Originally Posted by choctawmel
....... With 3 dead batteries it took out the alternator before we got home.
Most shops have some *really* big battery chargers. They will (if turned all the way up) put a couple hundred amps of charge current into the batteries. The gotcha is that they need a pretty hefty AC circuit to keep them happy.
The application (as you have found) is recharging "big" battery setups so that folks can get back on the road. Without the boost, yes, the alternator will fry at some point down the road. If three batteries works out to ~500AH of capacity, even with one of those monsters doing the job, it'll take ~4 hours to be ready to roll down the road.