Only time I have with this, the guy's 6s were down near flat, but my Vector charger (does 14.6) was able to start (so the batts had at least 4 volts or the Vector would not have started--if that happens use jumper cables first, then switch to the charger)
Amps began very low and slowly rose and voltage slowly rose over the first couple hours. Then things got normal and amps started to taper again as normal. I think you can get away with doing that at least once and the batts will recover, like leaving the lights on in your car.
I don't know what the correct answer is here, IMO your amps should be rising slowly. T2R suggested not too much voltage, but how much is that? Time for a battery guru to help out. Maybe start a new thread on this to catch somebody who knows? Probably not many people following this thread anymore.