UPS Backup Time Guesstimate

What's your guesstimate of backup time running on UPS described above???

You can't get there from here. The PSU essentially zero load. The UPS will probably have 10-20% of its maximum load as waste power.

So, take the uptime as 5-10 times the 'full load' value. and add on 20% as the battery will be more efficient. However, I wouldn't bother. I'd take 6 D cells, which will output 9V, then add a diode in series with both the PSU output and the D cells. The batteries will automatically take over when the PSU fails. (depending on the exact voltage of the PSU, the batteries may drain a little. However, you should still get well over 10 hours of uptime, more likely

Just over an hour maybe ?

Graham

Hmmm... that's the rating of the wall wart - *NOT* the phone !

In which case the UPS will likely run about as long as it does with no load at all. Whatever that is.

Graham

Same as the one I gave on Tuesday:

Since this involves rechargeable batteries, all "marketing" numbers can be halved, making the half load number something like 9 minutes. The phone's power supply takes 8.5 W, so you'd expect something like (90 W /

Matt Roberds

You need to re-think this:

"The phone would not be used during an outage". So why do you need a backup? Imagined response: "Well, the phone might ring, in which case it would be used."

Charging the handset is simply not a factor - unless, as I suspect you will find if you get a long outage, that the "non-use" is bullshit. I think what actually may happen is that the phone will get more use during an extended outage than usual.

Just buy a corded phone or use Ian's idea.

Ed

Ed,

One other possibility, and the only one I'm actually trying to deal with, viz., calling in from elsewhere to retrieve messages on answering machine. Phones, as you know, often operate in a power outgage. An additional issue with this machine is that its message day and time stamp become inaccurate after even a brief power blip.

Len

when

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batteries

phone

discharge