PylonHV

Youda! once again Thanks for the Valuable Information. The Communication between the Inverter and the Main Pylontech BMS via CAN is 100% Normal. Yes the Current can be set through the inverter(but not as low as 0.5A) and Yes when the BMS demands the Inverter does comply and reduces the current as demanded by the Pylon BMS. The strange thing is that the Pylontech BMS charges all the Cells to 100% state of charge and then Balances all the cells to around 3.4V, so it does Not seem to be the Balancing issue. It is during Discharge that some of the Cells in multiple H48050 modules start to lose voltage/charge and by 45% SOC the difference in Voltage reaches high enough that those modules just go Low on Charge up to the Cut off SOC/Voltage, while the others remain at High State of Charge. Up to this point all the Pylontech H48050 batt modules / Packs are only connected to Pylontech BMS SC0500-40 to keep the Warranty Intact. So far all the valuable input from you guys and based on the behavior of Batteries connected to Pylontech BMS, it seems that H48050 modules can Not hold charge and this is a Valid Case to Invoke Warranty. As previously stated the Warranty Route will be followed First and Foremost. Once again thanks for all the valuable knowledge you and other members have shared!

Greetings all! Have a question. Is there any method / command line for Battery View Software to Limit the Charging Current to 0.5A? Thanks

Thanks again for the reply Youda. If by any chance you have information about any resource where they have successfully Re-Balanced cells for Pylon HV Battery system kindly share. Also if an LV Batt. has UnBalanced cells, how would you Balance them? Can that Technique apply to HV Batt.? Youda, you are a resourceful person in the world of Pylontech batteries, if it is not a huge hassle for you, can you kindly ask someone for information regarding balancing the individual Pylon HV H48050 batt. pack. Looking forward to your opinion, Thanks

Greetings Youda! Still in conundrum of Balancing the Cells for individual H48050 Batt Pack. IF a Separate module/brick is charged directly at a low current to 52.5V, how to Balance Individual Cells? Kindly share your knowledge about Adding H48050 batt. packs(once UnBalancing has been created by the BMS with the addition of extra batt. Packs). Your guidance will be highly appreciated.

Thanks for your reply! One thing which is a bit out of ambit here is that if the Pylontech Main BMS and/or the baattery brick BMU balances the voltages across the cells on daily basis during charge and discharge cycle, then why would there be Cells Imbalance? is it something deeper than just the superficial voltages of the cells?

One more thing to ask, Is there any beneficial effect of connecting 2 modules/bricks in parallel to each other (as can be done for Low Voltage Batt.) for Balancing of Cell Voltages? The goal would be to bring all cells to 3.5V Thanks

Thanks again! When you say a very long time for cell voltages to balance, can you define any ball park figure i.e. Days, Month or even a Year? Here again a question comes to mind (having seen the behavior of Pylontech Balancing algorithm), during every charging cycle (if example of individual module is taken) the top end voltages of the cell cross above 3.5V but the bms does not cut off the current till the higher cell reaches 3.6V while the lowest voltage cell also reaches 3.5V, at this point the voltage delta can be 100milliVolts. The balancing is performed afterwards bringing the voltages close to 3.4V. Technically BMS/BMU balances the cells with every charge cycle, however during Discharge the Module which had imbalance at the top are exposed, as these modules drop charge at around 50%. Why doesn't the BMS cuts power to the highest voltage cell while at the same time charging the lower voltage cell to come upto 3.5V? so that 15cells of the module can be balanced at around 3.5V You must be right in assuming that both HV & LV would be similar, therefore you have seen the behavior of LV cells and balancing. It is pertinent to ask you here that if an external Variable Voltage DC power supply is set at 52.5V (3.5V per cell), would it be able to restrict the higher cells to stop taking charge/increase their voltage once they reach 3.5V and at the same time force the lower voltage cells to come upto 3.5V so that all the cells happily live at 3.5V? any ideas?

Thanks Tinbum for the reply, Actually if the main BMS was that efficient, it would balance the individual cells to around 3.5V. If we take the example of individual cells, the problem starts when one of the cells reaches or crosses 3.5V, the BMS continues to supply this cell (instead of cutting it off) while the lagging cell can be at 3.4V. Ideally the BMS should supply the lagging cell to bring it up to the leading cell, instead the cut off for the leading cell is set at 3.6V and that is where the mismatch is created and Top End Balancing is Not Properly Performed by the main BMS or the BMU of the individual module (Not sure which one is it?). Finally the BMS Balances all the cells to around 3.4V, but during discharge the same module which had around 100milliVolt difference at top end will drop the charge. The whole idea of charging individual Module is so that all the cells can settle at 3.5V, how to perform this task safely and efficiently is any one's guess? As you had Access to the Pylontech Manual where they mention to fully charge the Battery, is there any way (published or otherwise) to know exactly what do they Technically Mean by this?

Tinbum thanks for sharing this picture where Pylontech recommends to charge the modules to 100%SOC before connecting. The question here is What is the Best/Safe way to Charge "Single Module" of H48050 High Voltage Batt.? if the module is connected to Trickle Charger/Variable Voltage DC Charger set at 3.5V per cell (52.5V for 15 cells) at a charging current of 0.5Amps, would this method safely bring all the 15 cells to 3.5V? in a simple way if one of the cell reaches the required 3.5V before other cells, would this cell stop taking charge of 0.5A? or would it continue to take charge as there is NO external Active Balancer in this situation? Would this method be good enough to bring all the cells to 3.5V without any cell getting above this voltage, in another way, would this method work to balance out all the 15 cells of the module? Pylontech in their manual have not mentioned or explained how to balance charge individual Batt. Module to 100% state of charge. Kindly elaborate and if possible provide applicable solution Thanks.

Thanks for the reply Youda!

Youda thanks for the reply! Yes each brick has individual RS232 Port, in fact we have connected to the individual H48050 Batt. Module using Console cable, but the brick was connected to the BMS during this time. The earlier pictures of the Modules voltages were from BMS RS232 port. The issue was that if individual Battery Module is removed from the String, then RS232 connection does Not work? or may be we are missing something here? Do you need to be connected to the variable voltage charger for the RS232 port to work on individual Brick? Also the idea is to charge 3 Batt. modules/bricks in a string through the Solar Inverter up to 95%-97% SOC, at this time remove the individual Batt. Module of H48050 and connect to a Variable Voltage DC Power Supply which is set to 52.5VDC with a charging current between 0.5A to 0.75A and wait for all the cells to come up to 3.5V. If we can be successful in bringing 45Cells of the 3 Batt packs to 3.5V each, then we can try to connect again to the inverter and see the results. The only thing bothering here is as How to monitor the cells during this trickle charge? if it is possible for each unit of H48050 to provide cell voltages through Console cable /RS232 withOut BMS in the picture that would make our task much easy. Looking forward to your opinion.

Thanks for the info! Yes you are correct, each module has 15 cells. Can you kindly inform if an external charger is connected to Individual Batt. Module, how to monitor individual Cell Voltage, so that None of the Cells are Charged above 3.5V to 3.6V? Cells can be monitored with Battery View, however that works when a Minimum of 3 Modules are connected. Looking forward,

As the Battery Packs are Under Warranty, therefore they are only Connected to Pylontech BMS to maintain Warranty. The BMS has a Linear Charge Curve and Right at the top of the charging curve is where the Imbalance occurs and the batteries are UnBalanced with cell voltages of 3.5V (vs) 3.4V, thus UnBalancing by more than 100milli Volts. The BMS then Re-Balances all the Packs to around 3.4V and 3.3V with a State of Charge at 100% (50ah), but the modules which were Un-Balanced at the Top and then Re-Balanced by BMS, these are the Same Modules which Drop the Charge at or Below 45% SOC. Is it possible to connect a variable voltage Charger to a Individual Battery Module Directly? and would it take charge? as these are designed differently compared to Low Voltage Batteries. The low voltage ones have their own BMS and Charge level indicators. Solutions would be Highly Appreciated.

That may not be true, as the voltage of new modules is around 50VDC

Thanks for your replies Youda and Tinbum! Can you kindly share different ways to bring all Batt. Modules at the same level? As Youda has correctly pointed out that the system requires a minimum of 3 Batt. Modules to start functioning. Is there any way to Top Balance/Charge 1-Module of Pylontech High Voltage H48050 Separately? Overall state of Health of Battery Pack and Individual Modules is Excellent. Looking forward to your valuable inputs. Thanks