--- In [email protected], "Tedd Doda" <[EMAIL PROTECTED]>
wrote:
> On Sun, 23 Jan 2005 18:37:42 -0000, Coy Hilton wrote:
>
> >Yep my Best Power UPS is the largest that they build that runs
off
> >13.8 volts it's a 1.4 KVA.
>
> Hang on.....say you have a 1000 watt load on the UPS, that
> means you have about 72.5A running from the battery(s) to
> the UPS. Hope you have real big wires.
I don't know where you got 72.5 amps. I'm not saying it's right or
wrong.
That's only about 11.6 amps at 120 volts
The Best Power 1.4 KVA UPS is a FERO UPS and yes it has #4 or #6
Cable running from the BATTERY to the BUS, about 18 inches.
>
> >I have a question, How long does the 4 33AH batteries last at
what
> >ever load that you have connected, and is it a fairly light load?
It
> >seems that they wouldn't last long with much of a load.
>
> 48 volts times 33Ah gives about 1584 Watt/Hrs of energy.
> Theoretically, you could run a 1.5KW load for an hour, 750
> watt load for 2 hours, etc., but due to efficiency, it will
> be slightly lower.
I'm sorry to disagree but it's not likely that you get much more
than about 50% efficency and gell cells don't like being discharged
at their amp/hour rating most like a 10 hour rate or a 20 hour rate
much deviation from that will cause a drastic reduction in ratings.
In thery you might get 792 watts for an hour if your batteries are
rated for discharge over a 1 hour period It's more likely that you
will get between 528 and about 700 watts.
>
> Just to give you an example of run time, I had my hydro
> panel upgraded from the old fuses to a breaker panel. The
> electrician started at about 6PM, and it got dark about
> 8PM (late Fall). At 8PM he was half done and was trying to
> work with a flashlight. I suggested we take the feed going
> to the bank of 12 florescent lights and plug it into the
> UPS. He agreed and after 1-1/2 hours later, he finished
> the job and the lights were still going strong. The lights
> take about 380 watts (12 x 32 watt bulbs).
That's only 570 watt/hours
It's not likely your ballast are 100% efficient. It was more likely
about 680 watts. You were likely very close to being discharged
>
> One thing you have be careful when running florescent bulbs
> is that they usually don't like running from a modified
> square wave (the output of many of the low cost UPS's).
It's more likely that it's the ballast that don't like square wave
input because of the transformer. But with the new electronic
ballast that are more like a switching power supply, it schouldn't
care
> The Alpha unit has a monstrous output transformer that
> creates a true sine wave output (in part, that's why this
> thing is so heavy).
>
>
>
> Tedd Doda, VE3TJD
>
> Lazer Audio and Electronics
> Baden, Ontario, Canada
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