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Posted: 2023-05-2903:00 AM
SMART-UPS SUA 750i - incorrect current load readings
I have Smart-Ups SUA750i and recently discovered that it has some problems with working correctly.
Long story short - it laid down at balcony for a few years, and i decided to sell it since i already have another exact one. Also spare money is plus in my situation.
After revealing my plan to father he immediately insisted on changing capacitors (which is logical move, because i already changed them in my second UPS), but not for standard electrolytic, but for tantalum ones.
Some time later plan was successfully (probably) completed (P.S. not all of capacitors have been replaced for tantalum ones, few of them was replaced with new electrolytic).
Next thing is to test UPS if it works as intended. Everything seems to work well - stable input/output, switching to batteries and back, boosting, (cant check trim mode since i dont have equipment for that), connection via usb and com ports.
As title mentions, only thing is not working properly is current load reporting. And i mean that neither LEDs on front panel, which are responsible for indicating current load, nor software in Linux (apcups demon, latest version) and Windows 10 (Powerchute Business edition 9.5), dosent report proper load readings.
I came to this conclusion by simply connecting same wattage load to both normal and faulty UPS's. U can see the exact numbers on attached pictures.
Thing that should be mentioned is that i can not neither 100% confirm, nor 100% refute fact, that before the capacitors have been changed, load readings and indication at faulty UPS was proper.
In the conclusion i suspect that something on electrical side does not work correctly. Probably something with UPS CPU, i mean EEPROM or something (but i dont wont to think about it). I would highly appreciate your thoughts on problem. Stay safe and have a wonderful day!