Small Hybrid Power Systems - Victron & Pylontech
Have you ever wondered how much tech you could cram into a small power system? Intelligent Controls built this compact hybrid power system as a fully functional technology demonstrator to showcase the many capabilities unique to Victron Energy and Pylontech in a small, portable package.
What is a "hybrid” power system?
While it's become a bit of a buzzword in the energy sector, the concept behind a hybrid system is hardly new. In a hybrid power system, multiple energy sources work together as efficiently as possible. As more sources are added (solar, wind, hydro, generator, shore power, etc.), more controls are needed to ensure ideal operation.
Today's "hybrid generator systems" run the gauntlet of extremely basic to advanced. In a modern setup, a generator is used as a backup power source, while the inverter/charger and the batteries act as the primary power source. This set up allows for the use of smaller, more fuel efficient generators, reducing fuel consumption and related CO2 emissions by as much as 80% when compared to traditional, generator-only set ups. By adding PV input to the system, generator run time can be reduced even further.
Large-scale Victron-Pylontech hybrid generator system.
One of Victron's strengths is integrated communications between devices via Bluetooth, CAN, or RJ45 connection. As the central comms hub for a Victron hybrid generator system, a Victron GX device coordinates active control of the battery, inverter/charger, solar charge controller, and generator. Each connected device reports data to the Cerbo or other Victron GX device. That data is also pulled into a visual, easy-to-understand dashboard, Victron's remote management portal (VRM).
Summary report on the main system power flows (generator, solar, grid and battery SOC).
The overall goal of these systems is to optimize generator run time and reduce fuel consumption, noise, CO2 emissions, and maintenance costs while incorporating as much renewable energy as possible. The system should be highly reliable, relatively autonomous, and simple to operate. The technology employed in these systems plays a critical role in meeting those expectations - which is why this system design uses Victron Energy components and a fully communicating lithium battery.
The Smartest, Smallest Hybrid System We Could Build
This 120V power system includes a 48V Pylontech US5000 LiFePO4 battery, providing 4.8kW of usable capacity. The US5000 is rated for 8,000 cycles and communicates with the Victron system, which includes a Victron 48V 3000VA MultiPlus II inverter/charger. The MultiPlus II can charge at varying input currents, but its maximum charge rate is 1,700 Watts off of a generator or shore power. A small MPPT Smart Solar 100/20 charge controller is able to receive an additional 1000 Watts of solar. With that amount of power, it’s possible to fully charge this battery in 5 hours on an average day.
While we built this system as a training aid that can be picked up by two people and slid into the back of a truck, this system exhibits all the same functionality you would see in a much larger system. In fact, this basic design could be easily scaled to include up to 96 Pylontech US5000 batteries and a three-phase 180kVA (144kW) inverter system using a total of twelve Quattro 48/15000 Inverter/Chargers.
The core functionality and features of the inverter-battery combination are often overlooked amidst the grandeur of large solar arrays and costly gensets. This hybrid generator system - which can be paired with the most generic 3,000W portable generator - incorporates several Victron-specific features that are worth emphasizing:
Battery Internal ON and OFF Controls
Most systems have significant internal cabling that is powered, even when "Off." A remote ON/OFF connection to the Pylontech battery with a push-to-start and push-to-stop button allows the batteries to be turned off entirely at the BMS level, inside the battery, ensuring maximum safety during transit and no self-consumption during storage.
Optional Automatic Power Off
If there has been no consumption over a set period, for example, 24hrs, the system will power Off and save battery capacity for when it's needed.
Extremely Low Standby Consumption
This inverter has a total power standby of 13W. This means that at night, with minimal loads, the system's self-consumption is extremely low. Beyond that, you can set the Inverter/Charger to operate in “Search Mode” with a self-usage of 3W.
PowerAssist
This function, unique to Victron inverter/chargers, allows you to run smaller input currents while still providing full output power. The input current is adjusted with a toggle switch going to the digital input on the MultiPlus II. Full production with PowerAssist is 3000VA + generator capability. Since the battery assists the generator's output during runtime, it enables smaller generators to operate larger loads. In the case of this MultiPlus 48/3000 120V, the maximum throughput can be up to 50A (6000W) with an active AC input, like a 3000W generator, and the inverter running together.
Solar Charging
In our small hybrid example, we included a small, Victron MPPT solar charge controller. This allows for a deployable solar panel to offer additional charging for the battery bank, as well as being able to offer support to active loads in real-time. In designing a hybrid power system, the options for PV charging include anything from a small single panel to keep the system topped up while not in use to a significant array capable of powering your loads and charging the battery on its own.
Priority Power On Outlet One
Outlet one always retains power, while outlet two is controlled based on the battery state of charge. The goal is to maintain power to critical loads. If a generator fails to start, the critical loads will stay powered up longer. The loss of power on outlet two will indicate to users that they need to start the generator.
Power Up Off Zero Battery Power
If the battery bank is discharged past its low charge cut-off point, the system will shut down and will recover automatically with generator input, or with active solar input from a Victron SmartSolar MPPT.
Automatic Cooling and Ventilation
An internal fan system is synced with the fan on the MultiPlus II itself, paired with one of the relay outputs on the MultiPlus to keep air moving through the entire enclosure.
World-Class Remote Monitoring & Management
A GPS and Wi-Fi antenna are mounted to the top of the box. Through the Victron GSM modem, the system's location can be tracked, and its performance can be monitored and controlled on VRM, Victron's remote management platform, from anywhere within cell service.
Hybrid generator system demo for the US Forest Service National Technology and Development Program.
Use Scenarios
Many of the features mentioned above are beyond what a standard system might include and are often not utilized because people aren't aware of them. In fact, many much larger hybrid power systems don't allow for this level of control.
To understand how some of these features come into play, let's imagine this portable power system is in operation at a Forest Service spike camp during a fire, providing 24/7 continuous power to 2 yurts with small power needs (~5kW) for three weeks at a time.
Scenario 1. The coffee pot is left on all day, the battery is discharged down to 5%, and has turned off the inverter.
The battery won't isolate itself or shut off communications. In fact, we'll still be able to see the system running on VRM since all the devices connected to the battery directly are still powered up. An email notification goes out (low voltage alarm) to whoever you'd like to receive it. The person on site can manually start the generator. Meanwhile, the sun will help bring the system back via the MPPT solar charge controller, and once the batteries get back into the 48V range, the inverter will turn on by itself.
Takeaway: The batteries are not in danger of being damaged, and the system has a way of bringing them back up, and protecting them from excessive discharge. And thanks to VRM, we know what happened vs. wondering what happened because we can see charging vs. loads on site or remotely, as well as the history of the system, meaning we can identify when the load that started the drain on the system actually began.
Scenario 2. The battery isolates itself and no longer communicates state of charge.
Maybe a fuse blew, or perhaps the temperature dropped dramatically overnight. Regardless, we now have no battery in the system. If you plug the system into a generator, however, the inverter will wake up and start to pass power through to the battery. This means that the battery can be woken up by the sun, or by an external power source (in this case, a generator).
If the charge controller is getting power from the solar array, the solar charge controller will power up the DC bus which will power up the comms. As long as the sun is out, you'll have communications - even without a battery, you still get that heartbeat.
Takeaway: A lot of other systems don't work at all if there is any issue with the battery. You are dead in the water until you have 48 Volts. No battery, no go and no communications. This system can operate without a battery - which is tremendously helpful when troubleshooting.
Scenario 3. We're at 8,000 feet with a portable generator that's been sucking dust for two weeks and has a dirty air filter. The generator is struggling and is at a significantly reduced output due to altitude.
If your system is designed around a specific input current and you can't adjust that, you're going to have limited options, and that generator is not going to work for you. If you're in a system where you can adjust your input current, you can keep going. You can do this on the GX touch screen or via a toggle switch. Without Victron’s PowerAssist function, you're stuck with giant generators, even for relatively small systems.
Takeaway: Without PowerAssist, factoring in altitude, and trying to operate efficiently, we'd probably size a 10K generator in order to run at 60-80% at that high altitude, charging at full rate, and running all potential loads. In this system, we can get the same performance with a 3kW generator.
Scenario 4. While powering the camp, there are loads that are very important and loads that are less important.
It's very easy to connect the critical loads to one of the AC outputs that isn't switched and the non-critical loads to an AC output that is switched. If the batteries get below, say, 30%, we can say, "Forget the coffee makers, let's keep the radios online." That gets everyone's attention, but it doesn't compromise the system or its top priority for power supply.
Takeaway: There is a smart, simple way to prioritize loads.
Scenario 5. It's daytime and everyone is at camp using a lot of power. The batteries get low enough to start the generator, but the sun is also shining.
Traditional hybrid systems prioritize the generator power over the solar power when the generator is running. Our system will charge with both sources at the same, prioritizing solar first.
The inverter is good for 35A of charging off of the generator. The sun might be giving us 17-18A of power - why waste that when it can be put to work?
Takeaway: Depending on the generator size, we might charge the batteries twice as fast because we're using two charging sources at the same time. Or, on a nice sunny day, we can leave the generator off for an extra six hours as the PV handles the bulk of your loads, and maybe even charges the battery a bit.
Scenario 6: The system is deployed to multiple sites during a fire season. Each camp has different power demands that might change dramatically over a period of time.
Can you imagine managing dozens or hundreds of hybrid generator systems out in the field and not having the data to analyze what happened and what could be improved? Perhaps, within the first 24 hrs, it's obvious that one particular site needs two systems or a larger system. With good data, we can start making some really smart fleet management decisions before those decisions become critical.
Scenario 7: The system is going to sit for 8 months or a year without use. The person putting it into storage forgets to turn it off.
The system will discharge down to 5% and continue discharging until it isolates itself. (Not to worry; the Pylontech BMS has three levels of protection, preventing damage to the battery cells.) Months later, when the battery does receive an input current, it will wake up and start accepting a charge.
Takeaway: While this isn't great for the battery, it's also not the end of the world, and we're not replacing an expensive lithium battery.
Scenario 8. The system is put away for storage, and it is turned off.
The battery is isolated at the battery itself and stays asleep until it's woken up by an input source or manual operation. On the job site, from the box itself, you can turn off the battery with a switch. This also means that all the internal cables and wires are not powered up.
Takeaway: When the system is 'OFF,' it's really off, simplifying transport and storage.
Conclusion
You can start to understand why Victron Energy is a global leader in the hybrid generator market, offering a very large product mix of high-performance inverter/chargers, lithium batteries, solar chargers, and other products that work together to optimize system performance, allow for remote monitoring and more advanced controls. Paired with Pylontech, the worlds Number 1 Residential Energy Storage System manufacturer with well over a decade of experience in large scale battery manufacturing, the potential for creative energy solutions in the hybrid generator market is nearly limitless.
If you'd like to incorporate any of these capabilities in your hybrid generator builds or have questions about different features you'd like to explore for your unique application, send a message to our R&D team here. We'll schedule a time to discuss what's possible within your application.