I don't know your background in electrics, but you seem to confuse a few things. Voltage is critical, you can't talk amps without volts. Maybe you can share the name and model of that generator, I can look it up. Also, typical generators output AC current, which cannot be used directly in EV.
When batteries connect in series you add voltage, not amps, so you can't give each battery a portion of amps, doesn't work like that. You have total voltage of the battery string and you have to supply exactly correct voltage to charge them. Voltage is more important than amps.
If you really want electric drivetrain you need to design battery/controller/motor part first. Then you add charging circuit to it. You seem to pile it all up, but maybe its just the way it comes out in your posts, I don't know.
Again, I am assuming its a typical AC generator, in which case you also need a charger to convert AC to DC, which usually is not big enough to charge while driving. Real series hybrid needs a DC generator big enough to generate same amount of energy as the car uses to drive.
Most generators are rated by power level, like 3000 Watts or 5000 Watts or whatever. Does your generator have such rating? You can't design an EV not knowing Watts, Volts and Amps and how they relate to each other.