Your alternator puts out enough power to charge the battery and handle the consumption of whatever electric things are turned on at the time. There is NO benefit to putting on a larger alternator.

UNLESS you have extra electric loads, such as air conditioning, or an electric waste oil heater. For most extra loads such as fog lamps and big stereos the extra consumption is within the capacity of the stock alternator.

You can calculate the load in amps by multiplying wattsXvolts. Your 55 watt alternator would handle 55X12= 660 watts. Add up the lights wipers radio whatever else is on and until you have 660 watts worth on all at the same time you are fine. After that the battery will cover the difference until it runs down.