Ok, are the plates copper and aluminum? Are the bolts short enough to achieve full clamping on the plates?
Yes.Ok, are the plates copper and aluminum? Are the bolts short enough to achieve full clamping on the plates?
It seems odd to me that the cell voltage pic shows cells 1-8 as ~3.2V and cells 9-16 as ~2.8V.But now some cells get over discharged and the cell volt difference is 0.5mv.
Ok, each terminal needs cleaning and antiox paste, also each of the aluminum plates need to be cleaned in an alcohol bath with flat sandpaper, and assembled INSTANTLY while still wet... aluminum is a pain to assemble without having oxide layers.
The copper plates also need cleaning prior to assembly, but antiox paste needs to be used with the terminals.
Off grid garage did a video on this mess a while back.
I think these cells are taken from 2 packs ( 2 modules - 8 cells from each. These cells are not brand new). I also suspect this cause the problem. Two days back cells V went above 4.2V. It also happened in first 8 cells. (I'm not sure why JK BMS failed to shoutdown). If so, How can resolve this problem?It seems odd to me that the cell voltage pic shows cells 1-8 as ~3.2V and cells 9-16 as ~2.8V.
Is there any info on what was done with these cells (as groups of 8) or how/why the cells were placed in the order they are in now?
These cells are taken from 2 different modules I guess (8 cells from 1 module). This is random in the first 8 cells and the second.Is cell #12 the lowest at a low state charge and the highest at at a high state of charge? If so you could have a bad terminal connection or it’s a bad/weak cell. If things are random, then it’s more likely an unbalanced condition exists. If the cells are in reasonable shape, 1amp balance current applied above 3.45 vpc with enough time at or above that voltage should do the job.
About 12 hours back, I changed the start balance Volt to 3.3V and charged the pack through the Inverter. Then I saw that 1 cell (Cell #8) goes beyond 3.65V. JK BMS balance gave a red alert and reduced the Volt.Hi.
We are building a 3.2v 16 cells Lifepo4 pack, with JK BMS.
We did bottom balancing and top balancing of the pack.
But now some cells get over discharged and the cell volt difference is 0.5mv. (Also, observed that the cells gets over charged to 4v on the previous day).
In this case, 5 cells were at 2.7v and the remaining were at 3.24v.
View attachment 119153
Here is the setting of JK BMS (screenshot took bit later)
View attachment 119156
How do we set the parameters correctly to balance the pack at “top” and “bottom” both?
Your advice is highly appreciated.
Thanks,
Flash
Two days back cells V went above 4.2V. It also happened in first 8 cells. (I'm not sure why JK BMS failed to shoutdown).
Looks like it's working as designed.This is what happened when I changed to 3.45V and do the charging expecting all cells will reach to 3.65V
Delta cell Vol difference around 0.3
View attachment 119240
But this is not normal, right? Only one cell at 3.65V and all the other cells are way below that volt. That's why I'm trying to balance at 3.30V before charging again targeting 3.65V for all cells. What settings should I need to change to get there?Looks like it's working as designed.
It will take time to get it straightened back out.
If you slow the charging, it won't shut down as much.
Lower the amperage so that the balancing can keep up.But this is not normal, right? Only one cell at 3.65V and all the other cells are way below that volt. That's why I'm trying to balance at 3.30V before charging again targeting 3.65V for all cells. What settings should I need to change to get there?
This does not make sense. Your cell OVP is 3.6V.Two days back cells V went above 4.2V. It also happened in first 8 cells. (I'm not sure why JK BMS failed to shoutdown). If so, How can resolve this problem?