Introduction / Important Note
This article explains how to interface Deye Low Voltage Hybrid Inverters with Redflow BMS+ZBM clusters.
This documentation is limited to explaining the differences and requirements to interface Redflow ZBMs rather than Lead-Acid or Lithium batteries into an otherwise standard Deye based energy system.
If you plan to integrate Deye products into energy systems, you need to obtain appropriate training to do so.
Redflow does not offer Deye system integration training generally, nor does it offer Deye operational support. Redflow's ambit here is limited to ensuring that the Redflow BMS+ZBM combination are successfully interfaced and able to transfer energy to and from the Deye products.
For successful operation:
- The Redflow BMS must be running BMS version 1.13 or later
- The BMS has to remain powered up during the 'Battery Activate' process noted later on
The Redflow BMS must be cabled to the Deye device using a CANBus cable.
There is an RJ45 CANBus input socket on the Deye device.
The simplest way to make a cable is to cut one end from a standard RJ45 cable and wire the appropriate wires into the Redflow BMS screw terminals.
As per the diagram below, the relevant pins on the inverter-side RJ45 plug are pins 4, 5 and 6.
Simply connect these to the labelled screw terminals on the Redflow BMS.
(The ground pin is actually optional - CANBus cables will work without it)
Redflow BMS Configuration
Beyond normal BMS and CANBus configuration, one checkbox needs to be turned on, in order for the Deye unit to successfully 'activate' a totally discharged battery. This checkbox becomes available in Redflow BMS version 1.13 onward.
The checkbox is under 'Config->EMS Integration', on the 'CANbus' tab.
It is called "Send Override Values to Support Black Start".
Simply turn this on and hit 'Submit' - see screen shot below:
This flag causes the BMS to send appropriate synthetic voltage reading values to the Deye inverter when the ZBM battery array is totally discharged. This functionality is required for successful use of the Deye the "Battery Activation" function, and ensures that it operates in a stable and repeatable manner with Redflow ZBMs.
Deye Unit Configuration
Review all configuration pages and consider appropriate settings for your Redflow battery array.
Review especially all tabs under the 'Batt Setting' pages.
On the page shown below, configure as follows:
- Batt Capacity in Ah set to "Number of ZBM's x 200"
- Max A Charge set appropriately (it acts as a global constraint that overrides CANBus-sent values)
- Max A Discharge set appropriately as well
- "Batt Mode" set to "Lithium'
- 'Activate Battery' is checked
On the 'Batt Setting' page shown below, the Lithium Mode should be left at 00 and the shutdown/restart percentages set to values reasonable for Redflow batteries (note all values can actually be set to 0%):
Make sure to set the grid settings page appropriately to your AC grid standard (e.g. AS4777 for Australia):
Verifying CANBus Communication
You can verify that the Redflow BMS is sending CANBus data and that the Deye is properly 'hearing' it by bringing up the battery status page (see example below).
A page display that is showing a different output format to the below (and a lack of useful data) indicates that the CANBus communication process is not yet operating correctly.
Battery "Activation" (black-start of a fully a discharged Redflow array)
The Deye product has a 'Battery Activation' function, designed to recover batteries that have run flat. This function operates to successfully bring up a Redflow battery array from empty (zero volts).
The battery 'Activation' function does not commence operation until the unit has been powered up for ten minutes.
At the ten minute mark and providing the unit has a reason to charge generally (see next point), the system starts to slowly ramp up the DC battery bus voltage.
The process of ramping this voltage can take a few minutes, before the voltage rises to the point where the Redflow system is able to complete its normal 'bubble purge' and 'pre-charge' functions and then commence normal battery functionality.
Two examples of conditions that will lead to the system Activating and then charging the battery (after ten minutes) are:
- DC solar is present at a power level exceeding local site energy demands (i.e. 'surplus solar' exists); OR
- There is an AC grid connected and the system has been programmed to undertake grid-based charging of the battery
Battery Activation Limitations and Workaround
Some Deye products have hardware limitations that can stop the 'Battery Activation' function from working properly.
In particular, older Deye units (manufactured prior to mid 2023) will not activate a battery from the AC grid input.
There is a workaround to resolve this issue, if required.
It uses a 'Support Power Supply' that is attached to the DC bus.
In all cases, it is highly recommended that current generation Deye hardware be used, as this should avoid these limitations being a factor.
Notes on Fault/Warning indications
- An "F31 AC SlaveConductor_Fault", should it be shown on the "Device Info" (alarms/warnings) page of a Deye unit, just means that there was an unsuccessful attempt at a Battery Activation cycle. These cycles re-try automagically, and no action is required in response to this fault indication as such. If activation repeatedly fails, review the activation limitations notes (above).
- A 'W31 Battery_Comm_warn" warning, should it be shown on the Device Info page, indicates that the battery activation process was interrupted due to an unexpected value being sent by the Redflow BMS to the unit. This generally implies that the Black Start support flag (see above) has not been enabled in the Redflow BMS. Turn that flag on and try again.
- If the battery electrolyte temperature is below 15C the system won't be able to complete the initial activation from empty until that temperature rises above 15C. Once the battery starts to charge, it can keep itself warm 'on its own' from then on (even if the ambient temperature falls far below 15C).