External batteries on an APC RS1500 UPS (BR1500)?

Hi,

Has anyone tried plugging external lead-acid batteries to the APC
RS1500 UPS (model number BR1500)?

This unit has an external connector to connect the BR24BP external
battery back. However, the battery pack is expensive, and I was
wondering whether it is possible to connect a set of the batteries
that are found inside the BR1500 to this connection instead.
Compatible non-APC-branded batteries are available for around $40,
which is a lot better than the $150 that Amazon.com is charging for
the BR24BP.

Does anyone have a copy of the service manual for either of these
units? Can anyone verify if there is any electronics in the BR24BP,
or whether it contains only a set of batteries?

Thanks for any help!

On Fri, 09 Nov 2007 14:09:22 -0800, tim_s_moore@yahoo.com
wrote:

>Hi,
>
>Has anyone tried plugging external lead-acid batteries to the APC
>RS1500 UPS (model number BR1500)?
>
>This unit has an external connector to connect the BR24BP external
>battery back. However, the battery pack is expensive, and I was
>wondering whether it is possible to connect a set of the batteries
>that are found inside the BR1500 to this connection instead.
>Compatible non-APC-branded batteries are available for around $40,
>which is a lot better than the $150 that Amazon.com is charging for
>the BR24BP.
>
>Does anyone have a copy of the service manual for either of these
>units? Can anyone verify if there is any electronics in the BR24BP,
>or whether it contains only a set of batteries?
>
>Thanks for any help!


I've not seen this model in person but will put a few
thoughts out there...

The primary battery appears to use only 3 pin connection
which would be positive, negative, and current sensing. The
external battery is the same, does not appear to have
electronics in the external battery pack but whatever you
use would need to have the same connector or you'd have to
add the connector yourself.

It appears to use a pair of 12V cells in series for 24V, you
could use whichever you find more economical except if the
total capacity is not the same it might throw off the
software which IIRC, estimates runtime and battery health.
For example if you set the UPS to run until there was only 5
minutes of battery life remaining and that calculation the
UPS makes is based on a different cell capacity, the result
probably won't be an accurate calculation. Likewise with
charging, if you were to use a significantly larger pair of
batteries, for example a couple of deep cycle marine
batteries, the UPS might be programmed to conclude there is
a problem in that the battery pack did not fully charge
within the expected interval, or it might have a timer
shutoff from normal to float charging so it took quite a
long time until the battery pack was up to full charge
again.

If the compatible non-APC pack is $40 I don't understand
what you're asking, since by definition "compatible" should
mean they'll work... but are they compatible replacements or
compatible as-in identical? If only a replacement that is
just the batteries themselves and you are expected to reuse
the APC connector from the original pack, then you still
won't have the 2nd connector you need for the external pack.

> I've not seen this model in person but will put a few
> thoughts out there...
>
> The primary battery appears to use only 3 pin connection
> which would be positive, negative, and current sensing. The
> external battery is the same, does not appear to have
> electronics in the external battery pack but whatever you
> use would need to have the same connector or you'd have to
> add the connector yourself.
>
> It appears to use a pair of 12V cells in series for 24V, you
> could use whichever you find more economical except if the
> total capacity is not the same it might throw off the
> software which IIRC, estimates runtime and battery health.
> For example if you set the UPS to run until there was only 5
> minutes of battery life remaining and that calculation the
> UPS makes is based on a different cell capacity, the result
> probably won't be an accurate calculation. Likewise with
> charging, if you were to use a significantly larger pair of
> batteries, for example a couple of deep cycle marine
> batteries, the UPS might be programmed to conclude there is
> a problem in that the battery pack did not fully charge
> within the expected interval, or it might have a timer
> shutoff from normal to float charging so it took quite a
> long time until the battery pack was up to full charge
> again.
>
> If the compatible non-APCpack is $40 I don't understand
> what you're asking, since by definition "compatible" should
> mean they'll work... but are they compatible replacements or
> compatible as-in identical? If only a replacement that is
> just the batteries themselves and you are expected to reuse
> theAPCconnector from the original pack, then you still
> won't have the 2nd connector you need for the external pack.- Hide quoted text -
>

Hi,

Thanks for the response.

By compatible batteries I meant compatible replacements for the two
12V batteries that are found inside the RS1500 main unit (http://
www.refurbups.com/Back-UPS-1500-RS-SX-Batteries). The BR24BP is case
which houses the expansion batteries, which presumably and hopefully
are the exact same batteries that are found inside the RS1500, with no
additional electronics. That would make the case worth around $110
(nearly 3 times the cost of the batteries!), and since the UPS is
hidden under my desk it's an unnecessary expense... The technical
spec of the RS1500 does not provide the capacity of the batteries, but
the spec of the BR24P states that it's capacity is 372 Volt-Amp-
Hours. It seems to more than double the run-time of the RS1500, so
they could be higher capacity than the RS1500 batteries.

So, you are right that the software could miscalculate the run-time.
Not so much of a problem, so long as I know. I just dont want to blow
the thing up! Since the compatible batteries don't seem to come with
the connector I might have to buy the branded batteries as they do.
The internal and external connectors seem to be the same at least.

Thanks again for your insights. If anyone has any direct experience
of this then please let me know!

On Mon, 12 Nov 2007 14:26:40 -0800, tim_s_moore@yahoo.com
wrote:

>> If the compatible non-APCpack is $40 I don't understand
>> what you're asking, since by definition "compatible" should
>> mean they'll work... but are they compatible replacements or
>> compatible as-in identical? If only a replacement that is
>> just the batteries themselves and you are expected to reuse
>> theAPCconnector from the original pack, then you still
>> won't have the 2nd connector you need for the external pack.- Hide quoted text -
>>
>
>Hi,
>
>Thanks for the response.
>
>By compatible batteries I meant compatible replacements for the two
>12V batteries that are found inside the RS1500 main unit (http://
>www.refurbups.com/Back-UPS-1500-RS-SX-Batteries).


These look like just a pair of standard 12V 7AH SLA cells,
not the connector wiring you'll need even if you can accept
leaving them loose next to the UPS or in a box.


>The BR24BP is case
>which houses the expansion batteries, which presumably and hopefully
>are the exact same batteries that are found inside the RS1500, with no
>additional electronics.

What is the additional runtime claimed by adding this
BR24BP? If it doesn't double the runtime but rather a
higher increase in runtime, it would suggest BR24BP uses
higher capacity cells. Unless they just wanted to make the
BR24P identically sized for rackmount purposes, it also
seems they ought to put larger cells in it to account for
the size and higher cost.



>That would make the case worth around $110
>(nearly 3 times the cost of the batteries!), and since the UPS is
>hidden under my desk it's an unnecessary expense... The technical
>spec of the RS1500 does not provide the capacity of the batteries, but
>the spec of the BR24P states that it's capacity is 372 Volt-Amp-
>Hours. It seems to more than double the run-time of the RS1500, so
>they could be higher capacity than the RS1500 batteries.

372 VAH / (12V battery *2 ) = 15.5AH / battery
A couple of the following might be a good substitute, but
you still need the connector and wiring.
http://www.batterywholesale.com/batt...tml?prodID=377

>
>So, you are right that the software could miscalculate the run-time.
>Not so much of a problem, so long as I know. I just dont want to blow
>the thing up! Since the compatible batteries don't seem to come with
>the connector I might have to buy the branded batteries as they do.
>The internal and external connectors seem to be the same at least.
>
>Thanks again for your insights. If anyone has any direct experience
>of this then please let me know!

I don't know if the connector is truely proprietary or just
unusual, if you felt like spending the time you could wade
through a Digikey.com, Newark.com, Mouser.com online or
website catalog, or you could contact APC to see if they'll
sell the connector.

You might also see if you can find someone on ebay selling
either pack since they seem to have the same connector, then
use whatever batteries you want, noting to which pins of
the connector the batteries are wired.

There might be another option if you're handy with a
soldering iron. Since it seems less important that the
internal pack has a quick-disconnect connector, you could
take the connector and wiring from the internal pack and use
on an external pack, then permanently solder in leads for
the internal pack, bypassing the proprietary connector
entirely or dremeling out the plastic and soldering direct
to the connector contacts, then the other end of the leads
would just need the standard battery connectors which can be
found many places at fairly low cost.