There are two ways to alter charging rate of a alternator one you solder a wire to brush box before regulator this would invalidate your warranty if any. cant be done on some later alternators or 2nd way is to run + cable to a box that fools regulator into charging its maximum,Sterling do one that you can connect two alternators together for even more power,this does not invalidate any warranty as it doesn't interfere with unit,it's also very easy to connect no soldering or removable of unit Bth units check temp of battery bank and adjust charging accordingly to not overheat batteries they also adjust charging rate for different types of battery, you can reduce topping up of cells by using the next lower charing rate. The rule of thumb is one v belt will run max 43 amps one serrated belt will run 65 amps twin belts which have to be matched pair 75 amps single flat ribbed starts with five groves 120 amps 7 or more groves 200 amps, to much tension on belt will wear front crank pulley. John