What we have are experts claiming top paralleling balancing is the better method
Do we?
I've seen the parallel step-balancing method advocated (Nordkyn, MarineHowTo, and apparently the Battery Manufacture Engineer Ghostwriter heard about it from through her work).
And the individual-cell method advocated (GWL)-- (I suggest you look closely at the voltages they are talking about though, its different from our current model and may not be representative).
But I have not found anywhere that explicitly recommends the single step balancing method over the other methods.
edit: in partial answer to my own question, I found an updated (I think) guide from GWL. It seems they now are okay with the parallel balance method to 3.55 or 3.6 vpc. [see
here (3 minute video) and
here (more extensive lifepo4 guide)]
@upnorthandpersonal you should probably take a peak at this too.
However, I will follow the instructions I feel most comfortable with and that's charging each cell individually for the reasons I gave above and the link I posted supports it.
I'm in the same boat, just currently more comfortable with a different method than you. To a degree, for a one time balance, any of the three methods is probably fine. But I do see the logic of both the step-method, and the single cell method, above that of the simple parallel method.
I think both the step-method and the single-cell method are trying to solve the same problem in different ways.
The recent bloated cell I believe is an example of this. We have no idea what happened there but my guess is that cell had a much higher state of charge than the rest or possibly a much higher IR. As I recall the parallel balancing went well. Then the pack was fully charged and a capacity test was done. After the test the cells were taken apart and that's when it was discovered one of the cells was severely bloated. It's possible had that cell been individually charged the cell would not have bloated.
I do love these discussions and I am learning so much from them. And I thank everyone for sharing and contributing.
That case is still way too weird, and way too nebulous for me to draw any conclusions from. There are still a lot of unanswered questions and a few parts of that saga that dont really add up, I've kinda lost faith in getting clear answers to.
But I think I agree with your overall concern, and its a concern I share. In the last 6ish months, I've noticed an uptick in the number of people having issues with their cells (mostly the 280's), mostly during initial balancing + testing. Now it could just be that this is the inevitable result of so many people buying grey market cells at this price point (quality control issues, and the occasional weak or out of spec cell), or it could be that the larger form factor loosely matched cells + low current AliX chargers are leading to a situation where some people are damaging cells during the initial balancing and testing, or it could just be plain and simple user error.
In any case the rise in reported problems during initial pack assembly/testing, is what has renewed my interest/concern in balancing best practices. I think the step method minimizes the chances of user error, and damage due to 'over charging' and minimizes time spent charging in the knees.