Cell voltage rises in seconds during charging with Victron 150/30

[eddy.fischer]

Hi Gurus,
I started with Solar-DIY about 2 years ago and still have minimum knowledge. Most of the infromation I have is from Andy Offgrid-Garage ( https://www.youtube.com/@OffGridGarageAustralia) . The setting of my Victron 150/30 and JK BMS is originally from Andy.

My project:
Battery -> 16 EVE Cells 105Ah from Alibaba (These were balanced using ZKETECH bis 3.65V (1A). After a coupke of weeks the balancing is done and I left them sit for about 3 weeks. The voltage was down to 3.2V after 3 weeks.

BMS -> JK BMS B1A20S15P (File 0.JPG is the state when Victron Charge is noct active),and File 4.JPG is the state when I activate it)

Charger -> Victron 130/35

Solar panel ->2 x 450Wp (series Max Voc 100V)

Problem: As soon as I activate the Chargcontroller Victron, the voltage of most of the cells rises to quick and the Victron went to absoption.

Anyone could help?

I will re-balance the battery with ZKETech EBC-A40L again until all the cell get 3.65V (and A = 0.1A)

In case I miss something, please let me know.

 

[Quattrohead]

#9 clearly has a connection problem.

 

[400bird]

And 6
Either connection or balance

What was connected to the cells for the 3 weeks the pack sat?

 

[eddy.fischer]

And 6
Either connection or balance

What was connected to the cells for the 3 weeks the pack sat?

I left them connected parallel for 3 weeks. Afterwards I built the 48V system (series).

 

[eddy.fischer]

#9 clearly has a connection problem.

I might need to check the resistant between (busbar) terminal

 

[Ellcon123]

As mentioned 2 cells are astray in voltage. Redo connections including BMS leads. Have you verified cell voltages with a multimeter?

Your BMS settings look ok but what are your Victron settings? Winter where I am and its only been the past few weeks I've been able to get to 100% SOC. I was having a similar issue on one pack so just had to lower the SCC voltages to stop high voltage disconnect. Balancer seems to have caught up and I'm charging to ~3.5V. Production is going to increase so still might have to redo pack connections if issues reoccur.

 

[eddy.fischer]

As mentioned 2 cells are astray in voltage. Redo connections including BMS leads. Have you verified cell voltages with a multimeter?

Your BMS settings look ok but what are your Victron settings? Winter where I am and its only been the past few weeks I've been able to get to 100% SOC. I was having a similar issue on one pack so just had to lower the SCC voltages to stop high voltage disconnect. Balancer seems to have caught up and I'm charging to ~3.5V. Production is going to increase so still might have to redo pack connections if issues reoccur.

As mentioned 2 cells are astray in voltage. Redo connections including BMS leads -> I did it twice and the second time I even soldered them .

Have you verified cell voltages with a multimeter? -> Yes I did. They were more or less the same (multimeter vs BMS)

 

[Ellcon123]

Your BMS is already in trouble at 54.73V. The SCC is set for 55.2V so I would think dropping it to 54V is a good start. Get the runners sorted and then you can reassess the SCC voltages. Your BMS is doing its job when it trips but that shouldn't be the normal mode of operation.

One concern is why #9 went to >3.7V when BMS shouldn't let it go over 3.65V?

 

[GSXR1000]

it rises so quick because your battery is already at 3.2v per cell (100% charged)

 

[Ellcon123]

3.2V is not full, just the nominal/midpoint voltage for LFP.

 

[eddy.fischer]

Your BMS is already in trouble at 54.73V. The SCC is set for 55.2V so I would think dropping it to 54V is a good start. Get the runners sorted and then you can reassess the SCC voltages. Your BMS is doing its job when it trips but that shouldn't be the normal mode of operation.

One concern is why #9 went to >3.7V when BMS shouldn't let it go over 3.65V?

Hi, thanks for the feedback. That was my concern too since the setting in BMS Cell OVP is 3.65. The Battery should have been offline right?

 

[eddy.fischer]

it rises so quick because your battery is already at 3.2v per cell (100% charged)

The cells came with 3.2V from China and I did a full load again and then discharge it to almost 2.5V. The capacity was around 108Ah. So I do not think that the cells are bad or am I missing something here?

 

[eddy.fischer]

3.2V is not full, just the nominal/midpoint voltage for LFP.

By the way, most of the cells have voltage around 3.3 - 3.4 when it was fully loaded.

 

[DIYrich]

Drop your start balance voltage to 3.30 until the pack gets balanced at 100% charged. After that, move it up to 3.38 (54.0v). If it stays balanced after a few cycles, you can move it up higher.

Might need to set your charge voltage to 54.0 volts until it balanced to avoid the over voltage. Then move up in 0.50 v increments until you reach your desired charge voltage.

 

[eddy.fischer]

Hi all, the top balance is done and the voltage was between 3.64V - 3.65V. After 30 Minutes the voltage droped to between 3.621V - 3.623V. Voltage difference was 0.002V.

 

[eddy.fischer]

During discharge I saw that the voltage drops rather quickly (up to 2.910V) but after the discharge is done it raises back to 3.32. I am not ssure if this is normal.