[Tfug] FTGH: APC Back-UPS Pro 650

[Bexley Hall]

--- Sean Warburton <hl2addict at gmail.com> wrote:

> The unist says XS 1000, but it seems that it was
> replaced by the RS series.
>
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=BR1000
> That
> looks EXACTLY like that I have. The batteries are

The BackUPS Pro 650 takes an "RBC4" battery.
12V at 12AH IIRC.

>From the image (above), the RBC32 looks to be a pair
batteries (hence, a "battery"!  :> ).  Whether each
of these is compatible BY ITSELF is unknown.

I should just pull the battery and read the P/N off
of it, etc.


> Exide Powersafe sealed
> lead acid batteries. There are two of them (in the
> backup, they were
> togeather...in parallel (I think? where the current
> lasts longer than one
> battery, as opposed to in series, which yields more
> current/voltage,

You almost always wire batteries (and the "cells"
therein) in series.  Wiring in parallel causes
one bad "battery" (string-of-cells) to drag down
the "good" battery (other string-of-cells).

It also complicates charging as each battery's
chemistry may have different instantaneous needs
and the charger can't ensure that "both" (or more!)
are charged to the same state, etc.

You also wire them in series because the losses in
the switching transistors (FETs nowadays) are less
of a factor.  E.g., if you "drop" (lose) half a volt
(or more!) across the switching transistors and you
are working from a nominal 12V DC supply, then you
have thrown away 4% of your input voltage to the
switching transformer.  I.e., instead of having
12V at the transformer, you have 11.5.  So, for a
given output *load* (at the secondary of the switching
transformer), you need more amperage from the battery.

Yet, the battery is still delivering 12V -- *it*
doesn't know that 0.5V of that is being "lost".
So, the battery doesn't last as long.

And, since the current from the battery is increased,
the losses in the switching transistors are also
increased!  At the very least, resulting in more
power being dissipated therein (and more *heat*!)

> right?). The battery also says EP 1229W. Here it is:
> http://batterysupplyco.com/xs1000.html Except for
> the white stickers...Think
> they will work?

I'll have a peek at the battery in the UPS tonight
and compare...

--don
 


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