I grabbed the logfile out of the SDcard after the second charge. This was after a big mow of a heap of wet, long grass. For some reason the mower had been in pieces for a while.

At the end of the mow SOC was at 42%, which I thought pretty good after all the work the mower did.

The black curve is voltage of battery 1. All batteries matched everywhere to better than 20mV, so I just plotted one. I should add a temperature plot too as I don't understand the curve kink around the 2-h hour mark.

SOC must be working OK, as it took 6 hours at 10V to get to the point it started to balance. Aligns well with the 58% the SOC measure thought it had. Seems to imply the battery sales literature was honest too.

The red curve is current. The charger was in CC mode for about 5 1/2 hours at 10A.

Then in CV mode where the current fell steadily to ~3A. 

The power supply got reset to a slightly higher voltage adn a 3A limit, ran in CC for a few minutes then fell steadily to effectively 0A as balancing and topoff happened.

Green curve is SOC, ramping steadily from 42% to 100%.

The blue curve shows where balancing happened. Its in error on the falling edge, I lost a few minutes of log around the shutdown.  the slope on the trailing edge was caused by some data loss.  I have a bug in the logging code I need to track down. I'm guessing some sort of race is causing the log buffer to be written twice (often) and (rarely)  a few minutes goes missing. I'm definitely no software engineer! 

The logfile includes timestamps (well, h:m:s from when mcc was turned on)  and I had to pipe the data through sort and uniq prior to plotting it.  At least its only the log thats currently known part broken.

Watching the voltage fall on charge completion (just after 6 hours) when the charger was electrically disconnected I found interesting.  Battery 1 was at 28 degrees C after the mow / at start of charge. It went on charge around 4pm.  At start of charge it was around 10C above ambient, and it likely cooled during, and moreso after charge to ambient which would have been in the low teens overnight.  I gather both the temperature and not being charged together cause that voltage drop of around 0.6V.    You can see why integrating current is needed, and just measuring voltage is next to useless to evaluate LFP StateOfCharge.