UK Using 3 Fogstar 5.12kWh Energy Server Rack Batteries, cant keep them in sync

[houseofancients]

My 3 batteries were full charged by 2pm today.
Bat1 was 6.81A 55.795V pack volts 100% and balancing,
Bat2 was 6.40A 54.529V pack volts 100% no balancing
Bat3 was 8.29A 54.762V pack volts 100% no balancing.
No alarms and Amps dropped to zero on all after a few mins.
Looks like another sunny day tomorrow so I will see how close together they are then

They are extremely close...
I'd say let them balance out a bit more over the next few days and be done with it

 

[SeaGal]

My 3 batteries were full charged by 2pm today.
Bat1 was 6.81A 55.795V pack volts 100% and balancing,
Bat2 was 6.40A 54.529V pack volts 100% no balancing
Bat3 was 8.29A 54.762V pack volts 100% no balancing.
No alarms and Amps dropped to zero on all after a few mins.
Looks like another sunny day tomorrow so I will see how close together they are then

Do you have a historic log of cell voltage to show the voltage immediately before the BMS decides the pack is at 100%? I would expect that to be around 3.45V - 3.50V per cell (= 55.2 to 56V per pack). Once the BMS reports 100% and the inverter stops providing charge current I would expect the voltage to drop back to 3.35 - 3.40V per cell.

But what puzzles me is how you can have a difference of more than 1.2V between battery packs that are connected in parallel, without any current flow between them. Even if you have resistance in the cabling, there would be current flow and a voltage drop across the cables if the packs are at different voltages. If there is no current flow the voltages should be the same - ohms law dictates that. Have you tried measuring the voltages with a DMM?

 

[Oldman2]

There is a tab on PbmsTools called Multi monitoring but I have no idea how it is set up or how it would work. I can manually take screenshots of realtime monitoring but its pot luck as to the exact moment the BMS thinks its time for 100% and zero inverter charge current.
This was B2 yesterday just before 100%


And B2 at 100%



There is a screen on these batteries and I see currently a snapshot B1 @ 53.994V B2 @ 53.982V B3 53.979V Still charging atm so rising.
My uncalibrated dvm's show 53.6V on all terminals (only goes to 1 decimal place) Next dvm measured B1 @ 54.12V B2 @ 54.11V and B3 @ 54.12V all while charging but you get the idea, there isn't much between them.
I will try again when the batteries are 100% and no charge current.

 

[SeaGal]

Those screenshots look perfectly fine. 3.45V when get to 100% and cells slump back to 3.4V when the charging stops. All cells well balanced.

 

[houseofancients]

Do you have a historic log of cell voltage to show the voltage immediately before the BMS decides the pack is at 100%? I would expect that to be around 3.45V - 3.50V per cell (= 55.2 to 56V per pack). Once the BMS reports 100% and the inverter stops providing charge current I would expect the voltage to drop back to 3.35 - 3.40V per cell.

But what puzzles me is how you can have a difference of more than 1.2V between battery packs that are connected in parallel, without any current flow between them. Even if you have resistance in the cabling, there would be current flow and a voltage drop across the cables if the packs are at different voltages. If there is no current flow the voltages should be the same - ohms law dictates that. Have you tried measuring the voltages with a DMM?

As one pack disables the charging, it will immediately start coming down in voltage, because the mosffett's will be shutdown
The other is still charging , thus will have a higher voltage

I think OP is very close to where he needs to be

 

[Oldman2]

After reaching 100% B1 & B2 alternated with +-0.21A while B3 sat with zero Amps. Once that stopped all 3 Batteries with zero amps the pack voltage started to drop.
Quick bms checks showed B1 53.726v B2 53.720v and B3 53.703v a spread of.023v B1-B3.
Another check showed B1 53.696v B2 53.692v and B3 53.672v a spread of .024v B1-B3.

All cells in all batts have 1-2mV volt-diff with 3.349v being highest & 3.347v being lowest.

So these appear nice and close together and grateful as I am for the assistance, but, there is always a but.. If the packs have a full voltage of 55.20v for 5.12kWh surely I am a dollar short of full charge? I'm guessing this is due to us lowering the balance threshold to 3.40v from 3.45v?

 

[houseofancients]

After reaching 100% B1 & B2 alternated with +-0.21A while B3 sat with zero Amps. Once that stopped all 3 Batteries with zero amps the pack voltage started to drop.
Quick bms checks showed B1 53.726v B2 53.720v and B3 53.703v a spread of.023v B1-B3.
Another check showed B1 53.696v B2 53.692v and B3 53.672v a spread of .024v B1-B3.

All cells in all batts have 1-2mV volt-diff with 3.349v being highest & 3.347v being lowest.

So these appear nice and close together and grateful as I am for the assistance, but, there is always a but.. If the packs have a full voltage of 55.20v for 5.12kWh surely I am a dollar short of full charge? I'm guessing this is due to us lowering the balance threshold to 3.40v from 3.45v?

Yes, but, there is next to -0- power to be gained above 3.45v , and going over that is usually done to ensure faster balancing..

You sir, have a mighty fine and balanced bank right there !

 

[Quattrohead]

Think of it like this, you have just had an extremely large lunch (bulk charge) and now you need to sit down and digest and distribute it a bit (float and balancing) then you are ready to take a dump (power loads)

 

[Oldman2]

I checked the BMS memory info via Pbmstools today and found it had recorded a couple of errors yesterday with Battery1 cell 10. Anything I should tweak to stop this in future?
Here are the current parameters followed by the memory info.

 

[Oldman2]

I'm still in a tight spot here with alarms from the BMS's.
As well as the above "Fully" alarms on Battery 1.
Battery 2 & 3 are also alarming daily since 9th Aug with "Fully"
Looks to me like its when the pack volts goes over 55.2v as all the errors are with pack voltage of 55.3v up to 55.75v
These alarms are kept "in house" by the BMS, they don't appear to halt the battery, just give a red warning on the battery display screen which goes once the voltage drops.
I have the xls files from the BMS memory but they are just more of the above in post #49 really.
Parameters set are as post #49.

 

[houseofancients]

I'm still in a tight spot here with alarms from the BMS's.
As well as the above "Fully" alarms on Battery 1.
Battery 2 & 3 are also alarming daily since 9th Aug with "Fully"
Looks to me like its when the pack volts goes over 55.2v as all the errors are with pack voltage of 55.3v up to 55.75v
These alarms are kept "in house" by the BMS, they don't appear to halt the battery, just give a red warning on the battery display screen which goes once the voltage drops.
I have the xls files from the BMS memory but they are just more of the above in post #49 really.
Parameters set are as post #49.

Don't worry about the alarms, they are part of normal operations.
Just enjoy your power

 

[SeaGal]

Maybe I missed something, but I don't see anything wrong with those values - both cell #10 and the pack voltage are within the ranges you have set, so not sure what 'alarm' you are seeing?

Do the red lines on the spreadsheet mean anything, or are they just alternating with black to make it easier to see the rows? The pack voltage values in the black row are actually higher than the red one.

 

[Oldman2]

Not sure if this will help or not but here is a screenshot of a memory dump on B2 which includes the testing done before delivery.
Going on the alarms in April I would say its safe to assume that the red lines are the fault reports.
I'm not sure I can post a complete xls file here for viewing.
Again i'm guessing but I assumed that the black lines are after the alarms triggered but the volts are still rising?

 

[houseofancients]

Not sure if this will help or not but here is a screenshot of a memory dump on B2 which includes the testing done before delivery.
View attachment 162851Going on the alarms in April I would say its safe to assume that the red lines are the fault reports.
I'm not sure I can post a complete xls file here for viewing.
Again i'm guessing but I assumed that the black lines are after the alarms triggered but the volts are still rising?

These are NOT fault reports, these are alarms of overvoltage/voltage reached, and thus battery full..
Again, stop fiddling and start enjoying

 

[Oldman2]

Sorry if I have offended, I am happy to enjoy and I would rather not fiddle. I am going to lay the blame firmly at the large LCD display on each battery that shouts at me thus.


Inviting a button press to alarm status information which gets even more red.

 

[SeaGal]

These are NOT fault reports, these are alarms of overvoltage/voltage reached, and thus battery full..
Again, stop fiddling and start enjoying

My thoughts exactly.

For some odd reason it seems the PACE BMS is reporting "fully charged" as an error and thus confusing the users. Why would it show a big red indicator when it's just fully charged? @Ben@Fogstar

 

[gustaff]

I too am getting these alarms on my battery and my inverter ( Solis S5-EH1P5K-L) is alarming and shutting down for about 15 mins until it sorts itself out. It always occurs as the battery is fully charged. I have asked Solis to update the software to see if it helps, but there seems to be some parameter that the inverter does not like. Anyone any suggestions as to what I can do to fix this.

 

[SeaGal]

What batteries do you have and what errors are they giving. What does the info page re BMS data show - it seems odd you are getting both a no battery and BMS high volt alarm as well as a grid frequency alarm.

 

[gustaff]

It is a fogstar rack battery the battery has shown the same warning as @Oldman2 above and also cell overvoltage warning. It had already shown the fully warning and was continuing to charge, it was 55.8+ but by the time I had grabbed my camera it was starting to come down. I have contacted Solis and installed a data logger next week I will ask them to update the software and alert them to the alarms, but my gut feeling is it is the battery.

 

[SeaGal]

I assume you have checked all the settings on the BMS are correct. What are your over cell and over pack voltages set to and what charge voltage is the BMS requesting of the Solis?