THUNDERSTRUCK MOTORS BMS VC1 Master Control Unit Instructions
- June 5, 2024
- THUNDERSTRUCK MOTORS
Table of Contents
THUNDERSTRUCK MOTORS BMS VC1 Master Control Unit
Introduction
The Thunderstruck BMS VC1 is a microprocessor-controlled device that reads
cell voltages from one or more Valence™ battery modules and selects an action
based on a comparison between reported cell information and BMS configured
limits. Action options include opening circuits in response to out-of-limit
cell voltages or temperatures, making it possible to control both charge and
load circuits in a battery-powered system. The BMS automatically initiates
module-level cell balancing, but not inter-module balancing (between modules).
This feature is being investigated for a future release.
The BMS provides a simple user interface for setting voltage limits and for
listing connected modules and module cell voltages. Data connectors between
modules in the pack are chained together without concern for parallel/series
orientation. The BMS connects to one end of the chain, and the provided
termination plug connects to the other end.
BMS Setup
PC/Mac Software
To communicate with the BMS, connect it to your computer using the provided
micro USB cable. The BMS will be recognized as a serial device with an
assigned COM port. You can use any serial terminal software to communicate
with the BMS, however, we suggest using a free open source program like Putty
(Windows) or Coolterm (Mac).
The assigned COM port number can be found using the Windows Device Manager and
then entered into Putty. Cool term provides a dropdown to select available
ports on the Mac. See the following document for applicable information about
these two options.
http://www.thunderstruck-
ev.com/images/companies/1/DD_SerialPortUtilities_v1.2.pdf
Android Software
To communicate with the BMS using an Android device you will need to install a
serial terminal app such as this, from Google Play:
https://play.google.com/store/apps/details?id=de.kai_morich.serial_usb_terminal
Connect the BMS to the Android device with an OTG micro USB serial cable. Make
sure that the host end of the cable is connected to the Android. For correct
text alignment, set up the app to use a monospace font.
Wiring Instructions
Build up the pack, attach power interconnects and verify power output, then
connect module plugs between modules until all but the end plugs are
connected. Connect the BMS Termination and BMS Plug (see below) to the end
module connectors. Next, refer to the diagram below and complete the BMS
wiring per the actual system requirements.
Charge and load enable circuits are controlled by relays. If controlling power
circuits, use power contactors rated for charge and load voltage and current.
A DCDC converter from the pack is required if a 12 volt battery or supply is
not available.
Configuration
After the wiring is complete and you are communicating with the BMS, you can
configure the BMS to work with your group of battery modules. If you purchased
your modules along with the BMS, the configuration should be already completed
and locked. If not, then take the following steps to configure your system.
Start by entering the “update” command to show all the modules connected to
the BMS. If all the modules in your system are not shown in the list, then
plug each module individually into the BMS and “update” again. Label each
module using the listed ID. Use the “set mode” command (see “Commands” below)
to change the ID of one module with any duplicate ID. Plug in all the modules
again and enter update” to verify all are present.
Once the modules are verified, enter the “lock” command to save that set of
module IDs. After this step, the HLS and LLS limit switches will be active.
To change the HVC and LVC values, use the “set” command. If changed, also set
the HVCC and LVCC values. Set the HVCC approximately 0.1 volt below the HVC
value, and set the LVCC value 0.1 volt above the LVC value.
High & Low Limit Switches
The BMS has two limit switches that can be used to control other devices. Both
the HLS (High Limit Switch) and the LLS (Low Limit Switch) are open collector
outputs found on many electronic devices. They behave like a normally open
switch that is connected to the ground when activated.
The method for controlling a specific external device depends on features
supported by that device. Many devices have a control/enable input that can be
activated directly by a limit switch from the BMS. If no such options are
available, you can also use a limit switch to trigger a large relay or
contactor, indirectly disconnecting the other device from its power. In most
cases the HLS would be used to control a charger or charge controller and the
LLS would be used to control whatever you are trying to power, such as a motor
controller, AC inverter, LEDs, buzzer, etc.
Commands
The following commands are available in the VC1 – these are not case- sensitive.
- “update” displays a list of connected modules and their ID values
- “show cells” lists the connected set of modules along with module cell voltages
- “show config” shows the list of configuration setting
- “debug” shows a list of errors useful for troubleshooting
- “lock” saves the current pack ID list (required for operation)
- “set” sets parameter values, using “set (parameter) (value)” – Example: “set hvc 3.55”
- “set mod” used to change a module ID. Example: change 3 to 9, enter: “set mod 3 9”
- “enabled” sets LS output logic. Default is closed when enabled. Example: to set HLS open when enabled: “set HLS enabled open” ( “HLS” is case sensitive on early versions)
- “help” lists the command options available to the user
Parameters
- “hvc” (high voltage cutoff) is the high voltage limit at which the BMS will open the HLS
- “lvc” (low voltage cutoff) is the low voltage limit at which the BMS will open the LLS
- “hvcc” (high voltage cutoff clear) is used to buffer cycling of the High limit switch. If a cell reaches HVC during charge, the BMS will shut off the charger, and the cell voltage drops slightly. The charger will turn back on below HVC, and the cycle repeats. Setting the HVCC below the HVC creates a delay to eliminate rapid cycling. The charger turns back on only after the highest cell voltage drops below HVCC.
- “lvcc” (low voltage cutoff clear) works the same as HVCC, but responds to the low end of the cell voltage range. This allows for turning the load back on only after the lowest cell voltage rises above LVCC.
- “tmax” maximum temperature in Centigrade for charge or discharge
- “tmin” minimum temperature in Centigrade for charge or discharge
Terms
- BMS – Battery Management System
- HLS – High Limit Switch
- LLS – Low Limit Switch
- DCDC – DC to DC converter, typically providing 12v power from main pack voltage
- OTG – On The Go (type of USB cable)
- Relay – an electromechanical switch allowing a low power source to control a high power source
- Contactor – a relay used to control high current circuits
Default Settings
The following example shows default voltage configuration settings programmed into the BMS before shipping. These can be changed as needed for specific applications.
- hvc: 3.600
- hvcc: 3.500
- lvc: 3.00
- lvcc: 3.100
- tmax: 50.00c
- tmin: 5.00c
- HLS Enabled State: CLOSED LLS
- Enabled State: CLOSED
Product Variations and Known Issues
Feature variation may be found in different product versions. Please contact
ThunderStruck Motors with any questions about product features.
Customer reports suggest that the VC1 may power cycle LLS and HLS switches
when closing the computer interface during system operation. Testing shows
variable results depending on the specific computer system and interface
software being used. We recommend testing your system for this behavior, and
to avoid user interface operations as indicated to avoid damage to external
power devices. [email protected]
References
- EV.com | New & Used EVs | Electric Cars for Sale
- 📧[email protected]
- Serial USB Terminal - Apps on Google Play