[rescue] Powerware UPS?

Scott Newell rescue at sunhelp.org
Mon Oct 15 15:53:19 CDT 2001


>It's not the load you put on it, it the load it will put on your electrical 
>system.

To a point, yes...


>If you have nothing more than a 100 watt bulb plugged into it, it will run 
>for a long time, but when power is restored, it will PULL LIKE HELL 
>recharging the batteries.

Supposed to charge to 80% in 2 hours, and it has 48V of batteries at 9AH.
Let's assume it can fully charge dead batts in 1 hour, and assume that the
power supply is less than 50% efficient.  9A from the wall just to charge
batts is a big load, but not too bad.  

Look at it another way: it's rated at 2kVA output, so that's about 16.67 A
(assuming 120V line).  If the input cord and plug is rated at 20A, that
only leaves about 3.3A to charge batteries (and heat the room).  Right?
After all, if you've got a fully loaded system, it's got to supply output
power _and_ charge the batts without exceding the 20A (input) rating. 

This just in--Powerware claims minimal current drain to charge
batteries--2A or less.


newell




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