Question : Problem: Smart-UPS 3000 XLM in self-test loop and failing under load.

I have a rack-mounted APC Smart-UPS 3000 XLM (product SUM3000RMXLI2U) with a single additional battery (SUM48RMXLBP2U).  Manufactured 12 months ago, commissioned 6 months ago.  Worked fine until a few days back.

At that time it suddenly started running self tests every few seconds (schedule is fortnightly).  It did 100+ over a one hour period (all reported successful) then declared a faulty battery. At the next self test (a few seconds later) it reported the faulty battery condition no longer existed.  This cycle of faulty battery / good battery continued at approx 15 sec intervals for about 20 minutes, at which point it reported a low battery, followed by a discharged battery.  A few seconds later it reported the low battery condition no longer existed.

It then started going through a repeated cycle of low battery / discharged battery / battery OK (about 10 times over a 6-minute period), finally reporting it was on battery power due to an input power problem, with output being turned off due to low battery 30 secs later.

The reporting of the input power problem seems to have coincided with the input power circuit (not on an RCD) tripping at the main board - I don't know whether the UPS caused the circuit to trip or whether, coincidentally, sometrhing else tripped the circuit and this caused the loss of power to the UPS.  However the UPS is the only device on this circuit ( which is not protected by a RCD).

I re-set the circuit then tried re-starting the UPS, initially with no load but gradually building up the load.  It caused the main circuit to trip again once partially loaded (only to under 50% capacity).  I cannot identify any specific load causing the tripping (it is not repeatable).

Running the UPS with no load at all I find that it is runing a successful self-test every 15-20 seconds.  I've not dared load it with anything since.

Any ideas?  

Nigel

Answer : Problem: Smart-UPS 3000 XLM in self-test loop and failing under load.

Give APC a call, by default there is a 3 year warranty (I believe) on the unit if the battery or the unit itself is faulty they will replace it free of charge