Overkill bms setup queries

[ian123]

So my setup is 3.29v lifeboat cells X 4 to create 12v battery with 272amps. I have two of these to provide 544 amps. Each is controlled by an overkill solar bms.

the bms read data screen prints below. I adjusted the total battery capacity to 272000, total cycle capacity to 80% of that. I’m not sure these are set correct:

Cell full voltage
Cell min voltage
Cell 80%, 60%,40%, 20%

all Protections.

help!
Tia from a newbie

 

[Gazoo]

With my 8 cells, those setting are close enough. They can always be changed later. Also keep in mind the battery needs to be fully cycled to get an accurate SOC reading.

Your delta of .219 is terrible and those cells are out of balance. Did you parallel top balance your cells or do you intend to? I would be more concerned about getting the cells to a more even voltage.

 

[Antonio cianciardo]

Hello
I’m having the same problem but my battery it’s 200ah . I did overnight parallel and next day the some thing happens again

 

[wholybee]

Hello
I’m having the same problem but my battery it’s 200ah . I did overnight parallel and next day the some thing happens again

Did you follow these directions for top balance, or do something else? The directions below work. Lots of other techniques do not.

Top Balancing LiFePo4 Cells using a low cost benchtop power supply.

To get the paper, click on the orange at the top of this page. This is a tutorial with detailed steps on how I top-balance my LiFePO4 Cells using a low-cost benchtop power supply. To get the tutorial, click on the orange "Download" button...

diysolarforum.com

 

[babybober]

Hello
I’m having the same problem but my battery it’s 200ah . I did overnight parallel and next day the some thing happens again

I will second @wholybee . I am using 150ah cells and am on about 24 hrs now of parallel charging 4 batteries together to top balance. I started at 3.291v +/- .001v. The cells are now at 3.360 +/- .001 so I a getting closer but not there yet. That is with a cv/cc ps set at 3.65v/ 10a output. Overnight just doesn’t sound correct.

 

[Antonio cianciardo]

I will second @wholybee . I am using 150ah cells and am on about 24 hrs now of parallel charging 4 batteries together to top balance. I started at 3.291v +/- .001v. The cells are now at 3.360 +/- .001 so I a getting closer but not there yet. That is with a cv/cc ps set at 3.65v/ 10a output. Overnight just doesn’t sound correct.

Remember you have a 4 150ah cells so 10amps charge on 24hrs is not that much time

 

[babybober]

Remember you have a 4 150ah cells so 10amps charge on 24hrs is not that much time

Yes I know. I was responding to your comment that you paralleled overnight to top balance . If just overnight with 200ah cells you probably didn’t do much unless you were already at 98% charge…

 

[Antonio cianciardo]

Yes I know. I was responding to your comment that you paralleled overnight to top balance . If just overnight with 200ah cells you probably didn’t do much unless you were already at 98% charge…

Oh ok got it, now I put my cells on parallel with a charger at 3.65v and I will wait till the charger stop charging and then do the 4s again and try again