5. Monitoring and control

In this section:

5.1. Monitoring and control via VictronConnect

The battery and BMS are monitored and controlled using the VictronConnect app.

VictronConnect has three pages for this purpose: a status page, a battery page and a history page. The individual parameters are explained below.

Status page:

The status page provides information about the current battery and BMS status.

State of Charge: Shows the battery charge level in percent.
Mode: Displays the system status (On or Off) and allows powering off the system with a tap.
Allowed to charge: Shows the BMS status for Allowed to charge. Reasons why the status shows "No" are as follows:
- Battery temperature below 5 °C.
- Battery temperature too high.
- One or more battery cell voltages have reached the high cell voltage threshold (hardcoded in the battery).
Allowed to discharge: Shows the BMS status for Allowed to discharge. Reasons why the status shows "No" are as follows:
- The configured Discharge floor has been reached.
- One or more cells reached the hard-coded low cell voltage threshold.
Note that "Allowed to discharge" will show "Pre-Alarm" in the event of a pre-alarm.
Voltage: The battery voltage as reported by the battery.
Current: The battery current that is currently flowing, as reported by the battery.
Power: The battery power as reported by the battery.
Consumed Ah: Consumed Ah since last full charge cycle.
Time remaining: The time that remains at current consumption until the defined Discharge floor is reached.

Battery page:

The battery page provides information about the installed battery bank and gives more detailed information about each individual battery.

Battery bank info

Balancer status: Shows the battery balancer status. Possible states are:
- Unknown: The current balancer status is unknown. Reasons for this could be:
  - The battery has not been fully charged for more than 30 days.
  - The battery has just been added to the system.
  - State of charge is unknown.
  In all cases, start a new charging cycle.
- Balanced: All battery cells are well balanced.
- Imbalanced: An imbalance has been detected between one or more battery cells. Start a full charge cycle to balance the battery.
- Balancing: The battery is currently charging and the cells are being balanced.
Min cell voltage: Displays the lowest cell voltage detected in the battery.
Max cell voltage: Displays the highest cell voltage detected in the battery.
Min cell temperature: Displays the lowest cell temperature detected in the battery.
Max cell temperature: Displays the highest cell temperature detected in the battery.
Batteries: Number of batteries installed in the system. This is automatically recognised by the BMS.
Battery cells: Number of battery cells in total. This is automatically recognised by the BMS.
Batteries in series: Number of batteries connected in series configuration. This is automatically recognised by the BMS.
Batteries in parallel: Number of batteries connected in parallel configuration. This is automatically recognised by the BMS.
Individual battery info
The lower half of the battery page contains specific information about the selected battery. If there is more than one battery installed, the respective battery can be selected using the "Battery number" selector.
The information for each individual battery is: battery serial number, nominal capacity, firmware version, battery temperature, battery voltage, battery current, individual cell voltages.

History page:

The history page shows information about the battery over time since installation or since the history was last reset.

Deepest discharge:
Cumulative AH drawn:
Discharged energy:
Charged energy:
Synchcronisations:
Cycles:
Last full charge:
Minimum battery voltage:
Maximum battery voltage:
Min cell voltage:
Max cell voltage:
Min battery temperature:
Max battery temperature:

5.1.1. Instant Readout

VictronConnect can display key smallBMS NG data directly on the Device List page—without needing to connect to the product. This includes visual notifications for warnings, alarms, and errors, allowing quick diagnostics at a glance.

Available parameters:

Battery voltage
Battery current
State of charge
Remaining time
Battery temperature
Consumed Ah
Visual notifications for warnings, alarms and errors

For details on enabling Instant Readout, refer to the VictronConnect manual, available on the VictronConnect download page.

5.1.2. Reset to factory defaults

The smallBMS NG can be reset to factory settings via the VictronConnect app.

How to reset:

Open VictronConnect
Tap the cogwheel icon to access Settings.
Tap the three vertical dots in the Settings menu.
Select Reset to defaults, then confirm with Yes.

The following settings will be restored to their default values:

Charged voltage
Tail current
Charged detection time
Low SoC warning level
Discharge floor

5.2. LEDs, warnings, alarms and error codes

The BMS is equipped with two LEDs: the Bluetooth Status LED and the Error LED. These indicate the current operating state as well as any faults.

Warning, alarm and error codes are reported via the VictronConnect app.
A warning indicates a problem that, if not corrected, will result in a system shutdown, while an alarm indicates the reason for the system shutdown.

The following tables list all LED, warning, alarm and error codes:

Bluetooth Status LED	Description
Off	No system power or Bluetooth is disabled in the VictronConnect app.
Blue on	A Bluetooth device is connected.
Blue blinking	Bluetooth is active but no device is connected.

Error LED	Description
Off	No warning/alarm/error active.
Red blinking	A warning is active.
Red on	A alarm and/or error is active.

Warning codes

VictronConnect warning code	Message	Instructions / Remarks
W-B01	Low cell voltage	Charge the battery or reduce the load to prevent an imminent system shutdown.
W-B05	Communication with battery lost	Check the cables between BMS and Battery.
W-B07	Low SoC	Charge battery or reduce load to prevent imminent system shutdown.

Alarm codes

VictronConnect alarm code	Message	Instructions / Remarks
A-B01	Low cell voltage	Charge battery. The system will turn the loads back on when the battery is sufficiently charged.
A-B05	Communication with battery lost	Check the cables between BMS and Battery.
A-B07	Low SoC	Charge battery. The system will turn the loads back on when the battery is sufficiently charged.
A-B08	Low bank voltage	Charge battery. The system will turn the loads back on when the battery is sufficiently charged.
A-B09	High battery temperature	The battery temperature is too high for charging. Try to reduce the ambient temperature.

Error codes

VictronConnect error code	Message	Instructions / Remarks
E-B01	Battery configuration invalid	Check VictronConnect ´Battery´ tab for more details. Check if batteries BMS cables are all connected
E-B05	Battery configuration invalid	Check VictronConnect ´Battery´ tab for more details. Check if batteries BMS cables are all connected.
E-B09	Battery voltage not allowed	The battery voltage is too high or too low. Check the battery voltage and check the battery settings in the VictronConnect app. This error occurs when the battery voltage is outside all system voltage ranges (9V > Vbat > 60V)
E-B11	Hardware error	Contact your Victron dealer.

smallBMS NG