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RT-BMS Summary of Technical Information and FAQ
Check the updated document with the summary of the technical information, sepcification and FAQ for the RT-BMS system.
http://www.ev-power.eu/docs/pdf/GWL/GWL-RT-BMS-TECH-EN.pdf
The RT-BMS pricing is here:http://www.ev-power.eu/RT-BMS-System/

RT-BMS Summary of Technical Information and FAQ

Check the updated document with the summary of the technical information, sepcification and FAQ for the RT-BMS system.

http://www.ev-power.eu/docs/pdf/GWL/GWL-RT-BMS-TECH-EN.pdf

The RT-BMS pricing is here:
http://www.ev-power.eu/RT-BMS-System/

RT-BMS cooler installation
The photo shows the design of aluminum cooling plate to install the RT-BMS high power modules on top of the 200AH cells

RT-BMS cooler installation

The photo shows the design of aluminum cooling plate to install the RT-BMS high power modules on top of the 200AH cells

The update of the specification files for the RT-BMS system
Check the latest version of the RT-BMS documents bellow:
Check the RT-BMS Support documents:http://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-A.pdfhttp://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-B.pdfhttp://www.ev-power.eu/docs/GWL-Power-RT-BMS-Info-C.pdfhttp://www.ev-power.eu/docs/GWL-Power-RT-BMS-parametersEN-D.pdf
GWL Power blog pages:http://gwl-power.tumblr.com/tagged/RTBMShttp://gwl-power.tumblr.com/tagged/RTBMS/page/2   (and more pages)
FAQ: RT-BMS power-on and settings after STAND-BY
Question: At the general power on (+12V) all the contactors are connected for short time. Is it a normal operation? 
Answer: Yes, this is a safety checkup of all contactors and signal lights. This is to confirm that all of these outputs are working properly.
This logic is the same in your car:  when you turn on the starting key in your car,  all important signal lights on the dash board will light briefly to confirm that the signalization is OK (like airbags, EPS, motor oil and other lights)
Question: After the power-on, the unit performs a sort of scan of the system. The numbers of 01.00 to 01.63 (02.00 to 02.63, and 03.00 to 03.63) was displayed. This behavior is also present if we set a number of 4 cells on the system. Is it a normal behavior?
Answer: Yes, this is normal. After power-on the Master unit scans all possible combination (3x 64) to locate any CBU on the data line bus. This is for safety reason to confirm that the communication with all CBU is regular. Also it can help to locate any CBU that would be miss-addressed.
In regular operation the RT-BMS Master should be powered all the time and only to be turned-on/off by means of the stand-by mode.
This logic is like your TV with DVB-T tuner:  you plug the TV on the socket for the first time and it will scan all possible channels.  Following that you keep the TV always ON, and you only use the STAND-BY mode (but it is powered 365 days/24hrs).  Of cause if you disconnect the TV from the main power, and re-connect, it will scan all the channels again.
Question: After the power-on, the system always activates the load contactors (PO1) and  the charging contactors (PO3 and PO4). Why is this so?
Answer: This is a correct function. The contactors are turned on by the setting values of the RT-BMS.  When you power-on the BMS-System and the cells are at regular voltage level, the RT-BMS will check the voltage levels and if the voltage levels are OK, it will turn on the contactors.  When the cells are at 3.3V, you can either discharge them or charge them. That is why all contactors are ON.
The charging contactors will disconnect only when the voltage increase above the levels set in the management software. They will re-connect when the voltage drops down again. Or they will reconnect after the power-on.

FAQ: RT-BMS power-on and settings after STAND-BY

Question: At the general power on (+12V) all the contactors are connected for short time. Is it a normal operation?

Answer: Yes, this is a safety checkup of all contactors and signal lights. This is to confirm that all of these outputs are working properly.

This logic is the same in your car:  when you turn on the starting key in your car,  all important signal lights on the dash board will light briefly to confirm that the signalization is OK (like airbags, EPS, motor oil and other lights)

Question: After the power-on, the unit performs a sort of scan of the system. The numbers of 01.00 to 01.63 (02.00 to 02.63, and 03.00 to 03.63) was displayed. This behavior is also present if we set a number of 4 cells on the system. Is it a normal behavior?

Answer: Yes, this is normal. After power-on the Master unit scans all possible combination (3x 64) to locate any CBU on the data line bus. This is for safety reason to confirm that the communication with all CBU is regular. Also it can help to locate any CBU that would be miss-addressed.

In regular operation the RT-BMS Master should be powered all the time and only to be turned-on/off by means of the stand-by mode.

This logic is like your TV with DVB-T tuner:  you plug the TV on the socket for the first time and it will scan all possible channels.  Following that you keep the TV always ON, and you only use the STAND-BY mode (but it is powered 365 days/24hrs).  Of cause if you disconnect the TV from the main power, and re-connect, it will scan all the channels again.

Question: After the power-on, the system always activates the load contactors (PO1) and  the charging contactors (PO3 and PO4). Why is this so?

Answer: This is a correct function. The contactors are turned on by the setting values of the RT-BMS.  When you power-on the BMS-System and the cells are at regular voltage level, the RT-BMS will check the voltage levels and if the voltage levels are OK, it will turn on the contactors.  When the cells are at 3.3V, you can either discharge them or charge them. That is why all contactors are ON.

The charging contactors will disconnect only when the voltage increase above the levels set in the management software. They will re-connect when the voltage drops down again. Or they will reconnect after the power-on.

FAQ:  Balancing, overcharging and over heating of the CBU modules
Question: I have the RT-BMS installed on 16 cells. It seems to work OK. Only the balancing does not seem to be working properly. The voltage on some of the cells goes up to 4.00V and the CBU does not seem to control this.  The BMS will switch off the charger for some time, but the cells are not fully charged.
Answer: Please note that the balancing current of the CBU is maximal 5A for the standard version and maximal 10A for the high-power version. This means following: if the charging current is higher than 5A (or higher than 10A) the CBU cannot balance the cells and the voltage will increase. When the voltage goes high, the BMS Master unit will first signal to reduce the current (BMS pin B6 – High/LOW). If the voltage of the cells continues to grow, it will signal the full stop of charging (BMS pin B5 – Charging MAIN).   The charging current needs to be reduced bellow the balancing currents of the CBUs to allow for the balancing of the cells without voltage increase.
Keep in mind that the long time balancing is not good for the operation of the cells. Check the details in this article. We always suggest to balance the cells individually before assembling the pack.
The balancing current of the CBUs (5A or 10A) is reached only when proper cooling of the CBUs is provided. If the cooling of the CBUs is poor, the balancing currents will be reduced automatically to avoid over heating.
Question: The RED color LED on the CBU module is blinking during the final stage of the charging. What does it mean?  
Answer: The red color LED signals that the CBU is overheating. You need to improve the cooling of the CBU to allow for the CBU to cool-down to allow the release of the heat.  See also here.

FAQ:  Balancing, overcharging and over heating of the CBU modules

Question: I have the RT-BMS installed on 16 cells. It seems to work OK. Only the balancing does not seem to be working properly. The voltage on some of the cells goes up to 4.00V and the CBU does not seem to control this.  The BMS will switch off the charger for some time, but the cells are not fully charged.

Answer: Please note that the balancing current of the CBU is maximal 5A for the standard version and maximal 10A for the high-power version. This means following: if the charging current is higher than 5A (or higher than 10A) the CBU cannot balance the cells and the voltage will increase. When the voltage goes high, the BMS Master unit will first signal to reduce the current (BMS pin B6 – High/LOW). If the voltage of the cells continues to grow, it will signal the full stop of charging (BMS pin B5 – Charging MAIN).   The charging current needs to be reduced bellow the balancing currents of the CBUs to allow for the balancing of the cells without voltage increase.

Keep in mind that the long time balancing is not good for the operation of the cells. Check the details in this article. We always suggest to balance the cells individually before assembling the pack.

The balancing current of the CBUs (5A or 10A) is reached only when proper cooling of the CBUs is provided. If the cooling of the CBUs is poor, the balancing currents will be reduced automatically to avoid over heating.

Question: The RED color LED on the CBU module is blinking during the final stage of the charging. What does it mean?  

Answer: The red color LED signals that the CBU is overheating. You need to improve the cooling of the CBU to allow for the CBU to cool-down to allow the release of the heat.  See also here.

FAQ: Upgrading older BMS systems

Question: I purchased the RT-BMS from your company in 2009. I have a friend who purchased the BMS system from you in 2012. It is obvious that there are some key differences in the BMS system. It seems that my system has some bugs and problems.  How to solve these problems?

Answer: First thank you for using the RT-BMS system in your application. However, please understand this point: The BMS you purchased in 2009 was produced more than 3 years ago.  From that time till now, some major hardware (HW) improvements were made in the later HW revisions. Also the software (firmware) inside the units was upgraded significantly.  Even the managing software (for PC) was changed completely.

All this information about these updates was regularly published at our support pages. Special limited offers were provide back then:

We tell you honestly, that your version of the BMS is already outdated, no longer supported and can no longer reflect the improvements that were already done.

Simply, it is like an old IBM with Pentium 5 and Windows 95. It has some bugs and “risks” that cannot be upgraded. You cannot have this kind of PC updated to run Windows 7 and the latest software.

I hope you can understand that if you wish to move ahead and you wish to use the RT-BMS for your projects, you need to move ahead with the hardware as well. You cannot stay just with one “old product” that you purchased in 2009.

Why to install a BMS for a battery pack?

Question: Is it important to have a BMS or SBM installed on the battery pack?

Answer: Simply said: Yes!

It is important to install and to use a protection of the lithium batteries.  The batteries need to be protected against deep discharge and the overcharge of the individual cells.  In general there are many ways to protect the cells or packs of the cells against improper use.  Whatever system is used, the main function of the system is to disconnect the battery from the load to prevent over discharge, or disconnect the battery pack from the charger to avoid over charge. The primary reason for the protection is the relatively high cost of the lithium cells and quite easy way to damage their performance or destroy them completely. In view of the expected lifetime (up to 30 years) and number of cycles (thousands) it is worthy to have a measure of protection installed.

Installing a complete Battery Management System (BMS) is the most advanced way of protecting the cells and the battery pack. At this moment there are about 50+ different BMS systems on the worldwide market. Check these links to the BMS selector and BMS option selector. (There are many other systems not listed on this page, and new BMS systems are being developed and produced by more and more companies.) The BMS monitors the voltage of each cell and based on the voltage of each cell, the BMS sends information to the charger and the discharger to protect the battery.

GWL/Power does not endorse any specific BMS model against others. We let the decision to be made by each customer. Based on our long-term commitment to the customer support, we provide an additional support for the RT-BMS system and the BMS123 system.

The cell protection can be done in a simpler way using the Simple Battery Management Board (SBM) or monitoring equipment like CellLog or Akumon (for 12V packs). To allow for an extra safety, multiple „layers“ of protection are suggested to be installed, especially for application critical installations.

** The overview of related links:

The Simple Battery Management Board (SBM) - a single board solution protect the battery pack
http://gwl-power.tumblr.com/tagged/SBM

The Real-time BMS (RT-BMS) system – a complete BMS with multiple functions and ballancing currents up to 10 Amp
http://gwl-power.tumblr.com/tagged/RTBMS

The BMS123 system – an innovative BMS solution with simple installation directly at the cells. (Commercially availible from Sept. 2012, testing units available now)
http://gwl-power.tumblr.com/tagged/BMS123

The Cell Ballancing Module (CBM) to allow the balancing of single cells
http://gwl-power.tumblr.com/tagged/CBM

The CellLog and PowerLog tools to monitor the cells in small installations
http://gwl-power.tumblr.com/tagged/CellLog
http://gwl-power.tumblr.com/tagged/PowerLog

The Akumon – battery monitoring and balancing board for 12V packs.
http://gwl-power.tumblr.com/tagged/Akumon

** Check following FAQ published previously:

The Specifications of the Aluminium Coolers (Heat Sinks)

The attached images shows the sizes and the profile shapes of the heat sink models A75M, ZH-7504, ZH-7505.

Check our offer of the Aluminium Coolers (Heat Sinks) 

RT-BMS Coolers (Heat Sinks) for the CBU modules

We have enlarged the offer for RT-BMS system with high-quality heat sinks. These are designed to be used with the CBU units to allow proper cooling during the balancing. We offer 3 models (sizes and profiles A75M, ZH-7504, ZH-7505)

Check our offer of the Aluminium Coolers (Heat Sinks)

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.

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 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:
Battery deeply discharged – what to do?
Battery charging information - summary of FAQ

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: