Installation guide to connecting a Redflow battery array to a Victron Energy system

Simon Hackett
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This is a step-by-step guide to connecting a set of Redflow ZCell/ZBM2 batteries to an energy system using Victron Energy components.

This is a differences guide only!

It assumes you already know how to set up a working Victron Energy system (and how to set up and use ESS if it is an on-grid system). 

The installer must is already be trained in the design and installation of Victron Energy based systems. If this is not the case, they need to undertake Victron Energy system training first.

Redflow is not a Victron Energy training provider - Redflow's own training is differences training (as is this installation guide). It assumes you, as an installer, already know how to install a Victron based energy system based around a smart (e.g. Lithium and Lithium BMS) based battery - or at the very least using a conventional Lead-Acid battery.

Prerequisites

You should also re-check and further update these system components at regular intervals. These system elements and their functionality and feature sets are regularly improved over time by both Redflow and Victron based on learnings obtained and issues resolved in the field.

The system components to check - and the recommended minimum firmware versions for each - are as follows (as at September 2019):

  • CCGX / Venus GX : Version 2.23 or later : check the Settings->Firmware page
    • Note: The GX platform auto-updates itself by default
  • MultiGrid/MultiPlus/Quattro flash firmware : Version 462 or later
    • These devices should be upgraded using the Victron VE.Flash tool.
    • Flashing the firmware removes all 'Assistants' and also removes any multi-unit cluster configurations, so these need to be re-loaded following any flash updates
  • MultiGrid/MultiPlus/Quattro systems need to be running the latest ESS Assistant (only required for on-grid deployments):
  • MPPT DC solarcharger units need to be upgraded to their latest firmware release using the VictronConnect tool or online using the VRM portal 'Device List' remote upgrade function
  • The Redflow BMS needs to be running the latest release (1.7.0 or later).
    • Use the Tools->Upgrade BMS page to check and upgrade the BMS 
  • ZCell batteries should be running the latest released battery firmware (32.18.00 or later).
    • The latest recommended battery firmware is carried inside each BMS software release
    • If battery firmware needs updating, a yellow caution triangle will be shown beside the firmware version number on the main BMS status page
    • Use the Tools->Upgrade Battery menu item to upgrade the battery firmware if required

Once all system elements are upgraded, follow these instructions:

Install and configure ESS for use with ZCell systems (on-grid installations only)

Note: ESS is not required and generally not installed in off-grid installations.

Use VE.Configure to load in the "ESS Assistant" to your Multi/Quattro just as you would for any other ESS based Victron installation, in accordance with:

https://www.victronenergy.com/live/ess:design-installation-manual

Download and work through the annotated screen shots in the attachment to this article. This shows a typical set of screen shots as one works through the VE.Configure pages to load and configure the ESS Assistant into a Multi or Quattro.

It is important to load these voltage and other assistant settings as noted in the attached guide.

If these are not set correcting the system may not operate correctly.

Notes:

  • These screen shots are from an earlier ESS Assistant version (sorry - will be updated later). The latest versions require you to enter the battery capacity in Amp-hours into the Assistant as well. Use 200Ah per ZCell - e.g. for a  (say) 4 battery system, use 4 x 200 = 800 Ah. 
  • The voltages in the cutoff table are non-critical as long as they are less than 42V.
  • The sustain voltage is non-critical as long as it is 40V or less (40V works fine too).
  • The settings for downstream PV should be 'as appropriate' for your system.
  • There is no need to adjust other charger voltages or battery type in VEConfigure after loading the assistant, as the DVCC function overrides all the other firmware voltage/current settings in practice once it is enabled and active using CANBus
  • As for all ESS based systems, the ESS Assistant must be loaded into all Multi/Quattro units in a multi-unit system.

Enable the Victron DVCC mode (for all ZCell systems)

The Dynamic Voltage and Charge Current mode is designed for 'smart' battery systems that communicate via CANBus from a BMS to the CCGX (such as the Redflow BMS and ZCell units)

DVCC is appropriate for and recommended for use with both On-Grid ESS and Off-Grid (non ESS) Victron Energy systems. 

DVCC enables the system-wide dynamic control of current and voltage limits based on BMS information.  It is  a major enhancement in how Victron Energy systems operate.

The charging cycle for batteries is no longer based on the old 'lead acid' notion of initial/bulk/absorption phases. Instead, the charging control systems enage (and switch between)  Constant Current (CC) and Constant Voltage (CV) target modes, as DC bus conditions change.

The DVCC control mode is ideally suited to the operation of smart batteries with near-linear charge/discharge characteristics such as the Redflow ZCell.

Note that on-screen displays when DVCC is operational show 'Absorption' when in CV mode, and 'Bulk' when in CC mode.

Note: Older model Victron Energy based MPPT solarchargers (that don't have VE.Direct connection paths) do not support DVCC. All the VE.Direct based units do support it. Only use VE.Direct MPPT models for new installations.

With those pre-requisites undertaken, and with CANBus communications from the BMS to the CCGX screen already operating (as per other knowledge base articles), turning DVCC on is easy: 

  • In the CCGX Setup -> System Settings menu, turn on DVCC (as per the screen shot below)
  • Then under the DVCC switch, please turn off SVS (This option will appear directly under the DVCC item when you enable DVCC):

CCGX-DVCC-on-SVS-Off.png

 

Note: SVS is 'shared voltage sense' - an intended improvement to the way the Victron Energy system senses bus voltage. However, SVS is (at the time of writing) incompatible with the ZCell battery and BMS operating cycle and- hence ... just turn it off.

If SVS isn't turned off, the system will 'hunt' in terms of target voltage and current over time and will be unable to smoothly bring a ZCell through its post-maintenance pre-charge phase to start to charge it up again.  Leaving SVS on may also lead to system voltage surges during substantial changes in bus operating conditions over time, with the potential for intermittent ZCell protective shutdown/restart cycles occurring as a result. 

Other Post-Installation Settings to adjust in a Redflow installation

ESS MinSoC

Note that for correct system operation, the Settings->ESS menu 'Min SoC' value must be set to 0% in single-ZCell systems.

This value can, if desired, be set to a non-zero value (but generally not above 50% in multi-ZCell systems). This is to ensure that it is possible for the discharge/maintenance cycle required by the ZCell to operate properly. 

In a single ZCell system where MinSoC is desired to be non-zero, consider instead the use of the CCGX 'Scheduled Charging' feature (a sub-menu under the ESS Menu) to perform a baseline charge once a day at a time that still allows for the battery to discharge for maintenance successfully when required.

ESS Operating Mode

It is important to ensure the Settings->ESS Menu 'Operating Mode' is set to 'Optimised (Without BatteryLife)' and not set to 'Optimised (With BatteryLife)' 

The Victron Energy 'BatteryLife' feature is incompatible with the need to fully discharge the system periodically in a single ZCell environment.

In a multiple ZCell installation, BatteryLife might in principle be able to be used, but Redflow recommends that BatteryLife is disabled in all Redflow installations for various reasons reasons, including to ensure that battery maintenance cycles can be performed efficiently.

ESS-Menu.png

Quattro/Multi 'Low Battery' Alarm 

You should disable the 'Low Battery' alarm for your Quattro/Multi environment to avoid swamping your CCGC display with spurious Low Battery alarm notifications each time your system is performing battery maintenance.

You can find this setting by selecting your Multi/Quattro on the CCGX menu and navigating to the 'Alarm Setup' sub-menu, and then setting the first alarm in the list, 'Low Battery', to Disabled

llow-battery-alarm-disabled.png

System Timezone

That the CCGX picks up NTP based (Internet-synchronised) time automatically, but you do have to tell it which timezone it is physically installed into.The system timezone should be set correctly under the Settings->Date & Time menu, to obtain accurate (local time) based logging information and so the time shown on the on-screen CCGX display is correct. 

In case of problems

First, do check to make sure you have made all the setting changes noted above!

Next, you can try upgrading firmware (including in the Multi/Quattro and in the BMS) to the latest released versions first. A very wide variety of issues are dealt with and handled in improved ways in newer software releases.

Also do check the diagnostic advice under the 'Victron Energy Troubleshooting' section of this Guide Centre - as a number of common operational issues and their solutions are covered there. 

 

 

 

 

 

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