I have a fairly ancient SU2200INET. I last replaced the batteries about 4 years ago, but my current monitoring logs only go back to December. Even from those, something strange has been happening with the battery capacity in terms of Wh. The UPS doesn't report this directly - I am inferring it from the following two values reported by the UPS:
1) LOADPCT (% load, assumed to be % of 1600W maximum rated output)
2) TIMELEFT (seconds left with current load on current battery charge)
From these two, I work out the battery capacity.
I can see that 8 months ago, it was about 280Wh. In that time there have been two calibrations and maybe 3-4 power outages, and the battery capacity now is showing 42Wh. The self tests pass, and the UPS says the batteries are OK.
I also recently acquired a much newer SUA3000I and with the same batteries (different connector but identical batteries), and that is showing close to 400Wh battery capacity after calibrating.
So I figured the battery capacity is expected to be about 400Wh, and with my old batteries being down to 42Wh, means that they are down to barely 10% of their capacity and it's time to replace them. Yet the UPS was saying they are fine. Is that sane/normal, especially since the UPS doesn't show the battery capacity directly, and I have to infer it from the two values mentioned?
I just got replacement batteries, fitted them, recalibrated - and they are also whosing 42Wh capacity. How is that possible? The load on the UPS hasn't changed in the past year, yet the battery endurance is showing as far shorter than before and new batteries haven't resolved the problem. How is that possible? Why have new batteries not restored the time on battery I had before on a new battery pack?
Found a solution:
Why is this not handled automatically by the firmware in the network card when the battery date is reset?
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