🏠 Case Study: Building a Demo Home That Lives Off-Grid Without Oversizing

Why is this a Case Study, not just a Showcase?
This site was designed from the ground up to demonstrate that you don’t need a massive 8kW or 12kW inverter to live off-grid — not even in a full, modern household. With the right system design, smart automation, and energy discipline, even a 6kW inverter can deliver a 95% fully solar-powered lifestyle for a family of four.

System Overview and Goals

The home runs entirely on solar and batteries — with no grid connection active by default. Using Node-RED automation on a Victron GX, the system mimics a generator scenario:

• The grid is connected only when battery drops below 20%
• It disconnects again automatically when battery reaches 30%

This logic simulates a site where grid is treated as backup — just like a generator would be in a remote off-grid property.

Real-World Energy Performance

The house consumes around 500kWh/month — including:

• 2× 3kW geysers
• Electric oven and induction hob (no gas)
• Full scullery and standard appliances
• A 3-bedroom layout
• An electric lawnmower with a 5.5kW startup draw

Even with this load, during summer and good weather:

• A full battery at sunset typically still sits at 80% the next morning
• That’s 15 hours of use from just 20% of a 14kWh battery
• Winter is more challenging — in June, West Coast weather reduces PV dramatically, and grid support becomes necessary

Importantly, compared to competitor systems, this setup delivers notably better PV production under poor weather conditions — something we've seen firsthand.

Automation: Where Node-RED Takes Over

The true strength of this system is its automation layer — Node-RED running on the Cerbo GX, tightly integrated with Victron and Home Assistant.

1. Smart Grid Connection Logic
   Node-RED controls when the grid connects based on battery thresholds.
   Users can override this manually via:
   • The VRM portal (ESS menu toggle)
   • The Touch display
2. Overload Protection via Geyser Control
   If total load approaches or exceeds inverter limits (6kW rated, 7kW surge):
   • Node-RED will temporarily disable one or both geysers
   • This protects the inverter while keeping critical loads online
3. Thermal Storage via Secondary Geyser (Dump Load)
   A second geyser is configured in series as a dump load:
   • When the battery is full, this geyser heats using excess PV
   • At night, if the first geyser is emptied, it’s re-filled with hot water from the second one
   • This reduces or even eliminates the need for morning reheating, saving significant battery energy
4. Bonus Sensors for Demo & Display
   • A Ruuvi sensor in the kitchen displays ambient temperature
   • An EyeGas monitor shows gas bottle levels used for the braai
   • Both are visible in VRM and on the Touch 50 display, showing how easily non-energy devices can be integrated into the system

This approach combines battery storage, thermal storage, and practical automation into one cohesive system.

System Components

Victron Energy Platform:

• Inverter: MultiPlus II 6kW
• Battery: 1× 14.3kWh Solar MD lithium battery
• Solar: 4.6kWp PV array connected to the hybrid inverter
• Control: Cerbo GX with Touch 50

Automation & Monitoring:

• Node-RED running directly on GX for real-time control
• Cerbo GX controls Geyser 1 & 2 via Relay 1 & 2, which operate load-bearing contactors to switch the geysers
• Grid connection override available in VRM and local touchscreen
• Second geyser used for intelligent dump load and storage

Extended Automation (Home Assistant):

• Not shown here, but connected via MQTT
• Includes lights, motion sensors, CCTV, smart plugs, and energy meters
• Smart appliances like the tumble dryer are integrated via local automation
• (To be featured in a future dedicated automation showcase)

Conclusion

This house is proof that with smart design, modest hardware, and clever logic, a home can operate 95% solar-powered across a full 12-month cycle — using just a 6kW inverter.

It doesn’t just run — it runs smart.
👉 Contact us to learn how to maximize efficiency without oversizing your system

🌡️ Case Study: Smart Geyser Control with Victron + Node-RED

Why is this a Case Study, not just a Showcase?
This setup goes beyond simply monitoring or scheduling a geyser. It showcases how Node-RED running on Victron GX can fully replicate — and improve upon — the smart features of Geyserwise TUYA, while keeping all logic local, reliable, and deeply integrated with your Victron system.

The Challenge: Cloud Reliance in a Loadshedding Environment

The Geyserwise TUYA controller offers app-based smart scheduling and control. However, all timers and logic are cloud-hosted — and during loadshedding or internet dropouts, scheduled heating simply doesn’t happen.

While you can press the red override button manually, imagine the frustration: you’re heading out, need a hot shower, and discover the geyser never heated. Your options? Go to work cold, or go to work dirty.

The Solution: Full Geyser Automation via Node-RED

Using Node-RED on a Victron Cerbo GX, we rebuilt the TUYA logic locally — and then extended it. No internet needed. The system now provides:

• Local timers with full flexibility
• Force Heat button accessible via dashboard or VRM
• Adjustable temperature targets
• Mode switching: Off / Heat / Auto
• A Minimum Temperature safeguard — ensuring warm water always, even if it means using a bit of grid energy

This ensures day-to-day comfort without compromising system logic or solar strategy. As the client put it:
"I'd rather pay for a little power than take a cold shower."

Bonus: Smart Solar Dumping (Coming in V3)

In the next iteration, we’ll enable smart thermal storage:

• Once the battery is full and excess PV is available, Node-RED will raise the geyser’s target temperature — soaking up surplus solar and reducing waste.

Full Integration with Victron + VRM

The system is tightly integrated into the Victron stack:

• View geyser temperature directly in the VRM portal
• Toggle Force Heat remotely via phone or PC
• See energy usage and system status live across all platforms

All logic lives on the GX, so everything continues working even during extended internet loss.

Hardware Used in This Project

Victron Energy System:

• Inverter: Victron MultiPlus II 5kVA
• Battery: 2× Hubble AM5 lithium batteries
• Solar: 3kWp array with 1× 150/35 SmartSolar MPPT
• Controller: Cerbo GX with Touch 50 display

Home Automation Layer:

• Geyser Control: Geyserwise TSE retrofitted with an ESPHome chip for MQTT
• Optional Monitoring: Smart Switch with Tasmota firmware to display real-time geyser power draw

This setup gives the client full control, full visibility, and full peace of mind — no matter what Eskom or the cloud service is doing.

👉 Contact us if you want your geyser to think for itself — and still obey your rules.

🌞 Case Study: Smart Solar Expansion in Langebaan

This Case Study highlights two advanced techniques rarely seen in typical installations:

• The integration of external MPPTs into a hybrid inverter, enabled by Victron's open architecture
• The use of Node-RED automation to extend control logic, protect loads, and optimize self-consumption
  These enhancements turn a great solar system into a highly intelligent, future-ready energy platform.

🔍 Why this is a Case Study

This project is featured as a Case Study because it leverages two non-standard but powerful strategies:

• Hybrid + External MPPTs — Victron uniquely allows external charge controllers to be added to a hybrid inverter system, with full system-level visibility and control via VRM and the BMS.
• Node-RED Automation — Custom logic was introduced to go beyond default inverter behavior, including dynamic load shedding (e.g. stove/geyser control) and enhanced self-consumption logic.

A phased rollout was used to build the system based on actual energy data — but the real value lies in how the system was engineered and extended.

⚙️ Technical Overview

When the client relocated to Langebaan — drawn by its relaxed West Coast lifestyle and the ability to work remotely — they approached us for a scalable solar setup.

The system was delivered in three phases, ultimately resulting in:

• 6kW Victron Multi RS Hybrid Inverter
• 1x 450/80 MPPT (built-in on Multi RS)
• 2x 150/35 SmartSolar MPPTs
• 28kWh battery backup
• 9kW of PV, capable of producing over 50kWh/day
• Cerbo GX with Touch 50 display

This design ensures robust performance, with 90% year-round independence from the grid.

🔵 Why Victron?

Victron’s architecture was key — it’s the only hybrid platform that allows us to scale up solar input by adding external MPPTs while retaining full control and monitoring via the BMS and VRM Portal.

This flexibility made it possible to expand the system’s solar capacity without changing the inverter or compromising stability.

🤖 Intelligent Logic with Node-RED

To elevate system performance even further, we implemented Node-RED automation alongside Victron:

• Self-consumption logic: Maximizes local solar usage before exporting or importing, reducing reliance on the grid.
• Load protection: Relay outputs control the stove and geyser, disconnecting them during low battery or overload to preserve essential services.

This kind of logic would not be possible with a closed inverter platform — Victron’s openness made it viable, and Node-RED made it intelligent.

❄️ Winter-Only Grid Use

In the Western Cape, winter solar production naturally dips due to shorter, cloudier days. During this period, the system may import small amounts of grid power — but for most of the year, the home runs entirely off-grid, thanks to intelligent system design.

Looking to build a smarter solar system — not just a bigger one?
👉 Contact us to discuss how Victron + Node-RED can work for your site.

This large commercial project came to us through a referral from a trusted electrician, bringing us the opportunity to power the West Coast Medical Centre, a two-story facility designed to support a range of medical practitioners. This building, with 14 units for rent, accommodates diverse medical services including general practitioners, ambulance services, oncology care, and more. Collaborating closely with the builder, electrician, engineer, architect, and client, we developed a robust solution to meet the continuous power needs of a busy medical center.

To make the most of available resources, we installed 94x 540W panels across the roof, divided over three MPPTs. The setup includes two DC-coupled Victron MPPT RS units, dedicated to optimizing solar generation for battery storage, and a powerful 27kW Fronius AC-coupled grid-tie inverter, which efficiently directs PV power to cover building loads.

On the backup side, we designed the system with staged expansion in mind, allowing for up to three stages of upgrade, each capable of adding three Victron MultiPlus-II 10kVA inverters in a 3-phase configuration. Additionally, the design supports substantial future upgrades to battery backup capacity as the center’s energy needs evolve. Paired with two 20kWh Freedom Won lithium batteries, this setup ensures reliable, uninterrupted power across the medical center, enabling essential services to operate smoothly regardless of grid reliability.

To enhance functionality, we incorporated custom automation using Node-RED, allowing for intelligent controls and remote management. The system automatically manages fan operations based on temperature and provides the customer with remote access to control air conditioning and geysers outside of business hours. Additionally, excess power is fed back to the grid, letting the center benefit from unused energy. All of this is seamlessly managed through Victron’s world-class VRM app, offering real-time monitoring and control on the fly, ensuring an optimized and highly responsive energy system.

Components:

• 3x Victron MultiPlus-II 48/10000/140-100 Inverter/Chargers in 3-phase;
• 2x Victron SmartSolar MPPT RS 450/2000 Charge Controllers;
• 1x Fronius Eco 27kWh;
• over 50kWp of PV;
• 2x FreedomWon 20/16 Lithium batteries
• Victron CerboGX + Touch70;
• Large Hager AC distribution board, capable of handling 2 more clusters of 30kW Inverter expansions;
• Large 2000A DC busbar system;
• RuviTAG Bluetooth sensor;
• Shelly Relay switch to integrate to Node-RED via MQTT;

Notes:

• ESS enabled with BatteryLife;
• Node-RED enabled to turn AC and geysers on/off on time of day, grid availability and manual button, giving customer option to turn them on/off outside of regular business hours;
• Bluetooth temp sensor to provide temp, humidity and pressure info to system, turning an extraction fan on/off should it be required;

Confronted with critical operational disruptions due to load shedding, our client, a dynamic architectural firm, sought our expertise to restore their productivity. Losing around 4-6 hours of valuable work time daily, they faced not only significant revenue losses but also the burden of excessive overtime to adhere to their project timelines. Their operation, reliant on sophisticated architectural software, high-performance computing stations, commercial printers, and various other essential electrical appliances, required a resilient and reliable power solution. Recognizing the urgency of their needs, we embarked on creating a system that could ensure uninterrupted creative and technical processes.

Components:

• Victron MultiPlus-II 48/5000/70-48 Inverter Charger;
• Victron CerboGX + Touch50;
• Freedom Won 10/8 Lithium battery;

Notes:

• ESS enabled on “Keep batteries charged”;
• Grid meter installed to measure all loads (critical and non-critical) so that when we install panels later, we have a clear picture of required power;

Engaging with a client who not only has a wealth of electrical expertise but also a clear vision for their energy needs was both an honor and a challenge. As a retired electrician, our client knew exactly what they wanted—a state-of-the-art system that could deliver unwavering reliability and efficiency. Their 5-star review stands as a resounding endorsement of our commitment to excellence. We didn't just meet their high expectations; we crafted a bespoke solution that encapsulates the perfect synergy of professional acumen and client insight. This project is a glowing testament to when experience meets precision, resulting in an energy solution par excellence

Components:

• Victron MultiPlus-II 48/5000/70-48 Inverter/Charger;
• Victron SmartSolar MPPT VE.Can 250/70;
• Victron CerboGX + Touch50;
• 8x 545W PV Modules
• 3x BYD Flex 5kWh Lithium Batteries;

Notes:

• ESS enabled;
• With ESS and the energy meter we can supply the non-essentials also with access solar and battery power

For our latest endeavor, we partnered with a client who already demonstrated commendable energy management practices. The goal was not just to address the inconvenience of load shedding but to elevate their energy independence to new heights. Armed with a substantial battery capacity and an expansive solar array, we meticulously designed a system that promises not only to drastically reduce their reliance on grid power but also to harness solar energy with remarkable efficiency. This setup, a blend of foresight and advanced technology, is set to redefine what it means to be self-sufficient in energy usage.

Components:

• Phase 1:
  • Victron MultiPlusII 48/5000/70 Inverter/Charger
  • Victron Lynx Modular Busbar;
  • Victron CerboGX + Touch50
  • SolarMD 14.3 Wall Mount Lithium Battery
• Phase 2:
  • Victron SmartSolar 250/60 MPPT with 8x 400W PV Modules (North)
  • Victron SmartSolar 150/35 MPPT with 4x 575W PV Modules (East)

Notes:

• ESS Enabled;
• With ESS and the energy meter we can supply the non-essentials also with access solar and battery power
• NodeRED Enabled;
• Programmable Relay ON/OFF: Blue Light on condition loadshedding;
• Generator Start/Stop on AC-OUT2: START generator to OPEN (disconnect) power on 95%, STOP generator  to CLOSE (connect) power on 98%. Connected to AC_OUT2 on secondary geyser. Essentially uses geyser as a dump load once battery is full. Also, run this 'signal' via Relay1 on CerboGX and using NodeRED to disconnect during overload;

Embarking on a new journey with our latest client, the mission was crystal clear: to conquer the persistent challenge of load shedding and to significantly slash their grid power dependency. By leveraging the advanced capabilities of Victron technology, we've designed a system poised to revolutionize their energy landscape, setting the stage for substantial efficiency gains and a greener footprint.

Components:

• Victron MultiPlus-II 48/5000/70-48 Inverter Charger;
• Victron SmartSolar Charger MPPT 150/60;
• Victron Cerbo-S GX + Touch50;
• Victron Lynx Busbar;
• Hubble AM5 Lithium Battery;
• 6x 555w PV Modules;

Notes:

• ESS enabled;
• With ESS and the energy meter we can supply the non-essentials also with access solar and battery power
• Node-RED enabled;
• Geyser1 with Geysewise on AC loads
• Geyser2 on Contactor via Relay1 (triggered with NodeRED on SoC and Output power) on Critical loads to use geyser as dump load once battery is full

Upon receiving a commendable referral from a satisfied neighbor, our client entrusted us with a significant challenge: to conquer load shedding woes and usher in substantial energy savings. Opting for quality over cost, they chose our premium services despite our quote being the highest. Embracing this trust, we embarked on a meticulously phased project, utilizing the extraordinary flexibility of Victron's range. The result? A testament to efficiency: a mere 1 kWh drawn from the grid over a remarkable 90-day period (Jan'23 - Apr'23).

Components:

• Victron MultiPlusII 48/5000/70 Inverter Charger
• Victron SmartSolar 150/60 Charge Controller
• Victron CerboGX + Touch50;
• Victron Lynx Distributor
• 3x BYD Flex Lithium Batteries
• 6x 540W Axitech Premium PV Modules

Notes:

• ESS activated on 30% DoD
• With ESS and the energy meter we can supply the non-essentials also with access solar and battery power

Our client, a bustling business in Langebaan, faced a critical challenge: load shedding was costing them 4-6 hours of production every day, leading to substantial revenue loss and long overtime hours just to meet deadlines. With commercial printers, dedicated power stations for the graphics team, and various essential appliances integral to their daily operations, they needed a dependable solution that would keep productivity flowing, even during power outages. We stepped in to design a system tailored to their needs, ensuring that load shedding would no longer disrupt their business or impact their bottom line.

Components:

• Victron MultiPlusII 48/5000/70 Inverter/Charger;
• Solar MD 14.3kWh Lithium Batttery
• Victron CerboGX + Touch50
• Victron Lynx PowerIn DC Busbar

Notes:

• System runs in ESS enabled on "Keep Batteries Charged"