have a relay.
• Shelly Pro 3EM‑63 (direct measurement 63 A) and Pro 3EM‑400 (400 A clamps) — variants of the above for small or large connections.

5. Flush-mounted meters with a relay for a contactor

• Shelly EM Gen3 (ref. S3EM-002CXCEU) — 2 x 50 A clamps + 2 A relay. Successor to the first-generation Shelly EM (which no (it is compatible).
• Shelly 3EM‑63 Gen3 (ref. S3EM-003CXCEU63) — three-phase, direct measurement up to 63 A per phase.

Other devices compatible with Venus OS (though not for surplus stock)

Shelly Pro 1 (dry contact), Powerstrip Gen4 (4-socket power strip), Dimmer Gen3, Plus RGBW PM and Duo Gen3 bulbs appear as switches or dimmers in the GX. Useful for automating lighting via VRM, not for managing power surpluses.

Compatibility table: Shelly and Victron models

✅ = officially tested by Victron with the driver dbus-shelly. OL = Compatible as a GX Opportunity Loads actuator (switches and measures using the same device). All require Venus OS 3.60 or later.

* Pro EM‑50 and EM Gen3 have been tested with the driver (measurement + relay in a single unit); their use with a contactor within Opportunity Loads should be validated in the beta version before being taken for granted. Specifications are subject to review and may vary by region: check the code on the packaging.

What DOESN’T work

• The entire first generation (Gen1): Shelly 1, 1PM, 2.5, EM, 3EM, original Plug S. They use a different API and the current driver does not recognise them.
• Non-metric models as a means of managing surpluses: Shelly 1, Plus 1, Pro 1, Pro 2, Pro 3, 1 Mini. They can be used as manual switches, but Opportunity Loads ignores them.
• Combining a meter and a relay in separate devices (e.g. Pro 3EM + Pro 1): Victron requires that metering and switching be carried out on the same Shelly unit.
• DC loads: At present, Opportunity Loads only handles AC loads.

High-current loads: when and how to use a contactor

The built-in relays in the Shelly PM are designed to resistive loads of up to 16 A. Always use a contactor when the load is:

• A engine (swimming pool pump, well pump, compressor): the start-up surge damages the Shelly relay.
• A a power rating of more than 3 kW or any load that exceeds 80 % of the Shelly’s rated current on a continuous basis.
• Three-phase (air-source heat pumps, electric boilers, large pumps).

The right combination to keep Opportunity Loads running is a Shelly with a relay and clamp in the same unit (Shelly EM Gen3 or Shelly Pro EM‑50): the 2 A relay powers the contactor coil and the clamp measures the load’s actual power consumption. If you use a Shelly 1PM to energise the coil, the GX will only detect the coil’s power consumption (a few watts) and the algorithm will not know how much power is being supplied.

Which contactor to choose:

• DIN-rail modular system, 230 V AC coil, 2-pole for single-phase or 4-pole for three-phase.
• Calibre in Category AC-1 (resistive) 25 A for water heaters and heating elements up to 5 kW, 40 A for 6–9 kW. For motors, use the AC-3 category the manufacturer’s, which is more stringent.
• Common brands: Schneider iCT, Hager ESC, ABB ESB, Chint NCH8, Legrand CX³. Choose one quiet if the painting is in the flat.
• Add a thermal-magnetic designed for the load and, if the load is outdoors or in a damp area, a differential 30 mA.

Requirements and settings to enable the GX to recognise the Shelly

• GX-compatible: Cerbo GX, Ekrano GX, MultiPlus‑II GX or EasySolar‑II GX. Venus OS 3.60 or later to view them as a meter/switch; 3.80 (beta) for Opportunity Loads.
• Same local network Unlike the GX: discovery is via mDNS. No guest networks or client isolation on the router.
• 2.4 GHz Wi-Fi with good coverage; if the Shelly is within range, the Pro range via Ethernet prevents dropouts. If, on top of that, the GX doesn’t have good coverage, a GX LTE 4G modem terminates the connection to the VRM.
• Static IP or DHCP allocation For every Shelly: fewer surprises after a router reset.
• Updated Shelly firmware and Shelly’s cloud service can remain active: the GX communicates with the device locally, not via the cloud.
• In the GX: Settings → Integrations → Shelly, switch on the device and assign it the role (AC consumption, PV inverter, heat pump, generator, etc.). Next, under ‘Opportunity Loads’, add the load and define its priority and minimum power.
• For additional hard-wired relays without Shelly, Victron offers the GX IO-Extender 150 (currently being assessed by Victron for Opportunity Loads).
• Opportunity Loads and Dynamic ESS They cannot be used at the same time (for the time being).

Typical use cases and which Shelly to choose

Mistakes we often see

• Buy a First-generation Shelly EM “Because it’s cheap”: it doesn’t work with the current driver.
• Switch a swimming pool pump connected directly to a 1PM: the relay lasts for weeks.
• Place the Shelly in the guest network or on a repeater with NAT: the GX cannot detect it.
• Use a Shelly Pro 3EM as a network meter for ESS: it works, but the Wi-Fi causes a delay; for zero discharge with Victron, we prefer the VM‑3P75CT or the ET112/EM540 via RS485.
• To forget the neutral: All Shelly PM units are powered at 230 V and require L and N connections at the switchboard.

In summary

To get started with your Victron today: a Shelly 1PM Gen3 or a Plug S MTR Gen3 for the thermos, a Pro EM‑50 with contactor for the swimming pool or high-resistance training, and the range Pro via Ethernet if the installer fits it into a panel. Gen2 and above only; no Gen1. And if you’re unsure which model is suitable for your installation, please get in touch: at FV Componentes, we sell and configure Victron systems every day.

Sources: Victron Energy’s dbus-shelly driver documentation (GitHub), the official GX Opportunity Loads beta thread on the Victron Community, and Shelly’s technical data sheets. Part numbers may vary depending on the revision and region; always check the code on the packaging.