If you own a Victron energy system, you’ve likely experienced the “problem” of a sunny afternoon: your batteries are 100% charged, your house is cool, and your solar panels are sitting idle because there is nowhere for that free energy to go.
With the recent release of Venus OS v3.70, Victron has introduced native integration for Shelly smart devices. This is a game-changer for UK homeowners looking to turn that “wasted” solar into hot water, a warm home, or a ready-to-use jacuzzi.
Previously, linking Victron to Shelly required complex coding and custom scripts. Now, it is plug-and-play. Your Victron GX device (such as the Cerbo GX or Ekrano GX) can now “talk” directly to Shelly relays over your home Wi-Fi. Once connected, your Shelly switches appear directly on your Victron touchscreens and the VRM app, allowing you to control heavy appliances alongside your battery stats.
The smartest way to use this integration is for Opportunity Loading. Instead of letting solar production “curtail” (stop) when batteries are full, you “dump” that excess power into high-energy appliances that act as thermal batteries.
By fitting a Shelly Plus 1PM to your immersion heater or underfloor heating manifold, you can program your system to wait until your house batteries reach 95% charge. You can then trigger the heating only when there is at least 2kW of excess solar, storing that energy as heat in your water tank or floor slab for later that evening.
Jacuzzis and saunas are notorious “energy hogs.” Using a Shelly Pro relay, you can ensure these only run when the sun is shining. This ensures your leisure time doesn’t lead to a massive electricity bill or accidentally drain your batteries mid-cycle.
Using the built-in Node-RED feature on the Victron “Large” firmware, you can even set a “pecking order”. You might choose to charge the house batteries first, heat the domestic hot water second, and then turn on the jacuzzi heater only if there is still a surplus.
Everything happens locally on your home network. It’s fast, secure, and works even if your internet goes down. You can still manually override and turn on your sauna from your phone via the Victron VRM app while you’re on your way home from work.
Shelly devices are affordable and easy to install on standard UK DIN-rail consumer units or behind existing wall switches. The system can also be set to instantly “shed” these heavy loads when a cloud passes overhead or when someone turns on a kettle, protecting your battery from strain.
To take advantage of this, ensure your Victron GX device is updated to v3.70 or later. You can find the new options under Settings -> Integrations in your Device List.
For high-current appliances such as saunas or large hot tubs, we recommend using the Shelly relay to drive a heavy-duty contactor. This ensures the system remains reliable for years to come.