Cell balancing on the Lynx

[txwheel]

I'm a bit confused about cell balancing on the Lynx.

The general consensus is that the Lynx's smart BMS begins balancing the cells only after some of the cells start exceeding 4.2V, with the cells above 4.2V sending their excess voltage to cells that are still below 4.2V, and the smart BMS steadily stepping down the amount of current it pulls from the charger as the cells get more balanced and approach the target voltage, until the current finally stops flowing altogether from the charger. However, I notice that if the charger is set to deliver 151.2V,  charging stops at 151.2V, but after the cells rest for a bit,  all the cells end up slightly below 4.2V, (see screenshot attached).  

This leaves me with a few questions: 

1) When doing a full charge to balance all of the cells, shouldn't the charger be set to deliver slightly more than 151.2V, such as 151.3V, to ensure the balancing process completes before any current from the charger stops? 

2) If using a smart charger with a custom cut-off based on current flow (such as the Roger SC charger), what is a good current level to set the shut-off to occur at?

3) I've seen suggestions to balance the cells every month or every five or so charge cycles.  However, what is the point of balancing the cells if their voltages aren't drifting apart beyond a minimal amount? I'm wondering if it's simply sufficient to keep an eye on the individual cells, and as long as they stay balanced within a certain range, we can avoid balancing and stick to shallow battery cycles (staying within 40-80% of full charge) to minimize battery stress, and only balance if/when we eventually see the voltage variance drifting outside that range?

4)At what "max diff" level can the cells be considered balanced, or is there another way to gauge if balancing is complete?

Edited June 7 by txwheel

[sffish]

I adjusted my stock charger (I don't remember the voltage it puts out) so that my individual cells never go above 4.2V at fully charged. They are all 4.19 or 4.18 at the end of charging. To me that seems like balancing.

[txwheel]

Thanks @sffish.   I wonder if there's any point to charging to 100% if the cells' voltages stay closely balanced.   Some folks recommend occasionally charging to full, but isn't there no reason to do that as long as the voltages don't drift apart much?

[sffish]

I suppose not if the batteries balance at a lower voltage. I just want to get my maximum range so I don't mind sacrificing some battery longevity for that. I just don't want to overcharge the batteries.

[peytole]

no need to charge above 151 volts.  Smart BMS balance cells continuously from rated voltage.  Always wanting to fully charge is not good.  Stopping at 150 is fine too.  I carried out around twenty charges between 125 and 145 volts and I did not notice any imbalance.  The BMS have a tolerance and do not cut off the charge at 4.2v, if the charger is incorrectly adjusted you will charge at 152 or more without cutoff.  So have the charger voltage checked and lowered to 151 volts maximum.