On Nov 17, 2010, at 6:59 PM, Doug Hughes wrote: > not at 2kw. batteries don't make any noise. On the other hand, in > contrast to what somebody else said, UPS's do make some noise as a > result of transformation and cooling/venting fans. The larger it is, the > more noise you'll get as a result. In your case, ~2kw is pretty tiny.
Different UPSes from different vendors will make different amounts of sound. Do careful testing before you accept anything. Years back, I was doing testing of 2kVA UPSes, and we were going to buy 50-100 of whichever unit we decided we liked best. I got one test unit from APC that sounded like a chainsaw that was being used to cut your head off, and I called them up to complain about it -- told them how many we were looking to buy, etc.... Nothing fazed them and they were going to write me off -- until I held the phone up pointed in the general direction of the unit in question, which was about a couple of feet away from the receiver. As I brought the receiver back towards my head, the next words I heard were "...arriving by FedEx Next-Day-Air". Good UPSes should not sound like chainsaws. > If you're going to strike out on your own anyway, deep cycle marine > batteries are what you want. They are much heavier and have more lead > content than car batteries. Car batteries are usually porous and are not > designed for deep discharge cycles whereas deep cycle batteries are. In the early days of the new operations facility at Reston, AOL had pre-populated the entire 1st floor of the building with old battery packs that had been scavenged from Whiskey-class submarines, a design that dated from WW-II. We ran like that for months and months, while the backup generators and redundant mains power feeds were slowly installed over time. What really nailed us was the day they were installing the third generator (of which only two were actually needed for full emergency operations) as well as the backup power mains, and somehow managed to generate a short circuit that fried the second generator as well as both sets of power mains. At least we got a nice company-wide picnic out of it. ;-) -- Brad Knowles <[email protected]> LinkedIn Profile: <http://tinyurl.com/y8kpxu> _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
