Don't know about the "expert" moniker, but I've been repairing and teaching auto electrical systems for 50+ years. Your alternator should handle the cooling fan load without a problem. The charging system, whether generator or alternator, supplies all the electrical load such as ignition, lights, heater fan, etc. before applying whatever is left over to charge the battery. Even if the cooling fan draws 20 amps or more, you've still got 40 or so to carry the other loads and recharge the battery. The only time the alternator will be operating close to its full output will be immediately after starting when the starter draw from the battery is being replaced. That usually happens within the first 5 minutes of operation after starting. If the battery terminal voltage stays above 13 volts with all the accessories running, the battery will stay charged without a problem. With minimum load and a fully-charged battery, the voltage with the engine running after 15-30 minutes will stabilize somewhere in the 14-14.5 volt range.
Jerry
