RT-BMS Master unit for 192 cells
The photo shows the RT-BMS Mater unit for up to 192 cells. This version of the main unit has all connectors available and supports the CAN bus as well.
Be sure to check the RT-BMS specification to understand the key functions of the system.
High Power CBU modules - detailed photos
The installation of the high-power CBU modules is indentical with the standard CBU modules. They can be replaced directly if high balancing power is needed.
Each RT-BMS data-line must be terminated with the CBUX module (terminal). If needed to have the data-line detachable, it is posible to use the dual connector module.
Check the RT-BMS Support documents:
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-A.pdf
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-B.pdf
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-C.pdf
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-parametersEN-D.pdf
GWL Power blog pages:
http://gwl-power.tumblr.com/tagged/RTBMS
http://gwl-power.tumblr.com/tagged/RTBMS/page/2 (and more pages)
RT-BMS Cell Ballancing Units with DUAL POWER - up to 10A
We are now offering the RT-BMS Cell Ballancing Units (CBUs) with dual power MOFSET transistors that allow the ballancing current up to 10A. The sucess of the balancing function is dependent on proper cooling of the high-power transistors. These must be mounted onto a sufficiant cooler.
Check the RT-BMS offer at EV-POWER.EU
Note: it is not possible to combine the standard CBUs with the high-power CBUs in one set. Your installation can have either standard or the high-power models.
RT-BMS Connection to the TC Chargers
The diagram shows the interconnection of the TC chargers and RT-BMS Master control unit. Color of wires and codes is shown in the table below on the diagram.
RT-BMS Monitor Screen Demonstration
Check the RT-BMS Monitor documentation on-line.
See the product placing at GWL Power on-line web shop.
(The acually available information may differ, based on the software functions)
Question: My mistake I discharged my battery pack very low voltage and the cells are misbalanced. I think the RT-BMS system does not work properly. What shall I do?
Deep discharge: please avoid the deep discharge of the battery pack at any case. You need to monitor the battery pack continually to protect against such deep discharge. You should stop using the pack when the voltage gets too low. You should disconnect the pack from the load in case the pack will be left unattended for a longer period of time. You should never operate the equipment with no supervision.
RT-BMS operation: the RT-BMS system CBU modules measuring input is powered from the cell voltage. If the voltage of the cell drops too low, the CBU unit does not work properly. See the BMS instruction document, page 2: „Operating voltage of the measured cell min 1.8V. max 5.0 V“. In fact the BMS units (CBU modules) may not work reliably under 2.0V! The CBU will stop working with 1.8V and less. The BMS cannot report correct values for these under-voltage cells.
Restoration of the battery pack: you need to charge the cells one by one slowly, to restore the capacity and to get the battery pack balanced again. Check the instruction about:
RT-BMS Monitor unit released - product and manual information
RT-BMS data monitor unit with a touch display (for RT-BMS Master unit). Designed to read and display data from all software versions of RT-BMS Master unit starting from HW version 2.0. The BMS Master Unit is connected to the board using a special I2C to RS232 cable.
In addition to the display of the data, the monitor can be configured to save gathered data from the BMS to a CSV file to be downloaded to your PC.
Check the RT-BMS Monitor documentation on-line.
See the product placing at GWL Power on-line web shop.
RT-BMS Manuals and the CAN connector (L) pin change
A quick overview of the RT-BMS product support documents:
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-A.pdf
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-B.pdf
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-C.pdf
http://www.ev-power.eu/docs/GWL-Power-RT-BMS-parametersEN-D.pdf
Also see the information related to the CAN bus:
http://gwl-power.tumblr.com/tagged/CANbus
The video of the installation of the RT-BMS components
Check the instructive video to see the components of the RT-BMS system and their installation step by step. Check the pricing of the RT-BMS components on-line.
A BMS-Master with heavily burnt components
… well, we all learn by mistakes. Such mistakes however are not covered under the manufacturer’s warranty for the product’s performance and specifications.
FAQ: CAN Bus equipment operation
Question: I have a BMS with CAN option. I have a battery charger with CAN connector, I also have a dash board (display unit) with CAN option. How can I make these components work together over the CAN bus?
Answer: In most cases you need a master CAN bus unit to make the equipment work together. Most of the CAN bus equipment is only either sending data (Read Only mode) or receiving commands (Write Only mode). This equipment has no additional logic to make decisions of operation for other equipment or to control it. The logic of the operation must be set by the master CAN bus unit.
Example: BMS system is sending data (about the status of the battery pack). A ventilator with CAN input is only receiving data (turn on/off and the rotation speed). The BMS itself cannot manage the ventilator. There must be the CAN BUS master unit to process the data from the BMS over CAN and to decide if the temperature is over the limit and when the ventilator is to begin the operation. Then the CAN bus master unit i will send data to the ventilator over the CAN bus.
GWL Tech Report - Long time balancing – a slow way to damage the lithium (LiFePO4) cells
Lithium cell can be destroyed by over charge. The damage by the slow overcharge at balancing level is the most common reason of a gradual damage to the lithium cells. Please study the GWL Technology Report to learn bore about this kind of slow overcharge. The document also gives a practical advice by means of several tips to avoid the damage to the cells by changing the way of cell balancing.
FAQ: I have assembled a new battery pack. I have a BMS that balances with 2A of heat discharge on each cell. I keep charging my cells for many hours already and some cells are already full and some cells are not charged yet. What is the problem?
Answer: Please follow the lithium battery operation instructions closely: the cells must be charged individually to full voltage level (typically 4.0V) before assembling the battery pack. This way the cells will be fully charged and balanced before the first use of the battery pack and there will be no need to balance the cells using the BMS with balancing. (Additionally to the first installation, we recommend to checking the cells of the battery pack from time to time and making the full balancing of all the cells, by means of the individual charging.)
Note: Concerning the balancing using the heat dissipation (over the BMS modules): keep in mind that it takes a lot of time to balance the cells this way. If you have 300Ah cells with +/- 20% misbalance, you need to balance up to 40 Ah of capacity. With 2 A balancing current, you may need 20 hours to finish the balancing. Even more, you waste a lot of energy that will be discharged at the cells that are already fully balanced. That is why we do not recommend to balance the cells this way.
FAQ: RT-BMS connection to chargers - the wiring of the pins
Please note that there is not any standard of the pins used at the charges to communicate with the BMS. As seen from the two photos, there may be completely different wiring on different chargers. (Even on the same type of chargers but from different production time). You always need to check against the information on the sticker at the connector. (Note: if the sticker was lost or removed, there is no way to confirm the wiring.)
FAQ: What type is the connector used at the charger to connect to BMS?
There is usually the Phoenix or WAGO type connector. (Wago 231-104-031-000). Take note that this connector is not designed for frequent manipulations. We suggest you can use other type of connectors that are designed for long life-time.
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