Thanks, Chuck. I talked with a former colleague that has a lot of experience in specing out UPS requirements (between battery-ready and generator-ready backups at the office they have up to 5 minutes of battery backup before the gas generator is needed with a 128-hour recharge time just to support their servers and wiring racks in the office).
He thinks that at 500W needed it would give me about 12 minutes on a 1400VA. My consideration is, then, give the server 2 minutes on battery. If full power has not been returned, shut down the server but leave the modem (w/ wireless) and switch running with power for up to 6 hours. Now I need to build a server (looking at RAID5 8x2TB) for less than $1600 w/o a CPU if I can... a local custom builder quoted me $4000 today for a full system inc. CPU, RAM and DVD. -- Ryan On Aug 11, 2010, at 11:44 AM, Chuck Swiger wrote: > Hi, Ryan-- > > On Aug 11, 2010, at 8:51 AM, Ryan Coleman wrote: >> Total: 495W >> >> According to a calculator if I enter all that information: >> http://www.csgnetwork.com/upssizecalc.html >> It says that it will use 693VA. > > That sounds reasonable. The better PSUs have "80 Plus" certification for > efficiency, and that's better than the typical wall warts used for modems and > switches and the like commonly manage. (The efficiency they're assuming is a > bit over 70%; using 80% would be around 600VA.) > >> Enter that into http://www.csgnetwork.com/batterylifecalc.html >> It requires Amps... 495W / 120 voltage = 4.125 amps... doesn't seem right >> but... >> 192 hours... that's not right, right? > > Assume for discussion their number was right. In order to get 495W of output > load, the UPS needs to provide 693 volt-amps of juice to your equipment. > After the inverter and 10:1 stepup transformer used to convert 12VDC or > whatever the UPS batteries are charged to up to 120VAC, the current needed > would be 5.77 amps. However, the 12VDC battery source itself would be > getting a draw of 57 amps (ideally; again, the inverter+transformer > themselves might only rate about 90% efficiency for very good quality UPS, so > would be drawing more like 60 or 65 amps). > > A standard APC/Tripplite/whatever 700VA UPS tend so have a lead-acid battery > reasonably similar to a car battery, and typically will have around 100 > amp-hours of charge; they'd probably give you 90 minutes of backup time. But > you can look up the detailed specs of specific models and work from their > amp-hour (or watt-hour) ratings-- actually, I think I'm guestimating more > from what a 1200VA unit might provide, and a 700VA model is probably going to > provide more like 40-60 minutes of power... > > Regards, > -- > -Chuck > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org" _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
