SOK Battery report - all good!

[KevinC_63559]

Bought a rack of SOK batteries from Current Connected last June and by mid July had MP-II charge controllers regulating them via the SOK to Victron Can-Bus cable.

(Side note: Any BMS control cable needs to be on a dedicated Can bus port if your using Victron Cerbos)

When first hooked up I routinely received High Voltage alerts. I was assured these would fade away over time. At the end of July, I also purchased the SOK monitoring cable for their BMS application so that I could look at individual cells easily. Back then each pack varied a lot between cells, like upwards of 0.150 volts between cells. That continued until I started putting some loads on the cells. By early August, the variation had dropped to a max of 0.010 volts. Nice to see.

Just checked and four out of five have cells balanced withing 0.002 volts, one outlier at 0.039 volts. That pack has always been an outlier for reasons unknown, perhaps one less-than-ideal cell?

Pack voltage also leveled out over time, originally being as much as 1.5 volts difference. That is now 0.02 volts, with four out of five dead on at 53.02 volts and one at 53.04 volts (unexpectedly not the outlier pack).

I am a bit concerned about the voltage being a bit low, since Absorption is set to 57.6 volts and Float is set at 55.2 volts.

Otherwise very happy with the system.

Any thoughts on the low voltage? @HighTechLab ?

 

[Haze]

I have a question, how are you charging to 57.6 .when hooked up to Cerbo ?

My SOK limit charge to 56v if I’m running them hooked up to my Cerbo. If I run them not hooked up to the Cerbo then they charge to 57.6.

 

[KevinC_63559]

I have a question, how are you charging to 57.6 .when hooked up to Cerbo ?

My SOK limit charge to 56v if I’m running them hooked up to my Cerbo. If I run them not hooked up to the Cerbo then they charge to 57.6.

I'm not... I'm only getting to 53.04 volts max. I have manually configured the MP-II 48/3000 to 57.6V absorption and 55.2 float. Thus my question. Not aware of any Cerbo GX settings to control that but will go look now.

... ok, everything on the Cerbo indicates the Pylontech BMS is in control. So time to see what I can find there.

 

[Haze]

I'm not... I'm only getting to 53.04 volts max. I have manually configured the MP-II 48/3000 to 57.6V absorption and 55.2 float. Thus my question. Not aware of any Cerbo GX settings to control that but will go look now.

Ok, on the cerbo when running closed loop you can program up to 56 V. The Batteries BMS limits what it will allow us to do. I have mine set to 55.2 at the moment.

 

[KevinC_63559]

Ok, on the cerbo when running closed loop you can program up to 56 V. The Batteries BMS limits what it will allow us to do. I have mine set to 55.2 at the moment.View attachment 235783

Ah, figured if I left "limit" unclicked it wouldn't be limited. At least with Cerbo firmware 3.41 you can set that to 57.6, which I just did. Will be interesting to see if that changes anything. Thanks for the feedback!

ps. I'm also running closed loop.

 

[Haze]

I can go above 56v on my Cerbo but the battery limits what it will actually charge to when running closed loop at 56v. Now if I go open loop the battery will charge all the way to 57.6 but I have no control of it, so I keep it closed loop and just charge up to 55.2.

 

[timselectric]

Yes, this is what closed loop communication means.
The BMS is in control of the charging.

 

[Haze]

Yes, this is what closed loop communication means.
The BMS is in control of the charging.

What’s odd is closed loop the battery limits us to 56 and open loop the battery allows 57.6 .

 

[KevinC_63559]

I'll give it few days now that I have the Cerbo set to 57.6 and will report back.

 

[KevinC_63559]

Its creeping up slowly. Part of that is my fault, I had the input current limited low enough my batteries where not fully charging. Fixed that, and now seeing 55.3 volts (a bit over float) until a load is placed on them.

All is well.

 

[timselectric]

What’s odd is closed loop the battery limits us to 56 and open loop the battery allows 57.6 .

In closed loop communications, the battery BMS is in control.
In open loop, it's just along for the ride.

 

[Gojay]

What’s odd is closed loop the battery limits us to 56 and open loop the battery allows 57.6 .

In close loop the BMS is limiting to 56V because that is what the "Pack FullCharge Voltage" is defaulted too. If you change the parameters to 57.6 then it will charge to 57.6.

Use PBMSTools to verify your settings.

 

[Haze]

In close loop the BMS is limiting to 56V because that is what the "Pack FullCharge Voltage" is defaulted too. If you change the parameters to 57.6 then it will charge to 57.6.

Use PBMSTools to verify your

SOK doesn’t allow you to change its BMS settings.

 

[marionw]

SOK doesn’t allow you to change its BMS settings.

Actually you might be able to.

Download the SOKTools.exe software from Current Connected.

Fire up the software, select the correct "Port" and "Pack" address then click the "Open" button to start monitoring the battery.
Enter paceadmin for the password in the "Password" box. If you entered the correct password the background color of the box will change to green.

Select the "Parameter Settings" tab and click the "Read All" button which should populate all the controls with the current settings.
Look at the "Pack FullCharge Voltage(V)" setting.

Modify at your own risk. Changing parameters may invalidate any warranty and/or damage the battery/BMS

Download the software. Last link on the page

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

 

[Gojay]

SOK doesn’t allow you to change its BMS settings.

You need the password. Contact the vendor and get it from them.