Does charge level affect transfer time?

[Parthu1708]

My new PC has got a Corsair HX1000i PSU connected to a APC Smart-UPS SUA1500I-IND pure sinewave UPS.

I was running a OCCT Power Test (that pushes CPU & GPU simultaneously) and I manually shut down the switch on the wall socket that the UPS was connected to in order to a simulate a power loss and see if the UPS can successfully transfer to battery but the PC just shut off.

The UPS's circuit breaker did not trip.

What's surprising is that I've had this same setup go into battery operation during this stress test at least twice before (that I triggered manually) and since the shut down event, I've repeated the same conditions twice over (same test) and it successfully transferred to battery every time. Including during idle & gaming scenarios as well.

I've had it go on battery during actual power loss events, and it never had a problem then either.

The UPS is rated for 1500va/980W and my system's power draw was around 650W with a peak of around 700 during the OCCT test.

The only variable that was unique during the incident where the PC shut down was that the battery charge level on the UPS was significantly lower than any previous (or since) instances of switching to battery. I'm not sure exactly how much it was but it had only 3 battery LEDs out of 5 lit up, as it had just come off of operating on battery for about 4-5 minutes during a similar high load test.

So I'm asking, was it the lower charge level that somehow led to a longer transfer time than usual? My PSU is ATX 3.0 compliant and is a good quality unit with 80+ Platinum efficiency.

[Teken]

Based on the very limited information you provided it sounds like the unit dropped the load as the battery capacity was not high enough.

The battery cartridge is rated for 2 - 4 years based on usage, temperature, and environmental conditions. If the power quality is poor in your area this will cause the unit to go into battery only mode more frequently and thus shorten its service life.

You can reduce this by changing the sensitivity and upper / lower transfer points.

If the temperature is very high this too will result in reduced service life. ☝️ For every one degree over the recommended operating range (0-40’C) this will reduce the battery service life by several percentage points.

READ: Percentage points is equivalent to reduction in months. Transfer time in most of the APC enterprise units is less than 2 ms. A low battery voltage condition will result in erratic performance and behaviour that can impact the transfer time.

[Parthu1708]

The battery (and UPS itself) are only about a month old.

For now it does appear that the battery's voltage (not the output voltage of the UPS) was reduced because of having a relatively low charge level at the time of switchover.