[Nut-upsuser] System with MGE UPS shuts down too early
nicolae788 at gmail.com
Mon Jan 27 08:38:05 GMT 2020
I sometimes encountered batteries that were ok, but at times one of the
cells would develop a random short/open, therefore reducing the real
capacity even if voltage reading was ok. In the absence of a battery load
tester i would suggest running multiple tests with a load (car headlight
bulb or similar) on the battery outside the ups. This is to eliminate the
suspicion of a software or UPS unit fault.
On Mon, 27 Jan 2020, 02:53 Manuel Wolfshant, <wolfy at nobugconsulting.ro>
> On 1/25/20 10:53 AM, Georgi D. Sotirov wrote:
> OK, so yesterday evening I done a real test cutting of the power to the
> UPS. And it went good... the UPS supported my server for 28:50 minutes
> (i.e. the expected runtime with this load), before forcing shutdown. The
> batteries could still hold as charge was 30 % with about 15 minutes run
> time. And the UPS did hold for another full 10 minutes before powering off.
> These are the relevant lines from /var/log/ups:
> 20200124 201318 32 0.0 12 [OB] NA 0.0
> 20200124 201323 30 0.0 13 [ALARM OB LB] NA 0.0
> 20200124 201328 30 0.0 13 [FSD ALARM OB LB] NA 0.0
> 20200124 201333 30 0.0 13 [FSD ALARM OB LB] NA 0.0
> 20200124 201338 30 0.0 13 [FSD ALARM OB LB] NA 0.0
> 20200124 201340 30 0.0 13 [FSD ALARM OB LB] NA 0.0
> that looks perfectly fine
> The server was shutdown properly, but for some reason it did not power
> off. I saw an error from umount about busy file system, but I'm sure this
> doesn't always happen.
> the error is related to your linux system, not to nut
> With everything powered off, I extracted the original batteries to check
> them and measure the voltage. The batteries are Leoch DJW12-9.0 with one of
> them at 12.57 V and the other at 12.64 V (measured without load after the
> That's... surprisingly well, assuming your multimeter indicates correct
> values. I would have expected values well below 12V
> And this morning there was again a short power failure (not more than 30
> minutes, because the router connected to the battery power from the UPS did
> hold up). With batteries charged up to 91% the UPS supported the server for
> just 07:10 minutes and forced shutdown with 69% battery charge and over 20
> minutes of run time...
> 20200125 021123 70 0.0 16 [OB] NA 0.0
> 20200125 021128 69 0.0 16 [FSD ALARM OB LB] NA 0.0
> 20200125 021133 69 0.0 16 [FSD ALARM OB LB] NA 0.0
> 20200125 021138 69 0.0 16 [FSD ALARM OB LB] NA 0.0
> 20200125 021143 69 0.0 16 [FSD ALARM OB LB] NA 0.0
> 20200125 021148 69 0.0 16 [FSD ALARM OB LB] NA 0.0
> 20200125 021150 69 0.0 16 [FSD ALARM OB LB] NA 0.0
> So, it seems to me that my UPS forces shutdown pretty randomly. Why the
> UPS is not waiting for the preset low battery charge value of 15%? What is
> actually driving this FSD ALARM and LB signal when batteries for sure could
> hold up more?
> Can you please show us all the configuration files ? I can only suspect
> that there is something wrong there because (from a hardware point of view)
> the UPS behaves very very well, according to your tests and logs.
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