Highest recommended voltage drop range to pair up modules?

Where did you get that the pack max amp is 100A? As other commented, since these are in series, the total max amperage is the same as the amperage the weakest module can give.

 

Using Dr. Prius android app, I can see the max amps for the whole pack is about 90 amps. That is what I noticed, but I rounded up to 100 amps. There is a 125 amp fuse in the safety plug, so the total amps can't be much higher than 100 amps. I personally found charging a single module @ 3.2 amps up to 8.60v worked good to rejuvenate a module. My chargers can charge at 5.2 amps, but the module can get too warm, and may expand damaging the module. I don't compress the module, and I have a fan on the single module when charging, but I noticed it starts getting warm once past 8.40 volts. I also watch the temp of the module. When the air is 72F and the module gets to 90F, I stop charging. When the car is running, the pack can get to 125F pretty easily, but the pack is compressed and air is being blown thru the pack. I personally think charging a single module at 6.5 amps is too much. I have tried 5.2 amps, but I suspect I may have damaged a module or two doing this.

 

I am planning to charge at 0.345A as the prolong charger based on recommendations... what is the discharge voltage? until it start dropping quickly? I bought 2 ZB2L3 battery capacity tester, and 3 ohm 100W resistors to discharge it.. with them I can setup the cut off voltage, which many recommend at 6 or 5.8.. but on some test I did, the voltage start dropped quickly at 6.5 so the ZB2L3 tester detects that drop and stop discharging... and give me how much capacity the battery has as an added bonus.