You're right, 30 amps is not enough. However, if you go with the 100 amp Balmar, you should make sure the regulator is a "smart" one and able to take advantage of the higher output, and that you're battery set-up will benefit from the upgrade, too. (It makes no sense to have a 100 amp alt. if your battery bank is too small.) Also, make sure the mounting foot of the Balmar mates well with the Universal and that the belt pulleys align, or you'll shred belts.