Can I plug an external battery in a BR1500G?

[Anonymous user]

I had an old Back-UPS XS 1500 that just failed.  Trouble is, I put the third or fourth new battery pack in it just months ago - meaning I have a good pair of 12V batteries ganged together.

Since this unit served me for way over a decade, which I consider very good for any piece of electronic gear, I have just ordered a new APC BR1500G Back-UPS Pro.

The Back-UPS Pro of course has a port for an external battery connector, just as my old unit did, and this appears compatible with the connector on the battery-pair packs.

Can I just take the perfectly good batteries out of the old unit and plug the pack into the slot in the new unit?

Or is there a hard requirement to use the (seemingly overpriced) BR24BP external battery pack?

Am I missing something fundamental here about why a box that holds two pairs of batteries should cost $170?

-Noel

[Anonymous user]

The safest thing to do might be to pick up a used but working Back-UPS XS1500.

That said, yes, I believe it should be possible. I believe the pinout is identical between the units, though you'll want to verify that with a multimeter. You'd definitely want to create some kind of enclosure for the batteries, made out of a rugged material that won't burn or be affected by possible acid leakage if the batteries overcharge. Whatever you come up with must not have an airtight seal. Sprinkling some baking soda in the bottom of whatever you use would help to contain any acid spills.

Caveat: The older XS 1500 claims its battery circuit isn't isolated from the AC power line (and it appears not to be). If the same is true of the BR1500G, it would best not to do this -- or if you must, to be absolutely certain no one can ever come into contact with any battery terminal or wiring. That would be one reason why the enclosure would be essential. Maybe you can find an empty one somewhere? (Although the enclosure carries four batteries instead of two.)

Disclaimers: You and you alone are responsible for the results of your actions, good or bad. I'm not affiliated with APC or Schneider Electric and neither one approves of or endorses anything I post. Attaching a self built battery pack may very well void the warranty coverage on your BR1500G.

[Anonymous user]

Thank you, William.

I'm an engineer, please rest assured I'll create the proper environment for safety.

I'll post feedback when I get everything together.

-Noel

[Anonymous user]

Sounds good. Management of this discussion board seems to be pretty easy going, though I certainly want to stay on their good side and out of trouble.

I'd certainly like to hear how your efforts turn out. I'd have probably tried it myself, were it not for the BX1500G's lacking an external battery connector.

For whatever it might be worth, I have a Back-UPS XS 1500 that stopped working reliably several years ago. Troubleshooting it revealed an intermittent KA7812 linear regulator to be the problem. It's a surface mounted D-Pak part and I'd guess it conked out due to the large voltage drop (24-27VDC input). This kills power to the microcontroller.

[Anonymous user]

Thank you for your candor and suggestions, William.

Mine didn't fail quite in the same way as yours.

A few months ago it started switching to backup on and off, as though it had become more sensitive to line problems, and at that time changing the sensitivity from medium to low (via PowerChute) corrected that behavior.  It ran thereafter, successfully switching to battery on several actual (short) line outages.  A few days ago it just switched to backup and wouldn't believe that there was line power, even though the controller would indicate (again, via PowerChute) that line voltage was good.  I'm guessing whatever circuitry detects quick line dropouts has failed in a way that makes it believe that there are a constant stream of small outages - but that's no more than intuition.

Unless there are two separate controllers that talk to the host computer and monitor power, the microcontroller still seems alive and functional, since it does talk to the computer.

The only other thing that it's doing that's odd is that (removed from service and with no load) it cycles some relays near the top of the unit inside repeatedly from none to about six times when I power it on.

That this is the second incident where it is showing signs of flakiness is why I'm replacing the whole unit.  It's served me well.

I haven't taken it apart to look at the specifics yet.

-Noel

[Anonymous user]

Yep, that sounds familiar. I've got another Back-UPS RS 1500 that started doing similar things about a year ago. When cold it won't even switch to line power. As it warms up, it gradually begins to operate correctly, cycling less and less until it stays on line power. I too have set the sensitivity to low on that unit as a workaround.

I have yet to look into why it might be doing so. I suspect an issue with capacitors having drifted out of tolerance, possibly leading to noise being introduced on the line monitoring ADC's power input. My line voltage is a bit high, but even sticking a variable autotransformer between the UPS and the outlet as a test did not help.

It'd be nice if APC made service literature or schematics available for purchase, for those of us who are capable of working on these units safely.

[Anonymous user]

If you have a RS1500 which isn't good anymore, I'd love to buy the female socket harness assembly Part #870-1953A.  This is the (grey plastic) female connector harness which remains in the battery compartment after disconnecting the male connector and removing the battery pack.

[Anonymous user]

Hi Alain,

It's an XS, not RS, but it does have that connector.  First I want to make sure I can't just resurrect the thing with something simple, such as a capacitor replacement.  If I do choose to "part the thing out", besides transferring the relatively new batteries to my new one I'll keep your request in mind for the connector.

I have the new BR1500G Back-UPS Pro now in service and it went in as a replacement as painlessly as can be.  I had already had the PowerChute software up to date, so it was literally a "plug everything in and go" replacement.

My only complaint is that APC doesn't sell the "good models" like this BR1500G Pro through local brick and mortar shops like Best Buy or similar.  As a home-office user I'd have paid a retail premium to have been able to replace my failed unit immediately.  As it was, Amazon Prime had it here in 4 days (Thursday to Monday) and we DID have a storm blow through that COULD have affected the line power.  I was fortunate that it didn't.

The only other thing that's caught my notice so far is that there was a slight smell of "warm electronics" initially from the new unit, though literally nothing got more than slightly warm to the touch externally.  The smell is virtually gone today (the second day of service). 

Ultimately this new Back-UPS Pro model must be somewhat more efficient, because it shows 14 minutes of available backup time and the old one only ever claimed 11.  I have tested it, though not for the full duration.  I hope that's not just APC Marketing influencing a more optimistic estimate!

-Noel

[Anonymous user · Accepted solution]

On 1/26/2016 9:49 AM, Alain said:

If you have a RS1500 which isn't good anymore, I'd love to buy the female socket harness assembly Part #870-1953A.  This is the (grey plastic) female connector harness which remains in the battery compartment after disconnecting the male connector and removing the battery pack.

I plan to repair my RS1500 when I've got the time, otherwise I'd be willing to do this. The XS variant is almost exactly the same unit, I think it is lacking only the external connector for an add-on battery pack. I have examples of both and tend to refer to them interchangeably.

I'd be a little surprised if this weren't some sort of standardized connector. Perhaps some of the third party companies that sell pre-wired replacement battery packs compatible with APC UPS models could help?