How do you limit amp output from an alternator?

Look up Progressive battery charge controler. These are used in the RV and marine areas. Great controllers. Amazon has them available.

 

i remember a file in resources-energy-build your own 12 volt dc generator. the alternator used was an external regulator type, the design used a fixed or variable resistor to control input voltage to the field and conversely the output voltage/amperage. i agree you would be better off with an automatic V.R. but this setup may be useful for equalizing charging.

 

i saw a generator at an equipment auction once it was used for jump starting trucks/hvy. equip. it consisted of a 1cyl. engine 12-16 hp. and 4 big truck generators not alternators, it was wired using ford start solenoids to use 1 or 4 gens. series/parallel 12 or 24 volts, was way cool but went for big bucks.

 

Most alternators have a voltage regulator. If not a charge controller for solar would work. I remember my big rig had a 130 amp alternator. I think it was a 24-volt system(several batteries) military M series was 24 volts.