In short, yes! I put 66Ah in a 100Ah cell starting at 3.30V and ending at 3.451V with an ending current of 476mA. These voltages are measured at the cell terminal. Then, I continued charging from 3.451V up to 3.65V and only got 1Ah in with an ending current of 420mA. So, don't assume you are a long way from filling the cell and walk away without a way to turn off the charger when a cell reaches 3.65V or less. I only charge my cells to just under 3.5V because there is so little energy above 3.45V.
HTH,
I am testing another 400ah ts that I previously tested and ran down to 2.6v. It has been on charge @ 20.4Amps for 18 hours.
1: Now the charger is putting out 3.60V and at Battery 3.39v @20.4amps. I don't see any fast voltage escalation yet and keeping a watchful eye as I want to get an idea where the top is, so I can avoid it later.
2: You state your amperage at the end of your charge is about 1/2 amp. ??? My charger is not throttling down yet.
CORRECTION UPDATE: I figured out how to set the voltage limiting amps
I am still a bit befuddled with guys and even you charging 3.451+ (seems like it will take 10 more hours at this rate, so there MUST as you said before a very sharp plateau very soon, that if u do not watch will run away on you.
CORRECTION UPDATE I witnessed the voltage go up quite quickly after 3.5v, even with a 400ah TS and only 20amps, not runaway, but I imagine could be with more current or a 100ah cell.
Francis