Is operating alternator at near max capacity hard on charging system. I have 55 watt passing lamps and 55 watt headlight. At idle battery voltage will be 11.5 volts, but off idle comes right up to 14. No issues with weak battery
Operating it near max constantly will cause it to run hotter than normal service and more than likely take a bit of life off the end of the duty cycle. I would use the passing lights when needed instead of running them all the time so as not to overwork the alternator as much.