SOK Warranty Issue

[MattFR]

In 2022 I purchased 4 rack mount 48V SOK batteries from SOK Europe (I'm in the UK).. They never charged properly from the start. The problem turns out to be the BMSs are not balancing the cells and go into over voltage protection before the battery is fully charged. SOK Europe have been unable to update the BMS firmware remotely and I've tried manually balancing, but to no avail. The upshot is that SOK Europe refuse to honour their stated warranty and return the batteries for repair. The best they are offering me is one new BMS for me to replace myself. They've even resorted to calling me a liar, despite seeing all the batteries' data and attempting unsuccessfully to fix remotely. I believe there is no SOK in Europe and that they are operating from China, so I have no legal way to get them to play ball.. My question is do you have any contact details for SOK headquarters in Canada? I can't track them down. I believe if I could talk to them they would be reasonable and resolve my issue.


Thanks for you attention.

Matthew

 

[HighTechLab]

There is no SOK headquarters in Canada; merely a warehouse where they were selling batteries like in Europe. In the USA, I am the exclusive distributor for the SOK 48v battery, and work to resolve these issues on my side and stand behind what I sell to avoid these kind of problems.

related thread: https://diysolarforum.com/threads/sok-48v-an-honest-review-in-2-stories.62611

 

[MattFR]

Thanks for the reply. I obviously made a big mistake, believing that there was a proper European distributor and a Canadian parent company. I see others have experienced the no warranty, warranty from them too. Now I have £000s of junk hardware.....

 

[marionw]

You might try using the SOKTools.exe software to monitor your batteries as they charge.
This software will allow you to to view cell voltages for each battery as well as any alarm or protection faults. You will also be able to monitor if/when cells are being balanced.

You may need to adjust the charge voltage to prevent any cell from exceeding the Cell Over Voltage Protection setpoint (most likely 3.60 and can be viewed on the "Parameter Setting" tab). If your batteries have never been properly charged or conditioned before placing into service it is most likely you have a "runner" cell, one that charges much faster than the other and reaches Cell Over Voltage Protection which results in the BMS stopping further charging. Simply control the charge voltage to prevent this.
For example
3.5 volts per cell x 16 cells = 56 volts.
3.45 volts per cell X 16 cells = 55.2 volts.
Start with the charge voltage set to 55.2 and allow the battery to charge, once current reduces to near zero slowly increase the charge voltage while preventing any cell from exceeding 3.55 volts.

If you are using your inverter for the charging source you may have to change the Battery Type to USER (or something that allows you to set the charging voltage). In addition if you have grid input to your inverter it is oftentimes easier to control the charge by setting the inverter to pull power from the grid rather than the PV array.

Install the software and connect the RS232 to USB cable to the RS232 jack (small RJ12 jack) on the "Master" battery.

In the upper right of the "Realtime Monitoring" tab, in the "Serial Port" box, select FF for the "Pack" address before you open the serial port. Then all you have to do is select the numbered button at the top for the battery you want to view.

You will need an RS232 to USB cable: This is the one I use:

Amazon.com

Download the SOKTools.exe software. Use the link at the bottom of the page "SOK Tools 2023 version (Includes monitoring and protocol edit)"

SK48V100 Server Rack Battery Owner & Operator's Manual

Full instruction manual for the SOK SK48V100 server rack battery. Everything you need to know is contained within this document!

www.currentconnected.com

 

[HighTechLab]

If bought the batteries in 2022, there is an older version of the software on the same page, that one is going to be the one that is compatible with this hardware version.

If SOK can send you a new BMS, that would be helpful, the 2023+ versions with the latest firmware are a lot better than the 2022 versions.

 

[42OhmsPA]

I've tried manually balancing, but to no avail.

What steps did you take?

 

[MattFR]

Thanks Dexter. SOK are sending one new BMS supposedly of the latest iteration. That means I may have one working battery out of 4.

You might try using the SOKTools.exe software to monitor your batteries as they charge.
This software will allow you to to view cell voltages for each battery as well as any alarm or protection faults. You will also be able to monitor if/when cells are being balanced.

You may need to adjust the charge voltage to prevent any cell from exceeding the Cell Over Voltage Protection setpoint (most likely 3.60 and can be viewed on the "Parameter Setting" tab). If your batteries have never been properly charged or conditioned before placing into service it is most likely you have a "runner" cell, one that charges much faster than the other and reaches Cell Over Voltage Protection which results in the BMS stopping further charging. Simply control the charge voltage to prevent this.
For example
3.5 volts per cell x 16 cells = 56 volts.
3.45 volts per cell X 16 cells = 55.2 volts.
Start with the charge voltage set to 55.2 and allow the battery to charge, once current reduces to near zero slowly increase the charge voltage while preventing any cell from exceeding 3.55 volts.

If you are using your inverter for the charging source you may have to change the Battery Type to USER (or something that allows you to set the charging voltage). In addition if you have grid input to your inverter it is oftentimes easier to control the charge by setting the inverter to pull power from the grid rather than the PV array.

Install the software and connect the RS232 to USB cable to the RS232 jack (small RJ12 jack) on the "Master" battery.

In the upper right of the "Realtime Monitoring" tab, in the "Serial Port" box, select FF for the "Pack" address before you open the serial port. Then all you have to do is select the numbered button at the top for the battery you want to view.

You will need an RS232 to USB cable: This is the one I use:

Amazon.com

Download the SOKTools.exe software. Use the link at the bottom of the page "SOK Tools 2023 version (Includes monitoring and protocol edit)"

SK48V100 Server Rack Battery Owner & Operator's Manual

Full instruction manual for the SOK SK48V100 server rack battery. Everything you need to know is contained within this document!

www.currentconnected.com

You might try using the SOKTools.exe software to monitor your batteries as they charge.
This software will allow you to to view cell voltages for each battery as well as any alarm or protection faults. You will also be able to monitor if/when cells are being balanced.

You may need to adjust the charge voltage to prevent any cell from exceeding the Cell Over Voltage Protection setpoint (most likely 3.60 and can be viewed on the "Parameter Setting" tab). If your batteries have never been properly charged or conditioned before placing into service it is most likely you have a "runner" cell, one that charges much faster than the other and reaches Cell Over Voltage Protection which results in the BMS stopping further charging. Simply control the charge voltage to prevent this.
For example
3.5 volts per cell x 16 cells = 56 volts.
3.45 volts per cell X 16 cells = 55.2 volts.
Start with the charge voltage set to 55.2 and allow the battery to charge, once current reduces to near zero slowly increase the charge voltage while preventing any cell from exceeding 3.55 volts.

If you are using your inverter for the charging source you may have to change the Battery Type to USER (or something that allows you to set the charging voltage). In addition if you have grid input to your inverter it is oftentimes easier to control the charge by setting the inverter to pull power from the grid rather than the PV array.

Install the software and connect the RS232 to USB cable to the RS232 jack (small RJ12 jack) on the "Master" battery.

In the upper right of the "Realtime Monitoring" tab, in the "Serial Port" box, select FF for the "Pack" address before you open the serial port. Then all you have to do is select the numbered button at the top for the battery you want to view.

You will need an RS232 to USB cable: This is the one I use:

Amazon.com

Download the SOKTools.exe software. Use the link at the bottom of the page "SOK Tools 2023 version (Includes monitoring and protocol edit)"

SK48V100 Server Rack Battery Owner & Operator's Manual

Full instruction manual for the SOK SK48V100 server rack battery. Everything you need to know is contained within this document!

www.currentconnected.com

Thanks MarionW. I'll give that a try. I've spent months trying to get help from SOK. They did end up getting me to manually balance the cells and reducing the "runner" cell voltage below the others. The problem was that the next higher cell became the "runner" and the same over voltage cut off happened. They didn't advise on adjusting the charging voltage as you have.

 

[goldserve]

Just wondering how your system is hooked up, what are you charging to and how much current. Are all cells over 3.5V or some cells below 3.4V while the runner hit 3.65?

 

[42OhmsPA]

Reducing the charge voltage will help a lot.
You could also add an active balancer, temporary or permanent.

 

[HighTechLab]

You could also add an active balancer, temporary or permanent.

Please no, active balancers cause far more issues than they fix.

Thanks Dexter. SOK are sending one new BMS supposedly of the latest iteration. That means I may have one working battery out of 4.

The old ones will still work, but you could try and ask them if they will sell you BMSs for the rest, that way you can make them all match.

 

[MattFR]

Reducing the charge voltage will help a lot.
You could also add an active balancer, temporary or permanent.

Excuse my ignorance, but I thought the BMS was supposed to balance the cell voltages? What is the active balancer you suggest? How does it connect to the battery?

 

[MattFR]

Please no, active balancers cause far more issues than they fix.


The old ones will still work, but you could try and ask them if they will sell you BMSs for the rest, that way you can make them all match.

Yes, I could try that. I'll have to have a serious word with myself before I'll be able to pay them to replace the rubbish they first sold me.....

 

[42OhmsPA]

Please no, active balancers cause far more issues than they fix.

Interesting. I haven't heard many people say that and consider you quite knowledgeable in the field.
I don't understand how if they setup to not start balancing until ~3.42V or higher.


Is the SOK 48V user serviceable?
Just break it down and top balance it.

 

[goldserve]

Active balancers use a different technique to balance charge between cells and can do that with 2A, 5A balancing current. Passive balancers in the pace bms may be able to take away charge only from the highest cell at 180mA or so range. You need to go slow and let it do its job over weeks and months.

Most diyers prefer the jk bms due to the active balancer. It really works and I have no issues with unbalanced cells. Sure there are weaker and stronger cells but if all cells can reach over 3.55v, that’s all good in my books.

 

[MattFR]

What I don't understand is that each cell is going to reach max at a different time. If the internal BMS can't balance that charging process out, how will the battery ever charge as it should?

 

[42OhmsPA]

Excuse my ignorance, but I thought the BMS was supposed to balance the cell voltages?

It is, as long and you charge to full on a regular basis and let the BMS work.
What voltage are you charging to?

What is the active balancer you suggest?

It 'quickly' transfers power from one cell to another whereas a passive balancer 'slowly' bleeds off extra power as heat

How does it connect to the battery?

The same was a regular BMS does.

 

[marionw]

See if you can get the SOKTools software setup and get to where you can monitor the battery.
With the software you can temporarily decrease the Balance Threshold Voltage (default for most PACE BMS is 3.5 volts) to 3.45 volts. This will permit the BMS to start balancing at a lower voltage.
In addition adjust the charge voltage to limit the charge current to 10amps or less as displayed in the SOKTools software. Higher charge currents usually result in a larger cell differential voltage at a much quicker rate. By limiting the charge current the cells are more likely to charge at close to the same voltage with a lower differential voltage. Slowly increase the charge voltage to maintain charging current until cells start to balance.
Ideally you will want to get as many cells as possible to charge to at least 3.5 volts which means that once you get as many cells as possible to balance at 3.45 volts you will need to reset the Balance Threshold Voltage back to 3.5 (or whatever the default was)

Note: Once charge current drops the 0.5 amps or less the BMS (and SOKTools) will show zero current. This is just because the BMS is not capable to reporting lower currents.

Patience will pay off and once you get the batteries conditioned you may need to manage the charge once in a while.

The same RS232 to USB cable will work with Solar Assistant and Solar Assistant will display all the batteries an depending on your inverter SA can also monitor the inverter.

SOKTools screenshot with cells that are being balanced.

 

[MattFR]

See if you can get the SOKTools software setup and get to where you can monitor the battery.
With the software you can temporarily decrease the Balance Threshold Voltage (default for most PACE BMS is 3.5 volts) to 3.45 volts. This will permit the BMS to start balancing at a lower voltage.
In addition adjust the charge voltage to limit the charge current to 10amps or less as displayed in the SOKTools software. Higher charge currents usually result in a larger cell differential voltage at a much quicker rate. By limiting the charge current the cells are more likely to charge at close to the same voltage with a lower differential voltage. Slowly increase the charge voltage to maintain charging current until cells start to balance.
Ideally you will want to get as many cells as possible to charge to at least 3.5 volts which means that once you get as many cells as possible to balance at 3.45 volts you will need to reset the Balance Threshold Voltage back to 3.5 (or whatever the default was)

Note: Once charge current drops the 0.5 amps or less the BMS (and SOKTools) will show zero current. This is just because the BMS is not capable to reporting lower currents.

Patience will pay off and once you get the batteries conditioned you may need to manage the charge once in a while.

The same RS232 to USB cable will work with Solar Assistant and Solar Assistant will display all the batteries an depending on your inverter SA can also monitor the inverter.

SOKTools screenshot with cells that are being balanced.
View attachment 269377

Thanks for that. All good for me to have another attempt at getting them balanced. I do have SOK tools and the interface lead, I just haven't been able to get clear information from SOK Europe on how to resolve the issue. I'll let you know how I get on. Cheers.

 

[marionw]

Thanks for that. All good for me to have another attempt at getting them balanced. I do have SOK tools and the interface lead, I just haven't been able to get clear information from SOK Europe on how to resolve the issue. I'll let you know how I get on. Cheers.

The password needed to change entries on the "Parameter Setting" tab is paceadmin

 

[MattFR]

Oh, that is a crucial bit of info. Thanks!