In some regions, brown-outs, black-outs or load-shedding have become an unfortunate part of daily reality. The presence of a stable electricity grid is not as common as it should be. Fortunately there are now affordable and scalable solutions that provide uninterrupted clean power from the smallest homes to the largest luxury villas.
Back-up systems seamlessly switch over from (failing) grid power to battery power so fast you and your most critical appliances won’t even notice. The system is sized to power the critical loads during the expected ‘down times’. Solar energy can extend the up-time and if needed, a generator can be seamlessly integrated, minimising their usage automatically by prioritising solar energy.
The energy consumption is calculated by adding up the sum of the essential consumers X the expected duration of a black-out. Add all the Watts of the simultaneously used consumers to calculate the required peak power.
In existing installations, ask your installer to install an energy logger to make a blueprint of your real-life energy behaviour, to exactly know what to plan for.
A walk-through of Design Considerations
for a small residential Back-up System.
There are many reasons why to choose for either technology. But let’s have a quick glance at the cost-effectiveness and the practical differences.
When choosing an off-grid battery bank there is primarily the choice in technology: lithium or lead-acid. For off-grid applications, Lithium has quickly become the new standard in larger (residential and commercial) systems because of performance reasons, but also due to their lower cost-per-cycle. For smaller systems the lower cost-per-cycle situation is also true, however the higher upfront investment led many to consider Lead-acid batteries. Due to a continuous downwards price pressure, the tipping point towards Lithium for small off-grid systems is closer than ever and in some regions already there.
Victron Energy offers full flexibility when it comes to selecting an off-grid battery bank of choice. Next to our own range of quality batteries, the choice includes a number of well supported third party Lithium battery manufacturers that can be easily integrated through the use of a GX-device. This flexibility enables our customers to perfectly match their off-grid needs for their unique power situation.
Check the manufacturer's data sheets for the expected cycle life and see what works in your (business) case. Each manufacturer comes from a different background and each may have it’s pros and cons for your local situation (availability, support, performance in hot/cold climates, installability, pricing, etc). Therefore, feel free to reach out to a nearby Victron Authorised installer and ask for their local know-how.
Pylontech US2000 LiFePO4 48V 2400Wh + Cerbo GX: this Lithium module offers a cycle life of ±6000 cycles, before degrading to 80% capacity. It can roughly deliver an effective total of 2 kWh on a system voltage* of 48V to power the loads during a 2,5h black-out (2400kWh * 80% discharge capacity) and can be easily scaled, may the demands for back-up power rise. When using a third party Lithium bank, a GX device is mandatory, such as the Cerbo GX. Integrated through a CANbus interface, the GX device is used to set up, manage charge and discharge limits and to exchange error codes and state of charge information.
Back-up systems don’t need solar when the batteries are sized properly. However, it can be used to extend the uptime of your system. In an event of a day-time black-out, solar can be used to power a percentage of the loads directly, complemented with energy from the batteries. It is also possible to scale up and power all loads directly from the sun.
Victron Energy solutions come with the advantage that they are modular and extremely flexible. Therefore, you can build your system in line with your budget and grow it in line with your ambitions over time. So the solar array can be installed at commission or later.
Any percentage of solar energy between zero or scaling towards a self-consumption system where the loads are fully powered by solar works. You can build this at commission, or over-time, choose a matching MPPT controller or add another later. The solar yield is also a seasonal thing. In summer there is a better yield than in winter. You could for instance decide to start with 50% of the goal-size solar array in summer and add the other 50% in winter, or install it all at once.
Geographical location data and panel orientation must be considered.
In the end, how far you wish to move away from the grid depends on your budget and the available physical (roof) space. The larger it is sized in the direction of your actual energy consumption, the more you are lowering your utility bills and improving the cost-effectiveness of your system.
Many customers may already have a back-up generator in place, on which they now fully rely on during black-outs. With the Victron Energy hybrid generator concept you can now become a whole lot less reliant on these noisy, fuel consuming, maintenance heavy polluters. In the hybrid concept, the battery bank and the inverter take the primary role to power the critical loads in case of a grid-failure. Only when the back-up batteries reach critical levels (in case of a long black-out), the system can be programmed to auto start/stop the generator, which will then power the loads and charge the batteries back to a certain percentage. With this hybrid concept, your fuel and maintenance bills go down significantly.
Thanks to our inverters with PowerAssist, you can now also choose a smaller generator, the inverter will use additional energy from the battery to power peak loads. With our long list of possible settings to auto start/stop the generator from the GX device, you can even program the system with generator-free times, to avoid the genset from being started in the middle of the night.
GX-devices are the communication centre of an installation, giving you perfect control over all systems components and maximise their performance, no matter where you are. They are also essential to integrate a third party Lithium battery bank.
Through our free VictronConnect app and the Victron Energy Remote Monitoring portal or laptop, you can check the system from local and remote. Monitor the battery state of charge, power consumption, power harvest from PV, generator and mains, or check generator tank levels and temperature measurements. Catch potential issues early by programming alerts and alarms in order to prevent definitive system failure.
To add remote connectivity, the GX device can join an existing WIFI connection. Otherwise, a GX LTE 4G can provide a mobile internet connection for the system and connection to the VRM Portal. It works on 2G, 3G and 4G networks. Smaller systems without GX can do with the GlobalLink 520. It connects 2 VE.Direct enabled devices to VRM without any monthly fees or subscriptions, for the first five years.
Large energy consumers such as washing machines, pumps, air conditioning, or electric stoves may become a challenge for a limited backup capacity of the battery bank and can probably wait until the grid is back. Most of our inverter/chargers come with 2 AC-outputs, one for the critical loads (lights, fridge, TV, alarm systems, etc) and the second AC output for non essential loads. This way, your battery capacity is ready for the essential loads and your system can be sized in the most cost-effective way.
To improve the cost-effectiveness of a back-up, ESS or off-grid system, it’s worth taking a look at the energy consumption side, rather than having to size (and finance) a system to power inefficient devices. A recommendation would be to work with appliances that have an A+ energy rating or ideally higher (A+++) to minimise the use of electrical energy, especially for the larger consumers (Fridge, inverter air conditioners and choose LED lights). It is not uncommon for certain regions (Africa for instance) to choose alternative forms of energy for cooking and (water) heating, such as solar water heating systems or gas, reducing the need for electrical power.
How do the system design considerations translate into a robust system?
Every ‘household’ appliance or ‘heavy duty tool’ you would expect at home or at work can also be found in independent energy systems. All these devices need an Alternating Current (230V or 110V) to run.
Some of these devices such as computers can be sensitive to the quality of the inverted power (bad shore- or generator AC-input power can influence this quality negatively). Motor driven or heat generating equipment may require a high start-up current. All our inverters produce a pure sine wave, even when the AC input quality is less good, ensuring that sensitive loads can be powered and enjoy a peak-power of generally 2x of the inverters rated capacity to power even the heaviest of loads, or basically any load, problem free.
A recommendation would be to work with appliances that have an A+ energy rating or ideally higher (A+++) to minimise the use of electrical energy, especially for the larger consumers (Fridge, inverter air conditioners and choose LED lights).
Examples of AC-devices:
Generators produce mostly AC current to offer independent electrical power where needed. They help charge the batteries and power the (peak)loads in case of grid or shore power shortings or failure.
In all cases, Victron Energy solutions can help you reduce the reliance on these noisy, fuel consuming and maintenance heavy generators, providing an eco-friendly and cost-saving alternative.
Some smaller systems can now just run on batteries, other systems can do with smaller generators, or less generator time. For larger systems, generators may be an unmissable component in the setup, but the dependence on them can be reduced, for instance by adding solar power or battery back-up power, only using the generator when the state of charge is too low, or the (peak) power demand too high.
Victron Energy systems are recognised in the market for their great ability to master hybrid generator concepts, which comes with several advantages:
Inverter/charger/MPPT convert DC power from the batteries to AC power, safely powering appliances or heavy duty tools with 230V (or 110V in other markets) and take power from the solar array to charge the battery and/or power loads directly. Their built in charger uses grid, shore or generator power, using the best adaptive charge algorithms for your batteries of any kind.
All Victron Energy inverter/charger/MPPT are developed for professional duty, enjoy a reputation of extreme resilience and are built on decades of field experience in the most demanding conditions. Our extremely resilient inverter/charger/MPPT are the best choice when both inverting and charging from AC inputs (such as shore or grid power, generators or AC-PV inverters) are required and grid usage is to be minimised by adding solar power.
The service battery, also called a house battery or battery bank, stores power for the system's consumers, providing autonomous power especially for moments when input power sources aren’t (fully) available.
Victron Energy offers several battery technologies, all designed for professional performance, reliability and long service life in the most demanding environments. They come with a 2 year worldwide warranty and our datasheets offer a fair picture of the performance and expected life cycles, meaning no investment surprises along the way.
Victron Energy also offers full flexibility when it comes to selecting an off-grid battery bank of choice. A large number of well supported third party Lithium battery manufacturers can be easily integrated through the use of a mandatory GX-device. This flexibility enables our customers to perfectly match their off-grid needs for their unique power situation. When working with unsupported brands, a Victron Energy Battery Monitor is required to pass on accurate state of charge readings to the wider system.
While there are multiple technologies to choose between, the main choice is between lead-acid and lithium which mainly depends on the expectations of the performance, cost-per-cycle and physical aspects (size/weight).
The above probably cuts 45 years of battery development expertise a bit short, for more info check our deep dive.Deep dive: Lithium or lead-acid Check which third-party battery banks are supported
Solar panels catch the energy from sunlight and forward it to a solar charge controller which stores that energy in the systems battery bank. Adding solar panels to your system means free energy, independence from the grid and allows you to downsize or eliminate the need for noisy, fuel consuming and maintenance heavy generators.
Victron Energy offers a wide range of highly efficient solar panels that have exceptional low-light performance and high sensitivity to light across the entire solar spectrum, making it the perfect choice for any system. Victron Energy solar panels meet the most stringent safety requirements and their limited warranty means no surprises along the way.
All Victron Energy smart products can be monitored and controlled from the palm of your hand. Just connect the VictronConnect App via Bluetooth and you’ll have direct access to the performance data of your system. You can also easily change settings, turn devices on or off and much more.
Non-smart devices with a VE.Direct port can also become smart, through the use of the VE.Direct Bluetooth Smart dongle
It is also possible to monitor and control your system remotely. VictronConnect-Remote functionality enables Victron products with a VE.Direct interface to be accessed remotely through a GX product, via the VRM online portal. This powerful feature allows full product configuration and monitoring from practically anywhere in the world using the VictronConnect app. The user interface experience is just like the products were connected locally using Bluetooth or a wired VE.Direct to USB interface.See what the VictronConnect app can do See our GX-devices
Monitor and manage your Victron Energy systems from anywhere and catch potential issues early by setting alerts and alarms. With VRM you are always in perfect control from wherever you are.
VRM works with a GX-device such as the Cerbo GX with internet connection, the GlobalLink 520 or GSM LTE 4-g for smaller systems.
Monitor the battery state of charge, power consumption, power harvest from solar, generator and mains in real-time. Optimise the energy harvest and usage with history graphs and detailed analytical reports. Catch potential issues early by setting alerts and follow up on alarms to prevent definitive system failure.
Easily control the shore power input current limit, switch on the inverter, (auto)start/stop generators or even set quiet periods to avoid starting the generator in the middle of the night. With VRM you can change any setting, follow up on alarms, perform diagnostic checks and resolve challenges from wherever you are.See all our GX-devices
Our modular, robust and connected off-grid systems have been proven to deliver unequalled reliability time and time again, even in the harshest of climates. But it’s our unique combination of up-to-date hard- and software, intelligent monitoring Apps, the network of highly trained Authorised professionals and widespread repair centres that turns a Victron Energy system into an unbeatable system, that is Powered by know-how.
When making power supply investment decisions, calculations purely based on price can be deceptive. Their true performance and expected service life cycle are equally important. Good thing Victron Energy equipment lives up to their specifications, both in terms of performance and expected life cycle (when used as designed). Our 5 or 10 year warranty and fair and fast repair policies mean your investments are protected and under most circumstances, won’t let you down.
With battery based power systems, efficiency is always key to providing great levels of cost-effectiveness. From our incredibly efficient SmartSolar Charge Controllers to the way our inverter/chargers can provide a super efficient Energy Storage or off-grid system, or how complete systems are optimised by our GX devices: with a Blue Power system you can be sure that all the details are thought through and that our products live up to their (efficient) specifications. This, combined with our reputation for extreme resilience and expected life cycles, translates into cost-effective solutions, especially when compared to ‘cheaper’ options.
By replacing generators with solar energy as the primary source of power, power security is increased, maintenance reduced and overall energy costs lowered to a tipping point where independent energy systems enable a whole new generation of business models. By providing sustainable power at scale new business opportunities are within easy reach, even at remote locations where there is no grid present at all. Fish farms or entire factories and resorts can be started or converted, wherever it is needed. The positive social and economic advantages are substantial and far-reaching and with Victron Energy you can power it all.
Our global network of ±1000 highly trained distributors, installers and service partners are always on hand to help. From stock advice, installation recommendations, after-care and technical support. With the Victron Energy team, their partners and lively community you can always be sure the power of know how is by your side.
Thanks to our customer feedback loop, data and knowledge sharing, we innovate 24/7. We are powered by know-how, it keeps us going and our users going - ensuring peace of mind in off-grid for years to come.Check our community See how we achieve peace of mind in off-grid
Do you have a question about a product, or do you wish to have a system installed on-site? Your local Victron dealer is trained to translate your exact needs into robust solutions.
Thanks to the help of a carefully selected and well trained global network of Authorised dealers, our customers can count on a swift service and our large, worldwide repair network that covers even the most remote areas with a fast service.