Lead acid battery charging using generator

Hello,

I am trying to recharge four batteries of 12v each and 33Ah (12x4volt/33Ah) using arduino for computing. what programming i need to charge batteries upto a specific potential and cut off generator after that.

What are the particulars of charging this batteries?. I mean: do you need to control the speed (corrent) of charging?. How? Do you need/want to have a log?. What are the security -if any- concerns?. Etcetera . . .

Regards