I have a smart UPS 2200 that is giving me problems, I suspect that the batteries need to be replaced, but I am not sure. There are no visible problems, ie. no error codes, no error lights etc, but every once in a while, usually if there is a power "event", i.e. not a full blackout, but a spike or a low, the unit will begin to click, lights flash etc, and it will go one for a long time, usually ending with the power going out and everything getting turned off - even though, in fact, the power never actually went out - and none of the non-protected devices even shut down.
Of course my first guess is that the batteries need replacing, but at $350 for a new set, I don't want to get new batteries, only to find out that it is the unit itself...
Question is, what are the usual symptoms for bad batteries? and/or how do I know for sure if that will solve the problem.
If I'm not mistaken APC will actually provide support for the unit in the sense that one of their support engineers will help diagnose the problem based on the symptoms. I've used their "Chat Now" support feature for several UPS units that have long been out of support.
http://www.apc.com/support/index.cfm
In my experience, a bad battery is usually detected by the UPS itself and it beeps on a regular basis until it either drives you insane, or you replace the battery. Is the unit under support from APC?
The first step would be to do a battery test to see if the batteries could take a load. If that works fine, that the UPS is definitely bad. If the problem occurs again, then it could be either the UPS or battery. You would have to decide between replacing the battery, obtaining support from APC or just replacing the whole unit.
I have seen bad batteries not be detected by the UPS, but the result is always a complete outage when the input power fails.
It's hard to tell from your description, but this almost sounds like the unit going into a continual self-test loop. The biggest problem with the self-test is that it puts the batteries online for a short-time - so if the unit continually self-tests, the batteries are continually drained until there is no more battery power left.
It also means that the unit will not be able to charge the batteries because it is draining them as fast or faster than it can charge them.
I've seen two UPS 2200 RM units do this already. I don't know the root cause.