2 out of 3 Li batteries not reaching capacity ?

[gramos100]

I have 2x 200 amp batteries at full charge , 99% + they will only read 114 amps
the other 1x battery reaches 200 amps ok ,
All are the same 9.6kw Li type , installed at the same time and use the same PV array to charge .
Battery reset has been tried but made no difference .

Whichever settings adjustment I try the amps stay the same .

What else can I try ?
ideas anyone please ?

 

[Pete@SolarBatteryBarn]

What kind of batteries and charger setup?

 

[gramos100]

3x Li 200 ah / 9.6Kw from rosensolar
2x Growatt SPF 5000 TL HVM-WPV inverters , off grid

 

[Pete@SolarBatteryBarn]

Are you using BMS comm to the inverters?

 

[Ellcon123]

Where are you getting the full charge or 99% reading from? The BMS does need to reset charge counter and this will only happen if you force a full charge. You would need to get to 14V so you are getting into the knee of the voltage curve. Assume the batteries are connected in parallel?

 

[gramos100]

48v batteries, sorry.
reading from the battery SOC lcd panel

 

[gramos100]

Are you using BMS comm to the inverters?

Yes BMS linked to all batteries and both inverters RS485/ CAN

 

[Pete@SolarBatteryBarn]

Can you read the cell differential voltages on the BMSs?
What is the SOC reading on the inverters?

 

[Pete@SolarBatteryBarn]

I suggest you force a full charge by setting battery type to USE or USE2 and charge voltage to 58.4V (setting 19) and cycle the batteries from full to BMS cut-off to see if the SOC will calibrate.
Note: I have not used the Rosen batteries.

Also you may check BMS settings by connecting them to a PC with Rosen software if you can get it. Compare settings with the one that is 100 SOC. Look for Ah settings...

 

[740GLE]

Is this a discharge test? Trying to pull 200amp from a 48v battery bank?

Or a capacity test? Your units of 115a and 200a doesn’t indicate you are doing a capacity test.

So us a picture of how the three batteries are inter connected to the charge controller.

Sounds like another issue of BMS talking to an inverter and shutting off bulk charging once one battery is full and due to poor set up the others aren’t reach full capacity.

Can you shut off the “good” battery and let the other two full charge up to 100% soc then run your capacity test again?

 

[gramos100]

Can you read the cell differential voltages on the BMSs?
What is the SOC reading on the inverters?

Yes I can read cell volts , right now they show 3332

 

[gramos100]

SOC is 50.2

 

[gramos100]

I suggest you force a full charge by setting battery type to USE or USE2 and charge voltage to 58.4V (setting 19) and cycle the batteries from full to BMS cut-off to see if the SOC will calibrate.
Note: I have not used the Rosen batteries.

Also you may check BMS settings by connecting them to a PC with Rosen software if you can get it. Compare settings with the one that is 100 SOC. Look for Ah settings...

Ok thanks, now on 58.4v charging, let's see if it'll reach it , if it does then I will program back to Li on 5.
Rosen are very bad at Comms , I try every day ,aha ! Inverter just showed SOC at 58.2 v and then all batteries show Y fault which is cells at 3420 I can't get high enough to set to Li batteries.a

 

[Pete@SolarBatteryBarn]

The fault is due to the batteries getting full and the BMS tripping (expected in this case). Keep it in USE for a full cycle. Measure your kWh if possible. Hopefully you will get about 10kWh per battery. Set your BMS cutoff voltage low enought to allow your BMS to cause a low voltage battery fault.
Hopefully the SOC will calibrate.

Do you have the batteries addressed and master assigned per Rosen?

You may have to run it in USE until you get the comms sorted. If so, lower the charge voltage to stop the BMS from tripping (54.4V) and float (53.6V) and cutoff (50V).

 

[gramos100]

The fault is due to the batteries getting full and the BMS tripping (expected in this case). Keep it in USE for a full cycle. Measure your kWh if possible. Hopefully you will get about 10kWh per battery. Set your BMS cutoff voltage low enought to allow your BMS to cause a low voltage battery fault.
Hopefully the SOC will calibrate.

Do you have the batteries addressed and master assigned per Rosen?

You may have to run it in USE until you get the comms sorted. If so, lower the charge voltage to stop the BMS from tripping (54.4V) and float (53.6V) and cutoff (50V).

Thanks Pete,
Will try this tomorrow.
Yes one inverter is HST , one SL randomly selected .
I tried them again in Li mode with full sun today, fault shown as low battery, SOC on batteries was 50.1/50.2 it would not charge although 290+v pv input.
50.2 is 15% charged for Li battery !

 

[gramos100]

Is this a discharge test? Trying to pull 200amp from a 48v battery bank?

Or a capacity test? Your units of 115a and 200a doesn’t indicate you are doing a capacity test.

So us a picture of how the three batteries are inter connected to the charge controller.

Sounds like another issue of BMS talking to an inverter and shutting off bulk charging once one battery is full and due to poor set up the others aren’t reach full capacity.

Can you shut off the “good” battery and let the other two full charge up to 100% soc then run your capacity test again?

Good morning ,
ok today we have full sun , system charging .
1000 hrs 2x batteries at 51.5v A+B
1x off C
when 52.9 v shows on inverters , it shut down , 1015hrs.

settings at :
12 -46v
13 54v
19 52.4v
20 51v
warnings Y /( over voltage) on all batteries
when shutting down 52v showing.

usual daily routine then ,
switch off panels and inverters
restart inverters
power back on , batteries full .
A/B still at 114 A
C at 200 A

 

[gramos100]

After installation, I had this problem from the start , Rosen had me change the ADSL buttons, what do these actually do ? Is there any alternative setting for these ?

 

[gramos100]

After installation I had this problem from the start , Rosen had me change the ADSL buttons, what do these actually do ? Is there any alternative setting for these ?