I'm considering a UPS to power a light load. It's a combo cordless phone/answering machine powered by AC to DC converter block. Input: 120v,
60hz, 8.5w. Output: 9vdc, 500ma.A low cost refurb UPS (APC BK280) has specs as follows:
Output power capacity 280 VA, 180 Watts Replacement battery cartridge RBC2 Typical backup time at half load 18.2 minutes Typical backup time at full load 6.7 minutes
On the assumption that the cordless phone's batteries are fully charged when a long outage begins, I'm thinking that even less than the indicated power would be drawn to keep the answering base alive until the phone's batteries get weak, a which point more power would be drawn for charging. The phone would not be used during an outage, so its NiCad batteries would discharge just from being idle.
What's your guesstimate of backup time running on UPS described above???
Thanks, Len