Charging issues on my 48 V system

[rogerv]

I have a issue with my new 48 48 system I used 16 280 amp hour eve cells and top balanced them and a JBDBMS. I’m using a 48 V Victron multi +2 3000. when charging the batteries on shore power the first 4 cells when it gets close to 100% while still in bulk or absorption mode they will jump up to 3.7 V and the BMS will shut off but this is only the first four cells. I’ve checked all the connections everything is tight and they discharge pretty even . I am using the factory default settings. this is my first build so any help would be totally appreciated

 

[John Frum]

Does you reference DVOM agree with the BMS regarding cell voltages?

 

[rogerv]

Does you reference DVOM agree with the BMS regarding cell voltages?

I did not check but I will right now

Does you reference DVOM agree with the BMS regarding cell voltages?

Yes the BMS voltage and my DVOM are the same readings. I drew the system down to about 70% and it’s fine till I get up to the finals charge before it switched the float and that’s when the first four cells jump up

 

[John Frum]

I know you indicated you top balanced the cells but they don't appear to be top balanced.
What was your top balance process?

 

[John Frum]

Also what are your BMS settings?
cell over voltage should be 3.65 volts
cell under voltage should be 2.5 volts
pack over voltage should be 58.4
pack under voltage should be 40.0

 

[John Frum]

Also how much charge current are you dumping into the battery?

 

[rogerv]

I top balanced all the cells to 3.65v in banks of four with a power supply The picture is taken right after the BMS shuts off and the cells just start coming down. The current going into the battery is 35 A from a Victron multi +2. The two pictures are the BMS settings I’m using 280 Ah eve cells

 

[John Frum]

Cell under-voltage and batt under-voltage are way to low.
should be 2.5 volts and 40 volts respectively.

I only see one picture.

You should only be balancing while charging.
Suggest you lower your charge current to 28 amps for the first few cycles.
What is your bulk/absorp voltage?
What is your float voltage?

 

[John Frum]

Battery over-voltage should be 58.4.

 

[John Frum]

You could use a resistor to bleed down the high cells.

 

[John Frum]

Since its 4 cells in a block you could use a 12 volt nominal load on those 4 cells.

 

[rogerv]

I change those parameters does the charger settings look correct

 

[rogerv]

Since its 4 cells in a block you could use a 12 volt nominal load on those 4 cells.

I brought the whole battery bank down to about 75% earlier and watched it while I was charging and it was good right up until the voltage got up to the top and then those four took off