ro0ter
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Hi everyone,
I got an APC unit (APC Back-UPS CS 650 BK650EI) from a friend for a symbolic price, as he bought new UPS units for his internet club, more powerful ones. The UPS-es were not used for more than 2 years, I bet that he still has the warranty papers somewhere in his company drawers (whatever, I don`t count on that). The power line at my friend`s net cafe is very good, still, sometimes there were power failures (wind storms, thunder storms or simply someone sticking his fingers in the wall outlet/power cord therefore leaving the entire building in blackout for a couple of minutes). I can say that it was actually used for less than 1%-2% of its running time, at most 10 discharges of the battery, but let`s say 20; battery is not the problem.
Although I got my ups almost as a present (a couple of beers), I still wanted to test it so that I know whether to count on it or not and - if I can count on it - how much for, as I can change it if it has any problem (there still are some ups-es in his storage which I can exchange this one for). Everything was fine, the UPS was charging its battery, nothing to worry about. In the meantime I gave it a short "able to backup PC and LCD load test" which it passed (PC and LCD were backed up for ~2 minutes), I decided it`s better to test the full backup period with the battery fully charged. I therefore left it over night to charge so that I could test the maximum battery backup time the next day (Saturday, that is yesterday). The next day (Saturday), I woke up and went to grab a glass of water but my thirst went away when I passed by the door of the room where the UPS was lying. I heard a very loud intermittent whistling sound and went to see what`s this all about. There was absolutely no load on the UPS, it only was connected to the mains to charge its battery. The second I disconnected it from the mains the squeaky sound faded away. That seemed strange enough so I went to kill my thirst with some water.
Anyway, I conducted the backup test as planned and it was able to back up my PC (intel e8400, 3hdds, 1 x radeon 4850hd; thermaltake tr2 500w) and 17" LCD (~60w) at approximately half load (World Community Grid recycling any unused CPU + some browsing + a couple of rounds in TM Nations in 1080p) for 10 minutes. After 10 minutes the UPS started beeping continuously (low battery, it was usually beeping 4 times and a long pause when it backed up the devices behind it with battery at a good level) so I plugged the mains back in. I left it to charge again. There intermittent squeaky sound was no more (while charging).
Finally, after it charged, the squeaky sound was present again, therefore I opened it to see what is it made of and I gave it a run without any cover (connected battery, power cable). The respective sound comes from the transistor (Q10) next to the tall transformer. It should be some PWM which is out of sync. I don`t own an oscilloscope or other advanced electronics equipment to check what is the component that oscillates out of sync and what is the frequency it should have (when there is no sound).
Bottomline:
I would like to know whether there is any solution to the problem or not, and there is, what would that solution be. I know that most of these APCs are whistling a lot when idle, but is there nothing that we can do about it? Is there no engineer that works at APC to give us a hint?
Thank you and best regards,
ro0ter
I got an APC unit (APC Back-UPS CS 650 BK650EI) from a friend for a symbolic price, as he bought new UPS units for his internet club, more powerful ones. The UPS-es were not used for more than 2 years, I bet that he still has the warranty papers somewhere in his company drawers (whatever, I don`t count on that). The power line at my friend`s net cafe is very good, still, sometimes there were power failures (wind storms, thunder storms or simply someone sticking his fingers in the wall outlet/power cord therefore leaving the entire building in blackout for a couple of minutes). I can say that it was actually used for less than 1%-2% of its running time, at most 10 discharges of the battery, but let`s say 20; battery is not the problem.
Although I got my ups almost as a present (a couple of beers), I still wanted to test it so that I know whether to count on it or not and - if I can count on it - how much for, as I can change it if it has any problem (there still are some ups-es in his storage which I can exchange this one for). Everything was fine, the UPS was charging its battery, nothing to worry about. In the meantime I gave it a short "able to backup PC and LCD load test" which it passed (PC and LCD were backed up for ~2 minutes), I decided it`s better to test the full backup period with the battery fully charged. I therefore left it over night to charge so that I could test the maximum battery backup time the next day (Saturday, that is yesterday). The next day (Saturday), I woke up and went to grab a glass of water but my thirst went away when I passed by the door of the room where the UPS was lying. I heard a very loud intermittent whistling sound and went to see what`s this all about. There was absolutely no load on the UPS, it only was connected to the mains to charge its battery. The second I disconnected it from the mains the squeaky sound faded away. That seemed strange enough so I went to kill my thirst with some water.
Anyway, I conducted the backup test as planned and it was able to back up my PC (intel e8400, 3hdds, 1 x radeon 4850hd; thermaltake tr2 500w) and 17" LCD (~60w) at approximately half load (World Community Grid recycling any unused CPU + some browsing + a couple of rounds in TM Nations in 1080p) for 10 minutes. After 10 minutes the UPS started beeping continuously (low battery, it was usually beeping 4 times and a long pause when it backed up the devices behind it with battery at a good level) so I plugged the mains back in. I left it to charge again. There intermittent squeaky sound was no more (while charging).
Finally, after it charged, the squeaky sound was present again, therefore I opened it to see what is it made of and I gave it a run without any cover (connected battery, power cable). The respective sound comes from the transistor (Q10) next to the tall transformer. It should be some PWM which is out of sync. I don`t own an oscilloscope or other advanced electronics equipment to check what is the component that oscillates out of sync and what is the frequency it should have (when there is no sound).
Bottomline:
- UPS works flawlessly
- battery is in VERY GOOD shape
- normal buzzing (50hz) sound when inverter is running, fair enough
- no sound while charging battery (excellent, I`m impressed)
- abnormal ugly intermittent whistling squeaky sound when ups plugged in (power on the mains is ok) and battery fully charged (with/without consumers, won`t matter as they are directly connected to the network)
I would like to know whether there is any solution to the problem or not, and there is, what would that solution be. I know that most of these APCs are whistling a lot when idle, but is there nothing that we can do about it? Is there no engineer that works at APC to give us a hint?
Thank you and best regards,
ro0ter
