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Smart BMS CL 12-100

3. Installation and configuration

In this section:

3.1. Important warning and note


Lithium batteries are expensive and can be damaged due to over discharge or over charge.

The shutdown due to low cell voltage by the BMS should always be used as a last resort to be on the safe side at all times. We recommend not letting it get that far in the first place and instead either shutting down the system automatically after a defined state of charge (this can be done with a BMV whose relay can control the remote on/off port of the BMS via an adjustable SoC value) so that there is always enough reserve capacity in the battery, or to use the remote on/off function of the BMS as a system on/off switch.

Damage due to over discharge can occur if small loads (such as: alarm systems, relays, standby current of certain loads, back current drain of battery chargers or charge regulators) slowly discharge the battery when the system is not in use.

In case of any doubt about possible residual current draw, isolate the battery by opening the battery switch, pulling the battery fuse(s) or disconnecting the battery plus when the system is not in use.

A residual discharge current is especially dangerous if the system has been discharged completely and a low cell voltage shutdown has occurred. After shutdown due to low cell voltage, a capacity reserve of approximately 1Ah per 100Ah battery capacity is left in the battery. The battery will be damaged if the remaining capacity reserve is drawn from the battery, for example, a residual current of just 10mA can damage a 200Ah battery if the system is left discharged for more than 8 days.

Immediate action (recharge the battery) is required if a low cell voltage disconnect has occurred.


Note that Smart BMS CL units manufactured up to and including ba number HQ2109 (check the SN number on the back of the BMS) are powered from the ALTERNATOR/STARTER BAT port. Units made after that will be powered by the Li-ION port.

3.4. Installation

Before installation, make proper system design considerations to avoid unnecessary connections and to keep cable lengths as short as possible. See also the System examples chapter.

  1. Preferably mount the Smart BMS on a vertical surface for optimal cooling.

  2. Determine the rating of Alternator/Starter Bat+ port fuse. The fuse doubles as a shunt, thus the Smart BMS will limit the input current according to the rating of this fuse. For fuse and corresponding current limit please see the table below.

  3. Choosing the right fuse will prevent overheating of the alternator and/or DC cabling.

  4. Disconnect the cabling from the minus pole of the starter battery.

  5. Pull off the remote on/off connector to prevent unwanted switching of the Smart BMS.

  6. Install and connect fuses and all electrical wiring, leaving the negative poles of the lithium batteries and the starter battery disconnected. Connect the starter battery positive to the Alternator/Starter Bat+ terminal and the lithium battery positive to the Li-Ion+ terminal. Make sure the M8 nuts of the fuse are tight (mounting torque: 10 NM).

  7. Daisy chain the battery control cables between the lithium batteries and connect the ends to the BMS port. To extend the communication cables between a Lithium Battery Smart and the BMS, use the M8 circular connector Male/Female 3 pole cable extensions.

  8. Connect the supplied GND cable to the negative of the lithium battery and the starter battery. Note that the supplied GND cable must be protected accordingly. Depending on the application a fuse between 300mA and 1.3A is required. Use the specifications to determine the expected power consumption of the Smart BMS using Load and Charge disconnect and the pre-alarm output. This value multiplied by 1.25 determines the value of the fuse to be used. Example: Current consumption 16mA + Load disconnect output 10mA + Charge disconnect output 10mA + pre-alarm output 1A = 1036mA x 1.25 = 1.3A fuse rating.

  9. Reinsert the remote on/off connector on the Smart BMS. It is mandatory to install either an on/off switch between L and H of the remote on/off terminal or the wire loop (default) for correct operation.

  10. The Smart BMS is now ready for use.

Fuse rating

Max alternator charge current




If the required alternator charge current is less than 40A, please use the supplied ATO fuse holder with an appropriate ATO fuse pair according to the table.







2 x 30A


2 x 20A


2 x 15A


2 x 10A


2 x 7.5A


3.5. Configuration

3.5.1. Smart BMS settings

The Smart BMS is configured via Bluetooth and the VictronConnect app. See the VictronConnect manual for download and installation details. The following steps describe the configuration process and options:

  1. Power up the Smart BMS according to the Installation chapter.

  2. Open VictronConnect. The Smart BMS will appear on the Device list either under My devices or Other devices (the latter when connecting for the first time).

  3. Tap on the Smart BMS. The pairing dialogue will start (default PIN code is 000000).

  4. Once connected, the Battery status page is displayed, showing the lithium battery voltage, the soft switch state, Alternator/Starter voltage and alternator charge current percentage, followed by BMS status messages. When connecting for the first time, a pop-up message appears asking you to set the fuse type in the Settings menu to also be able to see the charge current (in percentage).

  5. Tap the cog wheel in the top right to open the Settings menu and set the following:

    1. Fuse type:

      Set the correct fuse type rating as explained in the Installation chapter. Make sure it matches with the physically installed fuse.

    2. Battery Pre-alarm usage:

      In case of a lithium battery without pre-alarm feature, change the Battery Pre-alarm usage to 'Pre-alarm not available', otherwise leave the default setting 'Use pre-alarm'.

    3. Pre-alarm:

      Choose between continuous and intermittent pre-alarm.

    4. Battery charge limit:

      Set the Battery charge limit (range: 13.0V..15.3V) to a value at which charging should be deactivated. Normally this value should be 14.2V for a Victron Lithium Battery Smart. As soon as this value is reached, charging of the battery is interrupted via the Alternator/Starter Batt+ and System+ inputs. The inputs will turn on again when the battery voltage is 0.5V below the battery charge limit for 10 (consecutive) seconds.

    5. Remote on/off function:

      This setting defines what is controlled by the Remote on/off terminals. The default is that it only disables the Alternator.

      Options are:

      Disable alternator: Disable charging via the Alternator port. The BMS functionality is retained.

      Switch everything off: Everything, including the BMS functions, is switched off. This option is suitable as an on/off switch for the system. Note that the BMS continues to consume energy from the battery to maintain the remote control function, albeit less than 0.01W. But this adds up over time and can completely drain the battery in the long run. Therefore, make sure that the battery is completely disconnected from the system if you leave it to its own for a longer period of time.

  6. The configuration of the Smart BMS is now complete and the status is displayed. Depending on the system status, additional information is shown.

3.5.2. VictronConnect status display