flippy said:
many people dont read/understand datasheets properly. not blaming you, datasheets are hard to pick apart even for engineers sometimes.
dont forget, a full cell should keep itself at 4.2v anyways. so floating it should do exactly nothing.
The cell can certainly keep on taking energy post termination voltage and be what is called " overcharged" and create a dangerous situation. Go charge a cell to 5 volts.. energy WILL flow, top of charge, the resistance will climb, cell will get hot, and thermal runnaway a possibility? They dont just magically stop taking power at 4.25v? I dont get what you say.
I am certainly read the datasheet correctly, know the definition of termination current, and also have many datasheets that state a different ( than 4.25v/) termination voltage inherent. I have had some personalized tutorials from LGX approved intergrators on the subject. We all know how resistance climbs on the top and bottom of a charge. On any chemistry.... Lead through lithium... alike. In storage battery engineering.
Current C/? is a standard lithium type termination that stops the charge when a current is below a ration set by the charge current (MATH?, SCIENCE?). Typically termination should be C/10.
Fallback termination is another. Used by NiCd and NiMh. For an example.
Another type of termination is when the cell voltage reaches the charge voltage set point. This termination is the quickest, because it stops the charge rather than tops off the pack...... perhaps this is what you refer to.
I did not make this up.
Every LG datasheet I have seen has a C/? in it, right nest to standard charge, standard discharge, ect. Every one. Different chemistry are different.
I really dont know what a "4.25v balance trigger is". Cheap universal BMS algorithms? Is that what you are talking about?
I do proper termination currents and get full logs. Takes the correct time. On the correct cell voltages as per the datasheets.
Here is an example on a LiFePo of a manufacturer stated termination voltage and termination current ( to top off the cell correctly, at whetever vltage you wish to.). Then a LG 18650. Then a large 65Ah LG pouch.. If you cannot see the differences in termination current specified, (in C/?) How do you ever get repeatable results? The math would never line up, charge to charge.
Even repeatable, reliable results cell to cell. Example is a C/20 LiFePo4 cell of 25Ah. Then a 2.5Ah LG 18650. Then an E63. 65Ah lipo. All specified. You would be hard pressed to find a datasheet without this figure, IMO. I always look at if first thing to tell me what kind of cell this is gonna be.
Maybe you are talking about something else. IDK.
These sheets specify it.
3.25A. For the E63.
65/ 3.25 = 20......... C/ 20.
50mAh, and 100mAh, for fast vs slow charges on teh tiny cell. Respectively.
12.5A on the 25Ah Lifepo. C/20.