2.1 Managing Settings

This page explains how to handle the whole set of settings of a BMS during commissioning: how to read them, change them and save them, when a change takes effect, what the factory defaults do, and how a settings file serves as a backup and as a copy for other packs. The pages on the individual settings say which value to choose; this page is about moving those values safely.

Applies to

Boards: BMS1820, BMS3610, BCU2002, BMS1601, BMS1810. LiMon™: the latest LiMon™ release.

2.1.1 How It Works

A setting value can be in four places. Most mistakes come from thinking that a value is in one place when it is in another.

  • On the LiMon™ screen. This is what you see and edit on the settings tabs. Nothing changes in the BMS until you save.
  • Stored in the BMS. The stored values stay through a restart and a power loss. Read All Settings shows these values.
  • In use by the BMS (live). After a save, the BMS uses the new values, except for the settings in Table.2.1.1, which it takes only at its next start (2.1.2). For those settings the stored value and the live value differ until the restart, and LiMon™ cannot show you the live one.
  • In a settings file. A file on your PC, made with Export Settings. It changes nothing until you import it and save.

Fig.2.1.1: Settings Workflow

1 Read Read All Settings brings the stored values to LiMon™ 2 Back up Export Settings before you change anything 3 Change edit the values; changed fields turn orange 4 Save Save Changes or Save All Settings; wait a few seconds 5 Restart? a setting that acts after a restart changed, or a CRITICAL event? 6 Check Read All Settings, Live View, Events: as you intended? 7 Export Export Settings again; keep the file with the pack no yes no: correct and save again yes Restart System with no load and no charger current Done pack set up, backup stored The buttons act on the settings of all tabs. Importing a settings file takes the place of step 3; after an import, save with Save All Settings. A CRITICAL event raised during setup, for example by a wrong cell count, stays until a restart.

The seven buttons sit at the bottom of every settings tab and act on the settings of all tabs, not only on the tab you see. The LiMon™ reference names each one: 7.8 Settings Buttons.

Recommended practice

Export a backup before you change anything, export again when commissioning is finished, and keep that file with the documents of the pack.

2.1.2 Reading and Saving

Read All Settings loads every stored value from the BMS into LiMon™. LiMon™ does not do this when it connects, so press it first, every time. The read values are also the reference for the marks on the screen: a field whose value differs from the last read gets an orange border, and the Save Changes button gets one too.

Connecting LiMon™ to the BMS is described in 5. Connection.

  • Save Changes writes only the fields with an orange border. With no changed field it shows "You haven't made any changes." Use it for normal work.
  • Save All Settings writes every setting shown in LiMon™. Use it after an import, so that the BMS holds the whole set. It refuses to run on a screen that has not been read yet, because the empty fields are not valid values.

Both buttons check the ranges first. A value outside its range stops the save with the warning "Some properties are not between in valid range!" and nothing is written. LiMon™ reads every value back as it saves. There is no "saved" message: the loading message disappears and the orange borders clear. If the connection fails, LiMon™ shows "Failed to save settings. Check connection." and stops; the values before that point are already written, so repair the connection, press Read All Settings and save again.

When a saved value takes effect. The BMS stores the values and starts to use them about one second after the last value has arrived. Wait a few seconds before you remove the power from the BMS; values that are not stored yet are lost.

Settings that need a restart. The settings in Table.2.1.1 are taken only when the BMS starts. LiMon™ does not mark them. After a save, Read All Settings already shows the new value while the BMS still works with the old one.

Table.2.1.1: Settings That Need a Restart

Setting LiMon™ tab Until the next start
CANBus CH#1 Speed Interface The BMS stays on the old bus speed.
CANBus CH#1 Protocol Interface The BMS keeps the old protocol.
CANBus CH#1 Data Period Interface The BMS keeps the old period.
CANBus CH#1 Base Frame ID Interface The BMS keeps the old frame IDs.
MODBus No#0 ID Interface The BMS answers on the old address.
Multi Master (MM) Config Interface The Multi-Master communication stays set up for the old role.
Slave Module Type Selection Battery The BMS keeps the old module type and does not find the new modules.
INPUT n Assignment Peripheral The state of the old function can stay in effect, for example a path held OFF (3.10 Inputs and Outputs).

The BMS finds its modules only at start-up, so adding or removing a module needs a restart as well; see 3.1 Battery Topology.

A CRITICAL event during setup needs a restart too. A wrong cell count, for example, raises Cell Connection Error at the first start or after Default Settings. It stays, with both paths OFF, until the next start, even after you correct the value; see 4.1 Protection and Recovery.

Press Restart System with no load and no charger current, because the BMS takes the zero of the current sensor at every start; see 3.6 Current Measurement.

State of charge. Two settings also act on the state of charge when you save them:

  • Initial SoC: a value different from the stored one sets the state of charge to that value at once. Saving the same value changes nothing.
  • Usable Pack Capacity: a new value keeps the state of charge in percent. Set it before Initial SoC.

Licence. With a VIEWER licence the setting fields on the tabs are locked, so values cannot be typed. The seven buttons stay active: Read All Settings, Export Settings and Restart System work, and so do Import Settings, the two save buttons and Default Settings. See 3. Licencing for the licence itself.

2.1.3 Defaults

Default Settings replaces every setting in the BMS with the defaults built into the firmware of that board. LiMon™ first asks for a confirmation. The defaults are a neutral starting point and they are not the values of your battery: the BMS is not ready to run a pack afterwards.

Danger

Default Settings erases all current settings and cannot be undone. Export a backup first.

Table.2.1.2: What Default Settings Gives

Area Result
Battery 7 cells on the first module, other modules off; Usable Pack Capacity 38000 mAh; Initial SoC 50 %
Cell limits Generic values, for example O.V. Protection 4175 mV and U.V. Protection 3050 mV, not chosen for your cells
Balancing Balancing Method: Balance Restricted, so no balancing
Inputs and outputs No function assigned
Current sensor Coefficients 0 and 500; on BMS1601 1600 and 0
Communication CANBus CH#1 Base Frame ID 0xAAA, MODBus No#0 ID 1
  • Lost: every value you set on the settings tabs, the calibration of the current sensor included.
  • Kept: the serial number, the hardware and firmware versions, the cycle count and the event log.
  • After Default Settings: the BMS does not restart by itself and LiMon™ does not refresh the screen. Press Read All Settings, then import your backup or set the values again, and save. Press Restart System after that: the communication settings of Table.2.1.1 take effect, and a Cell Connection Error raised by the default cell count clears. Then check the state of charge.

2.1.4 Backup, Import and Export

Export Settings writes the values shown on the LiMon™ screen to a .libat file on the PC. Import Settings loads such a file back onto the screen. Both need a connected BMS; otherwise LiMon™ shows "Status not found. Please Re-connect a Port."

  • What it writes: the values on the screen, not the stored ones, so a field with an orange border goes into the file with its unsaved value. Press Read All Settings first. Export refuses to run on a screen that has not been read.
  • What the file holds: every setting of every settings tab, including the communication settings and the charging current table.
  • What the file does not hold: the serial number, the versions, the real state of charge, the cycle count and the event log.
  • The file name: LiMon™ proposes Limon-<version>-Settings-<model>-hw<hw>-sw<sw>-<date>-<time>. Keep this part of the name: the model and the versions are written only there, not inside the file.
  • The format: the file is encrypted and cannot be read or edited outside LiMon™.

Import changes only the screen. The BMS stays as it is until you save, and the imported values that differ from the last read get an orange border, so you can look at them before you save. LiMon™ does not check whether the file comes from the same board type. A file that cannot be read gives no message, so if nothing changes on the screen, check the file.

To restore a backup:

  1. Read All Settings, so that LiMon™ holds the values of this BMS.
  2. Import Settings, then look through the fields with an orange border. Check Initial SoC: a value different from the stored one sets the state of charge when you save.
  3. Save All Settings.
  4. Restart System, with no load and no charger current, so that every setting is in use and a CRITICAL event raised before the restore clears.
  5. Read All Settings again and compare.

A file from an older LiMon™ release can lack settings that were added later. Those settings keep the value on the screen, which is one more reason to read before you import.

2.1.5 Copying a Configuration to Another Pack

A file is a quick way to configure several packs that are the same: same board, same cell count, same sensor and same chemistry. Every value is copied, also the values that must differ from pack to pack (Table.2.1.3).

  1. On the finished pack: Read All Settings, Export Settings.
  2. On the new pack: Read All Settings, Export Settings, to keep its own values as a backup.
  3. Import Settings with the file of the finished pack.
  4. Correct the settings of Table.2.1.3 on the screen.
  5. Save All Settings, then Restart System with no load and no charger current.
  6. Calibrate the current sensor of this pack (3.6 Current Measurement).
  7. Read All Settings, check the result, and Export Settings as the file of this pack.

Table.2.1.3: Settings to Check on Every Pack

Setting Why
Current Sensor Ch#1 Coeff. Each sensor has its own tolerance, so the calibrated value of the first pack is only a starting value.
Current Sensor Ch#2 Coeff. As Ch#1.
MODBus No#0 ID Two packs on one RS485 bus cannot share an address.
CANBus CH#1 Base Frame ID Two packs on one CAN bus must not send the same frame IDs.
Multi Master (MM) Config A Multi-Master system has one main controller; the other packs are slaves.
Initial SoC A value different from the stored one sets the state of charge of this pack when you save. Enter the real state of this pack.

2.1.6 Checking the Result

  • After a save: no orange borders are left on the tabs, and Save Changes answers "You haven't made any changes."
  • After Read All Settings: every value is the one you set.
  • After a restart: CAN and Modbus work with the new settings, and Live View shows the expected cell count and state of charge.
  • In Events: no new event that comes from the change.
  • On the PC: the final file exists, and its name shows the right model.

2.1.7 Common Mistakes

  • Values changed but not saved. The orange border stays on the screen and the BMS keeps the old value. Press Save Changes and check that the orange borders clear.
  • Import taken for a save. After Import Settings only the screen has changed. Press Save All Settings.
  • Export before reading. Export refuses to run on an empty screen, and after unsaved edits the file holds values that the BMS does not have. Press Read All Settings first, or save first.
  • Forgetting the restart. After a change of a setting in Table.2.1.1, LiMon™ shows the new value but the bus still works with the old one, for example a charger or an inverter that stays silent. Press Restart System.
  • Restarting with current flowing. The BMS takes the zero of the current sensor at the start, so the reading is shifted until the next clean start. Remove the load and the charger current first.
  • Power removed right after a save. The BMS stores the values about one second after the last one arrives. Wait a few seconds.
  • Importing a file from another board type. LiMon™ accepts it without a warning, and the wrong module setup, limits and input and output functions reach the BMS on the next save. Check the model in the file name before you import.
  • Same file on every pack without corrections. Packs on one bus then answer on the same address or send the same frame IDs, and the current reading of each pack carries the error of another sensor. Work through Table.2.1.3.
  • State of charge jumps after an import. The file holds Initial SoC; a different value sets the state of charge when you save. Enter the real state of the pack before you save.
  • No backup before Default Settings. All values, the calibration included, are gone. If no file exists, the settings have to be entered again from your notes and the current sensor calibrated again.
  • Running the pack on the defaults. The defaults are not chosen for your battery, and no output function is assigned. Set up the pack before you use it.