SMA SUnny Island slow charging cegasa lithium batteries

[mafu]

Hi all, I have three SMA Sunny Island 8.0H-11. I just got some new Cegasa eBick Pro 280 batteries, they are 8 modules. These are the first lithium batteries I have and I do not know exactly how it all works. My understanding was that you set a new batterie on the SI and set it to lithium external BMS and no other configuration is needed.

The problem I am having is that the batteries are going to be at for example 70% SOC and SI will rise frequency and there fore PV power is reduced (using fronius AC coupled inverters), charging the batteries at only 1,5kW.

I do not understand why they charge so slow, the batteries control panel show that for this SOC it can charge up to 648 amps. I am attaching a photo of the control panel HMI (the photo is not of when charging only 1,5kW).

Does anybody have experience with SI and lithium or with Cegasa batteries and can help me?

Thank you

 

[1201]

Have you checked the ac charging current settings?

 

[mafu]

Have you checked the ac charging current settings?

It is currently set to 26 amps. What I find odd is that I have seen it charge the batteries at 10kW on solar. But sometimes it just goes real slow even if there is plenty of sun. As well as if starting the generator it will charge with more current

 

[1201]

It is currently set to 26 amps. What I find odd is that I have seen it charge the batteries at 10kW on solar. But sometimes it just goes real slow even if there is plenty of sun. As well as if starting the generator it will charge with more current

Ok. So when you set the better type to lithium you no longer have access to voltage settings correct? It gets all that from the bms?

 

[mafu]

Yes, it is my understanding that the inverters get all the data from BMS. I can only set a max charge voltage and current, but manual says it gets overrided by data from BMS, but I can't find the bost and float voltages like with VRLA batteries.
I have tried to contact SMA to determin if the reduction in charge current is because of the BMS or because of the SI, but haven't heard from them. What makes me suspicios of it being the SI is that if I start the generator, and therefore the frequency can't go up to 51Hz and reduce PV generation, I can charge the batteries with high current.

 

[kommando]

There is an issue with the Lithium setting on the SI, tell your BMS you want a target 100SOC voltage of 55.2V and the SI will take 1v off and go for 54.2V. Result is you never get to 100%, so I set my BMS to 56.2V and the SI goes for 55.2V which is my target 100%.

My comment and link to where I found someone else with same issue.

DIY 280AH battery JK BMS JK-PB2A16S20P Canbus to SMA 5048

So the si changes it's voltage settings based on the bms? That's very interesting. Need to play around more to find out 100%, the JK is set to Goodwe Canbus so must find out what info that sends to the SI, if there is no voltage info then I must be wrong. The voltage reading the SI has on its...

diysolarforum.com

 

[mafu]

There is an issue with the Lithium setting on the SI, tell your BMS you want a target 100SOC voltage of 55.2V and the SI will take 1v off and go for 54.2V. Result is you never get to 100%, so I set my BMS to 56.2V and the SI goes for 55.2V which is my target 100%.

My comment and link to where I found someone else with same issue.

DIY 280AH battery JK BMS JK-PB2A16S20P Canbus to SMA 5048

So the si changes it's voltage settings based on the bms? That's very interesting. Need to play around more to find out 100%, the JK is set to Goodwe Canbus so must find out what info that sends to the SI, if there is no voltage info then I must be wrong. The voltage reading the SI has on its...

diysolarforum.com

Thank you very much, I will look into it. Unfortunately, I do not have access to those configurations in my BMS, so will have to see how to solve. At the moment it is dropping voltaje to float voltage of 50.4V when it reaches 80% SoC. So only charging at 30 amps at the moment, which is crazy little for a 2240Ah battery. Will never manage to charge the battery bank just on solar this way. Still don't understand why when starting the generator it will charge at higher current and only fo slow when on solar. Makes me suspicious there is something with the SI.

 

[1201]

Thank you very much, I will look into it. Unfortunately, I do not have access to those configurations in my BMS, so will have to see how to solve. At the moment it is dropping voltaje to float voltage of 50.4V when it reaches 80% SoC. So only charging at 30 amps at the moment, which is crazy little for a 2240Ah battery. Will never manage to charge the battery bank just on solar this way. Still don't understand why when starting the generator it will charge at higher current and only fo slow when on solar. Makes me suspicious there is something with the SI.

Is the 50.4v float set on sunny island or bms?

 

[1201]

Yes, it is my understanding that the inverters get all the data from BMS. I can only set a max charge voltage and current, but manual says it gets overrided by data from BMS, but I can't find the bost and float voltages like with VRLA batteries.
I have tried to contact SMA to determin if the reduction in charge current is because of the BMS or because of the SI, but haven't heard from them. What makes me suspicios of it being the SI is that if I start the generator, and therefore the frequency can't go up to 51Hz and reduce PV generation, I can charge the batteries with high current.

Whats your charge voltage set to?

 

[mafu]

Is the 50.4v float set on sunny island or bms?

I could not find any charge voltage settings on the SI when battery type is set to external-bms. So I do not know who is setting the voltage. Because I can't see that information on the BMS either

 

[kommando]

Have a look at the parameter 222.13 BatChrgVtgMan and see what it is set to.

 

[mafu]

Have a look at the parameter 222.13 BatChrgVtgMan and see what it is set to.

That one is on default value of 54V

 

[kommando]

On my SI5048 that figure changes to 55.2v which is the target voltage -1V set on my JK BMS.

 

[kommando]

What Canbus protocol is the battery set to, Pylontech is compatible with SMA but provides less info than the full SMA Canbus specification.

 

[mafu]

What Canbus protocol is the battery set to, Pylontech is compatible with SMA but provides less info than the full SMA Canbus specification.

I do not know that. The Cegasa BMS does not allow any configuration and documentation doesn't tell what protocol it is using. I got them because according to SMA they are compatible with Sunny Island. I am not at home now, but will try to get all settings on SI remotely through modbus.
I also just got the modbus register map for the BMS, so will try to find what voltages are set there

 

[mafu]

What I do not know is what parameters should I configure when using lithium batteries with an external BMS. Does for example BoostTime parameter affect now or is that only with lead acid?

 

[mafu]

There is an issue with the Lithium setting on the SI, tell your BMS you want a target 100SOC voltage of 55.2V and the SI will take 1v off and go for 54.2V. Result is you never get to 100%, so I set my BMS to 56.2V and the SI goes for 55.2V which is my target 100%.

My comment and link to where I found someone else with same issue.

DIY 280AH battery JK BMS JK-PB2A16S20P Canbus to SMA 5048

So the si changes it's voltage settings based on the bms? That's very interesting. Need to play around more to find out 100%, the JK is set to Goodwe Canbus so must find out what info that sends to the SI, if there is no voltage info then I must be wrong. The voltage reading the SI has on its...

diysolarforum.com

Ok, I can confirm from de BMS modbus register that it is sending a charge voltage and Sunny Island is charging at that voltage -1V. Altough I think the BMS charge voltage is a bit low, that is another problem to solve.

Unfortunately I think there is no way to change the charge voltage on my BMS. I am also concerned that changing it on the BMS will void my warranty. Is there no way to change this on the Sunny Island? I still have no word from SMA support on this problem.

I am also considering to change my inverters to Victron Quattro if I can't solve the SMA charging problem, otherwise 50% of my PV generation is just wasted always. But would like to leave that as a last resort

 

[kommando]

This -1V bug seems to be inconsistent. See post 6 on an SI-6048US

Top Balancing using SI-6048?

Hello, It appears I pulled a rookie-move and had my JK PB2A16s20p balancing turned on when the cells were at 70%, where they came from the factory. I didn't realize I was possibly doing harm... now I know. In any case, I have five of these BMS, five 48v 280ah packs. The cells are...

diysolarforum.com

I am running SI6048 firmware 7.304/7.300, so maybe its a bug that is firmware specific or only affects 50htz (mine is 50htz) and not 60htz.

If you could change it on the BMS then like mine as long as the BMS V target is below 3.65V per cell the SMA will never get near the 3.65V.

Can you access BatChrgVtg and change it, I can but within a few hours it drops to the BMS V -1V as the BMS must override it at some point.

 

[mafu]

This -1V bug seems to be inconsistent. See post 6 on an SI-6048US

Top Balancing using SI-6048?

Hello, It appears I pulled a rookie-move and had my JK PB2A16s20p balancing turned on when the cells were at 70%, where they came from the factory. I didn't realize I was possibly doing harm... now I know. In any case, I have five of these BMS, five 48v 280ah packs. The cells are...

diysolarforum.com

I am running SI6048 firmware 7.304/7.300, so maybe its a bug that is firmware specific or only affects 50htz (mine is 50htz) and not 60htz.

If you could change it on the BMS then like mine as long as the BMS V target is below 3.65V per cell the SMA will never get near the 3.65V.

Can you access BatChrgVtg and change it, I can but within a few hours it drops to the BMS V -1V as the BMS must override it at some point.

I can't try changing that parameter because I am not in the site now. So I can only change the registers available through Modbus and I think that one is not there. It is not that well documented. But something very interesting I have just discovered is that the Sunny Island is not consistent with the -1V on charge voltage. If the BMS is sending 51.4V through CAN and SI is charging on solar, it will do -1V. But if I start up my backup generator, the BMS still sends 51.4V and the Sunny Island reports charge voltage as 51.4V.

So now it really has me confused on what is going on and makes me worry it can't just be solved with increasing the charge voltage on the BMS by 1V. Because then if I try to charge with generator it will go too high.

I still have no word from SMA support. I opened my ticket on the SMA support portal almost 10 days ago an nothing. I have also written to SMA Latam and also have no answer from them. I think the Victron start to look like my only option. Any other ideas on what could I try?

Edit: I wonder if this lower voltage when charging with solar is due to the frequency shifting power control. And if a large load goes off all of the sudden, there would be too much solar generation untill the SI increases the frequency and therefore a spike in battery voltage. And this way the spike would be under the max voltage. But if it is like this I think it is very stupid, because you will never manage to fully charge with solar with that lower voltage