On Friday 23 Jul 2010 1:19:42 pm Abhijit Menon-Sen wrote: > Hi. > > Does anyone here know how to calculate approximately how much power an > online/double-converting/sine wave UPS consumes from the mains? I guess > that, if it has to keep N 12V batteries charged, the most power it can > consume is (a bit higher than, depending on efficiency) N*12V*c, where > c is the maximum charging current. Am I missing anything? > > (For my 1KVA online UPS, which has 3 65AH/12V batteries and charges them > at up to 6A, I speculate that the maximum power used is 6*3*12=216W, and > when the charger is "floating" to keep the batteries charged, the power > use is pretty much negligible.) > > Second, can anyone comment on the advisability of charging SLA (sealed > lead acid) batteries at currents of >=0.1C (i.e. 10% of their rated Ah > capacity or more)? My UPS vendor says they've had problems with current > that high, and the battery FAQ says <0.1C for SLAs, but battery vendors > seem to recommend 10-20% even for SLAs. Does this differ significantly > for VRLA batteries? > > Third, can anyone explain in detail the internals of a constant-voltage > battery charger? I understand the basic idea: provide as much current as > needed to maintain the voltage across the terminals at the recommended > charging level, but I don't understand enough about how batteries work > to figure out what happens when you apply a higher current, or how the > voltage is measured or maintained. > > Also, does anyone know how much I should expect to spend on a basic DC > ammeter (the nifty clamp-on hall effect ones, not an in-circuit one), > preferably in India? > > -- ams
Is this article available in English? shiv
