I've known this for ages. And, have taken steps to ensure I can't be "bitten" by it on all my UPSs.
But, apparently, forgot to "fix" one of them -- a SmartUPS C1500. No doubt because it doesn't support a NMC (which is how I manage the herd).
The symptoms are a rebooted computer -- but no "events" reported on the UPS (so, you figure it must have been a software crash). The TELL-TALE symptom is a computer that you find rebooted The Next Day... at virtually the same time (within seconds).
What's happened is the UPS has done its daily self-test and the battery -- which displays as "100%" -- was unable to support the inverter. So, power to the PC fails. The UPS comes out of the self-test (reboots) and doesn't know that anything "bad" has happened (cuz it has forgotten!). The PC reboots and all is well -- until the next day, 24.00 hours later.
The fix is to disable the self-test feature. Worst case, a battery that is in this condition (reporting 100% yet not able to support the inverter) will cause your system to crash WHEN THE POWER FAILS -- which is usually much less often than "every day"! You won't have to remember that the UPS "stages" a power failure every day as the reason why your machine is rebooted.
Eventually, I'll figure out why the battery health reported is so wrong. But, as REAL power failures are few and far between, I can put that off for a while...
But, apparently, forgot to "fix" one of them -- a SmartUPS C1500. No doubt because it doesn't support a NMC (which is how I manage the herd).
The symptoms are a rebooted computer -- but no "events" reported on the UPS (so, you figure it must have been a software crash). The TELL-TALE symptom is a computer that you find rebooted The Next Day... at virtually the same time (within seconds).
What's happened is the UPS has done its daily self-test and the battery -- which displays as "100%" -- was unable to support the inverter. So, power to the PC fails. The UPS comes out of the self-test (reboots) and doesn't know that anything "bad" has happened (cuz it has forgotten!). The PC reboots and all is well -- until the next day, 24.00 hours later.
The fix is to disable the self-test feature. Worst case, a battery that is in this condition (reporting 100% yet not able to support the inverter) will cause your system to crash WHEN THE POWER FAILS -- which is usually much less often than "every day"! You won't have to remember that the UPS "stages" a power failure every day as the reason why your machine is rebooted.
Eventually, I'll figure out why the battery health reported is so wrong. But, as REAL power failures are few and far between, I can put that off for a while...
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