Bad battery causes no power even with utility power present?

[lstone19_apc]

I had an "interesting" problem yesterday. I have a number of APC UPSes in the house. This was a Back-UPS NS600 with the model code BN600 on the back (am I correct that NS600 is a generic model while the BN600 is more specific?). When I left the house, all way fine but less than two hours later (as I would subsequently determine the timeline), there was no power to the backed up outlets (don't know about the surge-only outlets) and the unit was emitting a constant tone that I've learned to associate with a failed battery.

I was surprised that a bad battery would cause no power even with utility power present. Is this the expected behavior for this model? I would have expected it to keep providing power so long as utility power was present.

As background of my setup, it powers a bunch of stuff in my home office including some of the comm. equipment for our Internet access. Since I run a home mail server (largely unattended), it's critical to the operation. The server itself is on an XS1500 (model code on the back is BX1500G). Should I expect the same behavior with the XS1500? Since the XS1500 is supposed to have a hot swappable battery, I'm hoping it will keep running fine with a bad battery (separate question to be posted about the battery for it).

[BillP]

Hi,

Yes, NS 600 is the "series" and BN600 is the model number we work with (thank you for providing it). A constant tone/beep with no power output could be a few things. It could be a failed battery where the UPS tried to transfer to battery during a power blip, the battery failed and it couldn't support the load, and then it sat like this.

But on the BN600, what specifically was connected to it? This behavior could also be an overload of the UPS.

For the most part, I think this behavior is the same across most Back-UPS though BX1500G is a line interactive model. I think in general, removing a battery from the UPS while it is online will continue allowing the UPS to provide output but the problem arises when the UPS wants to transfer to battery and it is dead or not present.

[lstone19_apc · Accepted solution]

Angela, thanks for the reply. I very much doubt it was an overload. The biggest draw on it is an external monitor (Apple Cinema Display) for my laptop (the laptop is not since its battery will keep it going long enough). Everything else is low power "power brick" devices - the DSL modem, two routers, USB hub, and an external disk drive. The monitor would have been asleep at the time so the draw should have been very small.

I removed the battery (which was warm) and replaced it with a new spare I keep on hand and all was fine. The UPS has a 2006 manufacture date per the serial number so although I may have replaced the battery once before (I started tracking replacements in 2011), age of the battery is a factor.

Also, I updated my configuration so the DSL modems and routers are now powered from the BX1500G so all my power needs for my server and Internet access are dependent on just the BX1550G.