UPS External Battery

[BeeJ]

I have several UPS units. One has a connector for an external 12V
battery. I am thinking of hooking up a deep discharge marine battery
to the UPS. Is there any thing to watch out for? What current rating
wiring should I use? The biggest UPS is 900VA.
Also, can a connector mate be found or should I just solder or attach a
lug to the contacts?
Suggestions please.

The UPS is signaling to the PC that I should replace the battery but
running the built in test says it is still viable but probably not for
a long power outage. I only want the UPS to fend off power line
hickups.

[Lawrence Statton]

BeeJ <nos...@spamnot.com> writes:

> I have several UPS units. One has a connector for an external 12V
> battery. I am thinking of hooking up a deep discharge marine battery
> to the UPS. Is there any thing to watch out for?

Yes. Many cheap UPS units are designed to run, when at maximum load,
the switching transistors at the ragged edge of their peformance, or
even above, knowing that the battery is going to die in a few minutes.
If you put a battery tha can handle maximum load for much more time
than was originally anticipated (e.g. replacing an internal 7Ah SLA
with a large 100Ah flooded cell), then the transistors can easily cook
themselves the first time you have an outage.

> What current rating
> wiring should I use? The biggest UPS is 900VA.

If the output is 900VA, and we assume a terminal voltage of 12.5
volts, then the current is going to be (900/12.5)*(1/efficiency).
Your absolute BEST bet would be to hook up a "about the middle" load
(say a few incandescent lamps) and measure the voltage and current
from the actual battery, and get a good ballpark guess for the
efficiency. Add a safe margin and engineer for that amount of
current. My wild-ass-guess: you are unlikely to draw more than 100
amps at 12V for the 900VA unit.

> Also, can a connector mate be found or should I just solder or attach
> a lug to the contacts?

A very common connector for that application is the Anderson
"Power-Pole" series connector. Here's a web-page that shows them
being used in an amateur radio context:

http://www.westmountainradio.com/content.php?page=supportrr

A google-search will lead you to mail-order sites where you can get
the connectors onesey-twosey.

> Suggestions please.
>
> The UPS is signaling to the PC that I should replace the battery but
> running the built in test says it is still viable but probably not for
> a long power outage. I only want the UPS to fend off power line
> hickups.

If you really do only need "few tens of seconds", I vigorously
recommend just replacing the internal battery with the same
size-and-chemistry. No power-connector or pass-transistor headaches.

A guy at a local flea-market sells "dead battery" APC 600VA units for
$40 bucks, and I can buy a brand-new battery at a jobber downtown for
another $20. These just have a YUASA 7Ah SLA in them. The larger
units often will go to a 14Ah or 25Ah battery, which will cost more.

Here is a pic of one of the APC units that I have six of now:

http://www.kaboodle.com/hi/img/b/0/0/158/e/AAAAC8SRwKgAAAAAAVjr1w.jpg

(just a random image I found off the web - no relation to Kaboodle)

--
NK1G - Lawrence
echo 'lawre...@abaluon.abaom' | sed s/aba/c/g

[Jeff Liebermann]

On Wed, 15 May 2013 13:21:47 -0700, BeeJ <nos...@spamnot.com> wrote:

>I have several UPS units. One has a connector for an external 12V
>battery.

Could I trouble you to disclose the maker and model number of the UPS
with the connector? It might then be possible to search the
manufacturers archives for information on attaching an external
battery, such as does the internal battery need to first be
disconnected.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Martin Riddle]

"BeeJ" <nos...@spamnot.com> wrote in message
news:kn0qhl$c0n$1...@dont-email.me...

That�s probably the 5 year alarm for battery replacement. Which is about
how long they last on a float charge.

Measure up the battery and go to Mouser and get a CSB replacement. It's
less expensive that what APC or triplite will
charge you and will last just as long.

And you don't have to worry about charging a larger battery which has
its own set of problems.

Cheers

[BeeJ]

After serious thinking Jeff Liebermann wrote :

> On Wed, 15 May 2013 13:21:47 -0700, BeeJ <nos...@spamnot.com> wrote:
>
>> I have several UPS units. One has a connector for an external 12V
>> battery.
>
> Could I trouble you to disclose the maker and model number of the UPS
> with the connector? It might then be possible to search the
> manufacturers archives for information on attaching an external
> battery, such as does the internal battery need to first be
> disconnected.

The two UPS units are:
APC BX900
APC XS1500 (label on this unit says battery pack BR24BP)

[Jeff Liebermann]

On Wed, 15 May 2013 20:05:30 -0700, BeeJ <nos...@spamnot.com> wrote:

>After serious thinking Jeff Liebermann wrote :
>> On Wed, 15 May 2013 13:21:47 -0700, BeeJ <nos...@spamnot.com> wrote:
>>
>>> I have several UPS units. One has a connector for an external 12V
>>> battery.
>>
>> Could I trouble you to disclose the maker and model number of the UPS
>> with the connector? It might then be possible to search the
>> manufacturers archives for information on attaching an external
>> battery, such as does the internal battery need to first be
>> disconnected.

>The two UPS units are:
>APC BX900

<https://www.apcc.com/products/resource/include/techspec_index.cfm?base_sku=BX900>

No external battery connector on the rear panel. Therefore, no
official method of adding an external battery. Nothing in the user
manual on attaching an external battery.

>APC XS1500 (label on this unit says battery pack BR24BP)

There's a bit of a muddle here. APC rebranded an older unit, that was
labeled XS1500 as the BX1500, but still lists is at XS1500. Worse,
APC also has two different XS 1500 models for the BackUPS and SmartUPS
series of products. So, rather than muddle though this mess, could I
trouble you to provide the full model number, or a URL with a photo of
the actual unit, which should eventually lead to the user manual,
which should have instructions on how to attach the external BR24BP
battery pack? My guess(tm) is that you're trying to do something like
this:
<http://www.amazon.com/APC-BR24BP-BACK-UPS-1500VA-Battery/dp/B00009Q97G>

I couldn't find the original BR24BP manual on the APC web pile.
However, I did find this destruction manual on how to break it open
and tear it apart:
<http://www.yourwarrantyisvoid.com/2009/10/27/breaking-into-apcs-br24bp-battery-pack/>
Note that the external battery pack consists of 4ea 12V batteries,
arranged in a 2x2 24V system. I've had rather bad luck with a similar
arrangement in the APC SmartUPS 1400, which killed batteries (due to
current hogging) at an alarming rate. Photo of some of the 30 odd
units being scrapped and on the way to the recycler:
<http://802.11junk.com/jeffl/pics/home/slides/apc1400.html>
Don't parallel batteries if you have other options.

Incidentally, I have a similar BackUPS XS1000 in my office. It's
major claim to fame is that it kills a battery pack every 4 years. I
think it's on its 3rd set of batteries now, and is probably due for
another battery transplant.