First time fully charge

[Bluewatersailor]

To day a combination of solar and charger I charge up the 400 Ah lithium for time since I installed them
Before installing them I top balance them to 3.65 v cell athpught the Amps stop going down at 5A , I left them at that, as I was time consumed and had to go away for a few days .

To day I Charging the batteries for the first time since they been put together ,
They reached 14.1v before I turned then off as one cell reach 3.65 before any of the others , cell reading, 3.48/3.48/3.65/3.55
At lower voltage they all been the same .
Will they over time sort them self out ? And should I change the MPPT to stop Charging at 14.1v until they do .
Any suggestion other then rebalance them.
I'm using a smart 123 BMS .
Thanks

 

[snoobler]

All 4 cells are definitely in the upper leg of the charge curve and probably only slightly out of sync with each other.

Not familiar with the 123 BMS. If it engages in balancing all the time, it may undo a top balance. If it can be enabled to only balance during charge and above 3.4V, that would be very effective in restoring a top balance.

Terminating at 14.1 or even 14.05 is a good idea - better than letting the BMS trip. See if it sorts itself out with subsequent cycling.

 

[Bluewatersailor]

All 4 cells are definitely in the upper leg of the charge curve and probably only slightly out of sync with each other.

Not familiar with the 123 BMS. If it engages in balancing all the time, it may undo a top balance. If it can be enabled to only balance during charge and above 3.4V, that would be very effective in restoring a top balance.

Terminating at 14.1 or even 14.05 is a good idea - better than letting the BMS trip. See if it sorts itself out with subsequent cycling.

Thanks Snoobler , peace of mind , I didn't fancy disconnecting then all to re balance them .
Yes the 123 smart has a balance setting and mine is set at 3.4v
No sooner I stop the charging they were all back together .
I will change my MPPT setting to stop at 14.1v and keep an eye on the cells for a while and see what happens

 

[Bluewatersailor]

If I may ask another question , Abs time , what is best to set this at ?

 

[snoobler]

LFP really doesn't need much absorption time, but since you're running to a bit of a lower voltage, I'd allow 30 minutes.

End of charge is typically signaled at 3.65V/cell and 0.05C tail current (5A for 100Ah battery). You can get fully charged at 3.4V provided you allow a long enough absorption time - maybe 6 hours if starting at 0.3-0.5C.

Even at lower voltages, 0.05C is a good indicator of full or nearly full charge. With it set at 14.1V, I'd be looking for the current to drop to 0.05C and set abs time accordingly.