Charging vs resting voltage

[robstrom]

Ironing out MT50 settings w my 206 SOK/40 Amp Tracer.
Here:
If I'm aiming for 90% SOC, the many graphs here show an appropriate voltage (13.4 - 13.45).
That's resting voltage, correct?
Charging voltage needs to be higher to create 'push'?
Higher charging voltage simply means it gets there sooner/ efficiently utilizes my limited winter solar?
So as per Will's vids, charging limit voltage at 14.6.
What stops charging at my less than 100% SOC ?

 

[fega72]

The charging limit less than 14.6V will stop it.

 

[John Frum]

Ironing out MT50 settings w my 206 SOK/40 Amp Tracer.
Here:
If I'm aiming for 90% SOC, the many graphs here show an appropriate voltage (13.4 - 13.45).
That's resting voltage, correct?
Charging voltage needs to be higher to create 'push'?
Higher charging voltage simply means it gets there sooner/ efficiently utilizes my limited winter solar?
So as per Will's vids, charging limit voltage at 14.6.
What stops charging at my less than 100% SOC ?

This 90% bandwidth managment stuff is misleading.
Most people think they will charge to 5% shy of full and discharge to 5% shy of dead empty.
I suggest you charge to pretty darn full and discharge to 10% shy of empty.
Your charge voltage and absorbtion time should be tailored to the balance of your pack and the quality of your cells.
You want to charge well into the high knee so the bms can maintain the pack balance.
But you don't wan't to charge to high lest the bms trip on cell over-voltage.
As for discharge you can custom tune that as well.
To tune your discharge cutoff target...
Discharge your pack at a representative rate until the weak cell starts to nose dive.
Record the voltage where it starts to drop fast.
For 90% depth of discharge that is usually around 3.0 volts.

 

[robstrom]

So, a further clarification.
As I'm charging, battery voltage rises, off charge it settles.
At a 13.5 volt charging voltage limit 'hard ceiling' (in the low 90sSOC), the battery will 'see' itself at 13.5 volts while charging, right.
And will stop charging, I think.
Next morning it settled, and I'm down below 13, when I want it to be higher capacitywise.
Or, am I overthinking the settle rate?
I literally am never using enough each day at this point that its ever charging more than 10 amps at any point anyway, below.1C

 

[John Frum]

Have a look at this, I will be glad to answer any follow up questions.

How charging works in the context of LFP batteries

How charging works in the context of LFP batteries

diysolarforum.com

 

[John Frum]

Any voltage above 3.45 per cell will get an LFP battery full.
Charging at higher voltages allows that to happen quicker and it allows the BMS to better maintain the battery balance.
~3.4 volts is full resting voltage.
People either don't know about or forget about absorption.
The popular big blue cells should not be fully absorbed.
The higher the bulk voltage the less absorption time is required.

 

[John Frum]

Forgot to mention charge current.
The amount of charge current during the cc phase also matters.

 

[robstrom]

That doc helped immensely, thanks

 

[robstrom]

Now that I have the solar disconnect installed, I can sort out the charging vs resting voltage issue myself.
The question: How long does it take for my SOK 206 to show actual 'state of charge', with no charge or load? At rest.

 

[midahar]

Was it well proud that said the charge at 3.6 per c e l l and absorption is just a time to thing right well I mean if you can moderate monitor the current draw then you can tell when it's full cuz the current will tAP e r off

 

[midahar]

I hate Google I said but Google couldn't get it right was it will p r o w s e who said charge at 3.6 now I might remember wrong but like I said if you can monitor the current draw then you know when it's packed full because the current drove draw drops when it fills up

 

[midahar]

As for me I'm after a longevity so I will go to 90% SOC probably 90 on the high side 20 on the low side