charging current ac / dc ?

hi everyone, I was asked witch is better, ac power or dc power. a local is trying to figure out which to use and any advantages to ether one. these are my thoughts from my systems at my location. ac / dc are both a good system but the run length of the wire needed to reach your battery is what I use to decide witch system to use. on any length over 45 - 50 ft I  use ac 3 phase and any thing under 45 - 50ft I would use ether one, dependant on the parts I have at the time. the system it self is the same build less one wire but the ac power travels a longer distance for the same loses and can use a smaller awg wire saving a little $ . I find ac power lets the slip rings live longer again saving some $. also the ac power system puts the rectifier at a easy access place off the tower for easier maintenance . at the end of the day its not a major difference unless your wire run is a long one, if so use three phase ac , easier and cheaper overall . this will also let you play with voltage doublers , amperage enhancer systems , or voltage reducers for other systems like 6 volt charging and l.e.d. systems without climbing a tower for any changes. my preference is the three phase ac but there is nothing wrong with the dc type systems, just watch the wire distances. for any calculators go to { the12volt }. thanks for reading.