Hi

I am an enduser of a solar installation and have no technical knowledge of how things are supposed to work to the extent to which topics are often discussed here. I do however understand statistics and graphs well so let me try and explain my current issue.

Six months ago I installed the following system:

2 x 5KW Deye inverters, 20 x 455w Haitai panels,  4 x 5kw LifePO4 Greenrich  batteries

 

The systems works exceptionally well and zero complaints around its day to day functionality. I use the bulk of my electricity consumption outside of hours in which the batteries can be charged (17:00 - 08:00). The batteries are normally fully charged around 13:00 and for the remaining 3-4 hours of decent sunlight the potential generated is simply "dumped". The initial battery capacity covers about 85% of my electricity needs outside of "charge" hours. Which also means my electricity bill came down by 80 -85% - which is what I anticipated upfront.

So given the 3-4 hours of dumped energy I have on most days I then decided to add another battery to the installation. That way I would, on most days, get the 25KW charged - and get through the night. And possibly get me 100% of the grid, 90-95% of the time. The additional battery (5th one the same make and model as the other 4) has been in for 2 weeks and it seems to be the case, unless we have serious cloud cover or rain during the day.

So now for the issue. Since the installation of the 5th battery the SOC stats has gone crazy and this is driving me nuts as I never know what the real SOC is. To me this is a critical stat to have as accurate as possible as I run my battery discharge  as low as possible to avoid paying for electricity - and that is not that straight forward with load shedding in the mix. Pre the 5th battery the SOC showed the expected gradual rise or decline in % - depending on whether it was charing of discharging. It now seems to be confused about the extra 5KW and whenever the direction of charge/discharge changes, it jumps up or down by 10-15%.

So this was over the weekend. The batteries had been set to 40%, so I would use Escom to keep it at 40 during the night. As you can see, every time there was a need for additional electric (fridge kicking in etc) the SOC would jump up by 10-15% and as soon as that need fell away it would drop down by 10-15% again. You can see on the graph the 40% "imaginary line" - as well as the 55%  "imaginary line". So is the actual SOC 40 or 55% at any given stage -makes it a bit risky to get go low in the discharge thresholds.

So it seems as if the inverters are seeing the additional 5KW capacity, and then not seeing it - etc. Is there a specific setting, or reset which was supposed to be part of the 5th batteries' installation which did not happen, and is now causing this issue?

I hope this makes sense? Any suggestion would be highly appreciate!

 

 

 

Welcome to the forum - you have quite the beefy system there. Would you care to share how the system is wired? Inverters + batteries + panels. and then can you also share your battery setup and config pages as well as your system work mode screens. All that info should help us 

Quote

So now for the issue. Since the installation of the 5th battery the SOC stats has gone crazy and this is driving me nuts as I never know what the real SOC is.

Is the ID of the 5th battery correct?
Is the 5th battery interlinked with the older 4 batteries correctly (data cable)?
Do the 5 batteries have the same firmware?
What does LiBMS screen show?

Edited March 27, 20233 yr by system32

1 hour ago, mzezman said:

Welcome to the forum - you have quite the beefy system there. Would you care to share how the system is wired? Inverters + batteries + panels. and then can you also share your battery setup and config pages as well as your system work mode screens. All that info should help us 

Thank you, let me see what I can get together

50 minutes ago, system32 said:

Is the ID of the 5th battery correct?
Is the 5th battery interlinked with the older 4 batteries correctly (data cable)?
Do the 5 batteries have the same firmware?
What does LiBMS screen show?

Thanks, I will look into those and ask again if I get stuck.

Here are two pics so long

.

I'm guessing the new battery has an issue like a bad cell and is disconnecting either when being charged or being discharged.

Edited March 27, 20233 yr by P1000

Donnerwetter!!!! With those charge and discharge setting you can have your own lighning!!!!

They are way too high, even for 5 batteries. Maybe target 20A (low) to 40A (high) per battery. Even with a low settings, you will need 20A x 5 x 50V = 5kW of PV. You have 9100W installed, and with losses you may only peak +- 8500W. So under ideal sunlight @ noon (in summer), you won't even reach 40A per battery.

Also, Somewhere on the inverter you need to tell it how much Ah of batteries you have. It should be set @ 5 x 100Ah = 500Ah.

Even if your 5 batterie's DIP switches are correct, please cycle(reset) each battery (if not done so -Should be holding reset switch in for 5 -7 sec.) and wait for all the led's to return to normal.

Nice big system you have with plenty grunt for night time consumption, just a bit light on PV. Hope you have some more roof space!!

Thanks for the response. Just a quick question on the charge discharge. Seeing that my installation is under warranty I don't want to change anything myself. Is there a risk of anything breaking or causing fire/failure issues as the current settings? Or are the paramaters just set extremely wide and the system can't get there in any event - so no need to change from a risk perspective?

 

 

37 minutes ago, Kalaharipro said:

Thanks for the response. Just a quick question on the charge discharge. Seeing that my installation is under warranty I don't want to change anything myself. Is there a risk of anything breaking or causing fire/failure issues as the current settings? Or are the paramaters just set extremely wide and the system can't get there in any event - so no need to change from a risk perspective?

 

 

No, those are the values reported by the BMS - your inverters cannot reach those values.

On 2023/03/27 at 11:43 AM, Sidewinder said:

Donnerwetter!!!! With those charge and discharge setting you can have your own lighning!!!!

They are way too high, even for 5 batteries. Maybe target 20A (low) to 40A (high) per battery. Even with a low settings, you will need 20A x 5 x 50V = 5kW of PV. You have 9100W installed, and with losses you may only peak +- 8500W. So under ideal sunlight @ noon (in summer), you won't even reach 40A per battery.

Also, Somewhere on the inverter you need to tell it how much Ah of batteries you have. It should be set @ 5 x 100Ah = 500Ah.

Even if your 5 batterie's DIP switches are correct, please cycle(reset) each battery (if not done so -Should be holding reset switch in for 5 -7 sec.) and wait for all the led's to return to normal.

Nice big system you have with plenty grunt for night time consumption, just a bit light on PV. Hope you have some more roof space!!

LiBMS is the BMS on the primary battery reporting to the inverter what it supports 725A charge / discharge (at +/-48V)
From the spec sheet, it seems that 5kW LifePO4 Greenrich  batteries are "2C" rated
725A / 5 = 125A per battery - so probably 1.25C.
725A / 5 = 145A per battery - so probably 1.5C. @JPNiemand thanks for the correction.
This does not mean the Inverter will charge / discharge at 725A x 48V = 34.8kW.
Since there are 2 x 5kW Deye inverters, you probably limited to 5+5=10kW / 48V ~= 200A.

Eg. I have 4x100A 1C batteries. They report to LiBMS 400A Charge/Discharge. My inverter is set to 150A (7.2kW).

Edited March 28, 20233 yr by system32

1 hour ago, system32 said:

LiBMS is the BMS on the primary battery reporting to the inverter what it supports 725A charge / discharge (at +/-48V)
From the spec sheet, it seems that 5kW LifePO4 Greenrich  batteries are "2C" rated
725A / 5 = 125A per battery - so probably 1.25C.
This does not mean the Inverter will charge / discharge at 725A x 48V = 34.8kW.
Since there are 2 x 5kW Deye inverters, you probably limited to 5+5=10kW / 48V ~= 200A.

Eg. I have 4x100A 1C batteries. They report to LiBMS 400A Charge/Discharge. My inverter is set to 150A (7.2kW).

Ok thanks, that makes sense then

 

Maybe a sanity check under the Battery Settings, to see whether you are operating in Voltage or Lithium mode, and whether your charging Voltage and float Voltage in the inverter's settings correspond to the battery's requirements.

Seems on the images that you are charging at 53.62V, while the battery according to the Li-BMS charges at 57.0V. Just my 2c.

7 minutes ago, GreenFields said:

Maybe a sanity check under the Battery Settings, to see whether you are operating in Voltage or Lithium mode, and whether your charging Voltage and float Voltage in the inverter's settings correspond to the battery's requirements.

Seems on the images that you are charging at 53.62V, while the battery according to the Li-BMS charges at 57.0V. Just my 2c.

Thanks I'll do that. I do not think any of the settings were changed - and all the readings prior to the additional battery worked perfectly. The 5th battery was connected to the other 4 and then the stats started going in the wrong direction.

9 hours ago, system32 said:

LiBMS is the BMS on the primary battery reporting to the inverter what it supports 725A charge / discharge (at +/-48V)
From the spec sheet, it seems that 5kW LifePO4 Greenrich  batteries are "2C" rated
725A / 5 = 125A per battery - so probably 1.25C.
This does not mean the Inverter will charge / discharge at 725A x 48V = 34.8kW.
Since there are 2 x 5kW Deye inverters, you probably limited to 5+5=10kW / 48V ~= 200A.

Eg. I have 4x100A 1C batteries. They report to LiBMS 400A Charge/Discharge. My inverter is set to 150A (7.2kW).

725/5 is 145 not 125, and that is the rating of the battery at 1.5c. 

14 hours ago, JPNiemand said:

725/5 is 145 not 125, and that is the rating of the battery at 1.5c. 

Thanks for the correction - I've fixed the original post.

I got hold of the installer. He spoke to the suppliers eventually and they asked him to update the battery software/firmware - if that makes sense. I will give feedback on the result once the update has been done.

On 2023/03/28 at 1:33 PM, Kalaharipro said:

I got hold of the installer. He spoke to the suppliers eventually and they asked him to update the battery software/firmware - if that makes sense. I will give feedback on the result once the update has been done.

Software was updated and the SOC seems to be accurate again. So it seems as if different firmware/software (even though it is the same battery type) caused the issue. As mentioned before I could clearly see that the additional battery was adding the extra capacity, the SOC was just all over the place.