4. Configuration and settings

In this section:

4.1. Configuration of chargers and loads

Before turning on the system, ensure that chargers and loads are correctly configured, particularly their maximum combined charge and combined discharge currents, to avoid exceeding battery limits.

Maximum charge current

The maximum continuous charge current is 1C. The maximum pulse charging current depends on the battery model. Please refer to the Lithium NG battery datasheet for details.

Tip

For optimal battery performance, a charge current of 0.3C is recommended.

Maximum discharge current

The maximum continuous discharge current is 1C. The maximum pulse discharge current is 2C for a maximum of 10 seconds.

Tip

For optimal battery performance, a discharge current of 0.5C is recommended.

Important

Chargers and loads not controlled by the BMS (via ATC and ATD) can permanently damage the battery.

Maximum battery charge- and discharge currents for 12.8V Lithium NG batteries
	12.8/100	12.8/150	12.8/200	12.8/300
Max continuous discharge current	100A	150A	200A	300A
Max pulse discharge current (10s)	200A	300A	400A	600A
Max continuous charge current	100A	150A	200A	300A
Max pulse charge current (10s)	200A	225A	400A	450A

Maximum battery charge- and discharge currents for 25.6V and 51.2V Lithium NG batteries
	25.6/100	25.6/200	25.6/300	51.2/100
Max continuous discharge current	100A	200A	300A	100A
Max pulse discharge current (10s)	200A	400A	600A	200A
Max continuous charge current	100A	200A	300A	100A
Max pulse charge current (10s)	200A	400A	450A	200A

4.2. Power up for the first time

The smallBMS NG switches on when the following conditions are met:

Battery connection: The Bat+ and Bat- terminals of the 7-pin terminal block must be connected to Battery Plus and Battery Minus.
Remote on/off wiring:
- The wire loop must be placed between Remote L and Remote H of the 7-pin terminal block, or
- If a remote on/off switch is used, it must be wired between Remote L and Remote H and switched on.

4.3. smallBMS NG and Lithium NG battery settings

Once powered up, use the VictronConnect app to configure the BMS settings.

Certain parameters such as Battery capacity, Battery voltage, Number of batteries, Number of batteries in series, Number of batteries in parallel are automatically configured and cannot be changed, but they should still be verified for accuracy.

Battery monitor settings:

Unlike other battery monitors, the smallBMS NG has mostly fixed settings that cannot be customised. This is because the smallBMS NG is designed to work exclusively with Victron Lithium NG batteries, where many parameters are predefined based on battery type.

Charged voltage: The voltage above which the battery monitor synchronises and resets SoC to 100%, provided tail current and charged detection time conditions are met.
Tail current: The current below which the battery monitor synchronises and resets SoC to 100%, provided charged voltage and charge detection time conditions are met. Default: 4%, adjustable if needed.
Charged detection time: The duration charged voltage and tail current must be met for SoC synchronisation. Default: 3 minutes, adjustable if needed.
Low SoC warning level: The level at which a warning is issued before the discharge floor has been reached.
The pre-alarm output is activated and a warning is displayed in VictronConnect when the warning is active.
Discharge floor: This parameter has two functions:
- Its primary use is to set the minimum SoC to determine how far the battery may be discharged and to ensure that there is enough energy left for self-discharge after the battery is no longer allowed to discharge (Allowed to discharge = No).
  A restricted depth of discharge extends battery life and provides backup power, e.g., for solar systems until sunrise.
  When the discharge floor is reached, a low SoC alarm is triggered, and ATC is disabled.
  Setting the discharge floor to zero (not recommended) disables this feature.
  Caution
  The discharge floor prevents full discharge and should be set to retain enough energy for self-discharge until recharging is possible.
- It determines the ‘Time remaining’ value in the VictronConnect app, calculated based on the actual discharge current and the set discharge floor.
State of charge: Manually set the current state of charge.
Synchronise SoC to 100%: Manually synchronise SoC to 100%.

4.4. Update BMS and Battery firmware

Firmware updates for the BMS and Lithium NG battery are performed via the VictronConnect app.

General notes on firmware updates

Newer isn’t always better – only update if necessary.
If it works, don’t break it – avoid unnecessary updates.
Read the changelog first – available on Victron Professional.

Use this feature with care. Our main advice is not to update a running system unless problems occur or before the first startup.

Notes on updating the smallBMS NG and Lithium NG battery firmware

The firmware update does not cause a full system shutdown.
During the update, the Charge disconnect output opens, preventing battery charging.
If the update fails, the Load disconnect output will open after 120 seconds as a safety measure, allowing time to retry the update.

Updating the firmware via VictronConnect

Please note the following before performing a firmware update via VictronConnect:

Before updating, refer to the firmware update chapter in the VictronConnect manual for detailed instructions.
If a newer firmware version is available, VictronConnect (ensure it’s up to date) will notify you upon connecting to the BMS.

smallBMS NG