Remote Generator Auto Start/Stop using a Victron Cerbo GX
This article outlines how to program a Victron Cerbo GX device to start and stop a generator based on pre-set conditions such as battery state of charge (SOC), Battery Voltage, or AC loads. This added functionality allows you to have a relatively hands-off system.
First, it's worth noting that generators offering auto start tend to be larger and more expensive. It's also common for generators to be oversized for the system they are paired with. With power-assist features built into Victron Energy inverter-chargers, however, a big generator is less of a necessity than it used to be.
A major factor that has changed generator sizing is the introduction of lithium batteries, which usually cuts Generator run time in half because of higher charge rates. Still, running a generator twice as large as it needs to be is not ideal - but sometimes unavoidable because of what's available on the market.
An effective way to reduce generator run time is to program a Cerbo GX to start and stop your generator based on custom conditions. This way, the generator will only be running when told to do so and not wasting costly fuel.
You'll need a two-wire start generator to program your Cerbo for generator Auto Start. Many generators are 3-wire, and in general, Victron triggers a relay that is a normally open/normally closed contact designed to start a generator. If you have a 3-wire generator, there are 3-wire to 2-wire start adaptors. The 3-wire start has a start and a stop signal, while a 2-wire start runs when it's closed and stops when it's open. We can connect you with some of those manufacturers if you want to contact us.
The Cerbo Relay is a Normally Open, Normally Closed Relay. Wire the 2 wires from your Generator to the COMMON and NORMALLY OPEN ports onto Relay 1 of the Cerbo GX.
Next, connect the Cerbo GX to the internet via a hardwired ethernet connection or a strong Wifi connection.
The Cerbo can be programmed from a GX Touch display screen but in this example, we will configure the automatic gen start via VRM, Victron's free Remote Management Portal. The steps are the same on the touch screen and in VRM:
- Log into the VRM portal
- Find your installation and Click on Remote Console. Remote Console provides remote functionality of your Cerbo GX and GX Touch 50 display.
- Go to Settings > Relay. Enable the function for Generator Auto Start.
- Go Back to the Main Menu. Click on Generator Start/Stop and scroll down to Settings.
- Here we have all kinds of options for triggering the auto start.
- Click on Conditions and make your selection to, for example, Auto Start our Generator based on State of Charge Readings.
- Scroll down to Battery SOC and click ENABLE.
Pro-tip: The click-through delay when navigating settings on the Remote Console through VRM can really slow us down. For a quick way to pull up the same view of Remote Console, open a new browser window on your computer and enter the IP address for your device. To find that IP address, scroll to Settings > Wifi > Wifi Networks. Open the network that you're connected to and scroll down to IP Address. (Note you can also find the IP Address from via the GX Touch screen.) Type that same IP address right into the search bar of your second web browser. ***Note: The IP address is specific to the network that you’re using. To pull up Remote Console locally, you must be on the same network that the Cerbo is connected to.
Within Battery SOC, you'll see a variety of options. You can, for example:
- Use the Battery SOC value to start/stop: Toggle this feature on or off.
- Start the Generator when Battery SOC is lower than: Set the depletion level for auto-start.
- Start value during quiet hours: During Quiet hours it may be desirable to delay an auto-start until it really can't be avoided. If Quiet hours have been defined, set a lower, more critical, autostart level.
- Stop when Battery SOC is higher than: Set the recharge level for auto-stop.
- Stop value during quiet hours: If Quiet hours have been defined, set a lower auto-stop level to achieve a shorter generator run-time.
For example, let's say we want to start the Generator at 20% SOC and stop at 95% SOC. We also want to start the Generator at 10% SOC during Quiet Hours. If the batteries are in danger of getting drained in the middle of the night, running the Generator is a good idea. Here in VRM, we can establish our quiet hours, the low SOC value, and then the STOP value of SOC to turn off the Generator at a particular SOC. It's always a good idea to double-check that the conditions have been entered and to do a test run of how the system will operate.
If you feel your SOC reading is unreliable - as we see from older batteries or low-quality lithiums - you might program the generator to autostart based on Battery Voltage as a backup to SOC. The idea is that if the battery voltage gets to X, start the Generator regardless of the state of charge. It's worth remembering that SOC is a calculation that can get thrown off for a number of reasons, including capacity fade, unbalanced batteries, old and dying batteries, and wiring issues.
Another example of conditions for programming would be based on AC loads. If you have a big load, you can start the generator to provide additional power to the system as long as the generator has sufficient time to power up and sync up before an overload occurs. This is a good option if you have a time frame when large loads are likely to deplete the battery significantly, in which case, you'll have to start the generator regardless.
Pro-tip: Victron Energy recently added a remote switch that you can access right from VRM which allows you to start and stop your generator. This is a useful tool that maximizes control of your system from afar.
MultiPlus or Quattro?
The two primary lines of Victron Inverter/Chargers are the MultiPlus (or MultiPlus II) and the Quattro. The main difference between them is that the MultiPlus has one AC input while the Quattro has two AC inputs. The MultiPlus line is best suited for applications where you have only one AC input. Some relevant situations might be: an off-grid home with one generator as backup, a grid-connected home with no generator as backup, a mobile application like an RV with or van with shore power, and no generator. The Quattro is best suited for applications with multiple AC sources, such as; a grid-connected home with a backup generator, an RV with a generator on board, an off-grid home with a primary generator and a backup generator, etc. The Quattro also offers higher power output options suited to 120V systems, though both may be configured for use in parallel, split-phase, or 3-phase systems. Still choosing the right inverter/charger for your set up? Read our Victron Energy Inverter/Charger Buyer Checklist.
We are always looking for ways to improve system efficiency, whether that's appropriately sizing generators, introducing energy-dense lithiums, or adding custom controls to better monitor battery status and reduce generator run times.
Related reading >>> Why LiFePO4 batteries became our go-to for off-grid & backup energy systems