But your diagram is showing two 6V batteries in series giving 12V. And a 12V generator attached directly to 6V battery. Not good.
To elucidate Steves point a bit. You have two generators, each capable of 12V and 6A. And you want out 24V and 12A. The output is exactly twice the power of the input. If you are talking about doing this continuously, it cannot work.
Now, if what you mean is that you want to charge the batteries for a while say 3 hours, then get 24V and 12A for 1 hour, that is doable if the batteries are capable of producing that current continously. If the batteries are rated at 12V and 12AH they are probably not capable of providing 12A for 1 hour. The Amp Hour rating for lead acid batteries usually is when discharged over 20 hours. That would mean a discharge rate of 1.67 A. At higher discharge rates, the capacity will be considerably less, if it can even supply that kind of current at all.
Bob
To elucidate Steves point a bit. You have two generators, each capable of 12V and 6A. And you want out 24V and 12A. The output is exactly twice the power of the input. If you are talking about doing this continuously, it cannot work.
Now, if what you mean is that you want to charge the batteries for a while say 3 hours, then get 24V and 12A for 1 hour, that is doable if the batteries are capable of producing that current continously. If the batteries are rated at 12V and 12AH they are probably not capable of providing 12A for 1 hour. The Amp Hour rating for lead acid batteries usually is when discharged over 20 hours. That would mean a discharge rate of 1.67 A. At higher discharge rates, the capacity will be considerably less, if it can even supply that kind of current at all.
Bob