? one bad apple?

[Barry Fields]

If I have a 6 cell FLA battery where 5 cells are @ 1.26 SG (100%soc) and 1 cell @ 1.22 SG (75%soc), what do I do next?

If I equalize @ 15.6 volts (2.6v/cell), am I over charging the "good cells" and shortening their life?

Might it be better to "step charge" the battery @ 12.6v (2.1v/cell) wait 13.2v (2.2v/cell) wait  13.8 (2.3v/cell) wait  then float voltage.

Wait and finish times could be determined by current taper.

Just asking.

[boB]

What is the resting voltage of each battery compared to the 1.22 SG one ?

[Barry Fields]

This is purely hypothetical based on ONE FLA battery with 6 internally connected cells. Individual cell voltages would not be available.

hope this does not complicate things but life is not easy.

[Barry Fields]

I started this post because we all know that cell equalization is important. How to best achieve that is another question.

Not all batteries have individual cells for a BMS to access. Therefore it must be done through a charge process.

I have attached a response from MK Batteries related to this endeavor.

My take away is charge slower but not too slow.  A step charging regimen might help.

I know some will say that we have always done 3 stage charging and will find it hard to let go. Ok I am reinventing the wheel, but consider without reinventing the wheel is why we are not driving on stone tires. 

[Barry Fields]

On reflection, this step process is kinda happening with solar charging. The sun comes up and the charge current slowly increases until absorb is reached.  This process is uncontrolled and varies from system to system. Some intervention might be a good idea for prolonged battery life.

It may be more important to bridle utility (generator/inverter) charging where currents immediately go to maximum.

The goal here is to charge evenly and rapidly without toasting the best cells.

[ClassicCrazy]

When you have a big battery and limited solar charging time, you want to put as much power in as possible in the time you have. That time is even more limited on days that may get cloudy and especially on short days of winter.  That is why lithium are so much nicer to charge than lead acid . The lead acid will keep cutting back the current in absorb until full . With lithium you can charge the (recommended) limit until full.
So there is the ideal charging for lead acid , but difficult to  achieve that in the real world of solar power systems that many of us have.
Larry 

[Barry Fields]

But we can try.

[ClassicCrazy]

But we can try.

Yeah it doesn't hurt to try new things.
I didn't understand at first that you were talking about monitoring the Float current to find the point where to end Absorb ?
Larry

[Barry Fields]

https://midniteftp.com/forum/index.php?action=dlattach;attach=10038

Kind of a lather rinse repeat process.