Latest Philosopy on Classic Settings / Firmware for LFP Batteries

[Westbranch]

Lets see if I can muddy the waters here...  in BULK the charge controller will deliver all the Volts and Amps that the battery will take, Volts rises faster than Amps at the start... as FLA and AGMs have an inherent resistance, and both rise until the Absorb voltage is reached and then  the CC goes into ABSORB stage...
[ with mine set at the top end of the charge range, Amps will go straight up momentarily and the Absorb kicks in...]
Now voltage is held constant and Amps falls slowly until the EA (End Amps) value is met and then the CC goes into Float, ... some call it maintenance or trickle charge...
Did that help?

[5 Minutes 2 Midnite]

It doesn't hurt, as your explanation makes total sense.

But I am thinking I may have taken this train of thought as far as it will go until I actually plug everything in and start looking at the numbers. I will watch how the system behaves, and see how well the charge curve, based upon my initial settings, matches the specs on the cells.

Then, if I do need to inquire further I may well have "better" questions.

thanx!

[Westbranch]

when you get  even a part of it set up get an old 12v battery and watch it , make some elementary notes and then compare with the new LFP bank.  Compare and contrast is a good teaching tool.  I had 2 different chemistries, both 2nd hand,  before my AGM..  what a difference

[ClassicCrazy]

If you have the Whizbang it monitors all the amps going into and out of the battery . It will enable the SOC state of charge to work - though SOC is only a good estimate it can be pretty accurate idea of what is going one with battery capacity if it is set up good.

The ending amps feature is where you enable the Classic to stop the charging in Absorb mode based on an amp reading ( though there is still a timed stage too) . So instead of just letting the battery go from Bulk ( all available amps ) to Absorb ( for x amount of time) you have the option to have it change from Absorb to Float when it reaches x ending amps setting . X being whatever you set it for.

The SOC can also be used as control reference  for AUX contact functions.

Many lithium chargers are Constant Current and then switch to constant voltage . I think I have that right . The classic can charge with set amount of amps if you limit the output , then when it reaches Absorb is going to hold the voltage and that is Constant Voltage. 

My electric bike lithium charger will Constand Current charge 5 amps until it reaches the voltage setpoint and then it drops the current but holds the voltage. This allows the BMS balancing to work with smaller current at the top voltage .

You can read about Lithium and there are many opinions as to what is the best lithium charging scheme.  Worst things to do are take them under or over voltage or draw too much current out of them over their ratings. And getting them unbalanced in a series string will lead to voltage on some cells going too high while others are still low. That is what the balancing parts of the BMS are supposed to take care of - though they won't work on cells way out of whack .

Larry

[5 Minutes 2 Midnite]

Very clear. Thank you.

[5 Minutes 2 Midnite]

Got my DIY system up and running this past week. Charge controller is programmed and seems to be behaving well. Feeling like with the Wizzbang Jr and cell balancers the Classic can work well with a lithium ion pack.

It's been an odyssey with so many puzzle pieces, but now that's its running it all seems so "simple".

Thanks again to those who chimed in. The board is fortunate to have a solid group of 'usual suspects'.

jim


(Guess I'll need to change my handle)