The charging regulator should control the current, if its working. Its job is to
protect the battery from overcharging and that will prevent overcurrent.
A working regulator means the battery voltage rises to 13.8V on normal running,
which is the safe upper limit for lead-acid battery. (Any higher and bulbs will start
to burnout). In itself that should limit current to the battery
Do you have a wiring diagram for the vehicle? Or specs of the regulator - probably
good to try and check out its function.