UPS Issue

[a12vman]

Here we go again. I still can't get a handle on why my server is shutting down within seconds of a power loss.

 

UPS Power Level was at 100% before the power loss - the batteries are less than 6 months old.

 

I asked this question before - how do the redundant power supplies work in my server, are both always drawing current? 

 

I have both of them plugged into my UPS.  This is a Dell server.

 

Unconfirmed but I am reading that Dell splits the load across both PSU's until one fails.  

 

Could that be causing my issue?  Running on battery for < 90 Seconds going to shutdown takes my battery charge down to 70%?

 

 

 

Edited January 31, 2021 by a12vman

[Tom3]

Not sure if the table above is right after the discharge event, or after the batteries have been charging for awhile.

 

On the graphic it shows BATTV as 42.3 volts.   For a 48V lead-acid battery at room temperature

that's about 1% charged (99% discharged).  The table also shows BCHARGE at 71 percent.

Those two numbers disagree with each other.

 

While float charging, the battery should sit at 54.4 volts for 100% capacity.

 

Some Q&A at Dell Community says that R710 server supplies load-share, except when lightly loaded.

https://www.dell.com/community/PowerEdge-Hardware-General/PowerEdge-dual-power-supply-and-power-load-balancing/td-p/3448711

 

-- Tom

 

 

 

 

 

[a12vman]

My UPS uses 3 x 12v 7ah batteries. I bought 3 of them back in July 2020.

https://www.amazon.com/gp/product/B003S1RQ2S/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

Here are the stats when fully charged ups settings show 36.9 minutes of Runtime available and 24% Load.

 

Edited January 31, 2021 by a12vman

[JonathanM]

Have you tested the UPS runtime on a switched circuit with an equivalent dummy load attached?

[Tom3]

OK,  36V is an unusual UPS battery bank voltage.   My numbers assumed a 48v bank.

 

Does your server load increase when the UPS switches on?    Sometimes the

server starts a shutdown process which increases the load.  The 36.9 minutes

I think assumes the UPS goes to 0% charge.   The table above appears to be to shutoff

when the battery gets down to 25%, and MAXTIME of 1800 seconds (30 minutes).

The table shows  OUTPUTV of 0.0 volts.  Not sure what that refers to, my UPS driver

does not provide that parameter.

 

 

[a12vman]

What does your OUTPUTV parameter show?

 

Here are my 3 parameters.

My understanding is that shutdown will initiate if any of the 3 conditions are met:

Battery Level Falls Below 25%  OR

Time on Battery Exceeds 1800 Seconds OR

Calculated(By UPS) Battery Runtime < 10 Minutes

Edited January 31, 2021 by a12vman

[a12vman]

Yes I load tested these batteries.

 

With nothing else plugged but a Halogen Work Light(confirmed power draw with Kill-A-Watt @ 400w).

 

With the Halogen on and plugged into the UPS I flipped the Breaker Off.

 

It ran on Battery Power for 4:45 seconds before it dropped from 3 Bars down to 2 Bars.  Left it run for another 2 minutes with plenty of power to spare and then I turned it off.

[JonathanM]

1 hour ago, a12vman said:

Yes I load tested these batteries.

 

With nothing else plugged but a Halogen Work Light(confirmed power draw with Kill-A-Watt @ 400w).

 

With the Halogen on and plugged into the UPS I flipped the Breaker Off.

 

It ran on Battery Power for 4:45 seconds before it dropped from 3 Bars down to 2 Bars.  Left it run for another 2 minutes with plenty of power to spare and then I turned it off.

Try repeating the test, with the server running but not fed from the UPS with the USB connected and see how the server reacts.

[a12vman]

I will try that next. 

 

I just set the parameters low and re-ran the test.:

Runtime left to shutdown= 4 minutes

percent Battery remaining to shutdown=20

time on battery before shutdown in seconds=0 (Unraid help says 0 will disable this timer).

 

Server went into shutdown mode ~ 3 minutes after power went out.

 

interesting though my UPS gives a beep-beep-beep every 15 seconds when on battery power.

After the ~ 3 minutes on battery the ups emits a continuous tone and that's when the shutdown starts....

 

The last value i see in UPS Settings before server goes offline shows 89% battery Remaining.

 

 

 

Edited February 1, 2021 by a12vman

[JonathanM]

Did you reset the battery date in the UPS firmware?

[a12vman]

Yes I did.. I followed the instructions from Tripp Lite. Here is the Tripp Lite app reporting info on my UPS.

 

I am starting to wonder is there is an issue with apc ups daemon and how it interacts with my Tripp Lite.  

 

The continuous audible tone that comes from the UPS warning of a very low battery, does the ups initiate that or did it come from the APC Ups Daemon on UNRaid?

 

Edited February 1, 2021 by a12vman

[JonathanM]

14 minutes ago, a12vman said:

The continuous audible tone that comes from the UPS warning of a very low battery, does the ups initiate that or did it come from the APC Ups Daemon?

Gut feeling says UPS, but that's easy to test with your dummy load.

[a12vman]

Ok here is more info.  I have a halogen work light that draws 425 watts.   

 

I confirmed that my unraid server(with both power supplies plugged in) draws ~ 190 watts running under normal load.

 

I powered down my unraid server, disocnnected power and usb from my UPS.

 

With my halogen light plugged into my UPS running on battery power I got about 7 minutes of battery time before the solid audible alarm went off.

 

The Solid audible alarm went off when the UPS power indicator dropped from 2/3 bars to 1/3 bars.

 

 

[Frank1940]

I am going to ask a very dumb question.  If your power fails and is out for 30seconds, what percentage of the time will it be restored within 30 minutes (1800 seconds as based on your settings)?

 

The reason for this question is rather simple.  In most places in the developed world, if the power is out for thirty seconds, it will usually take hours to repair the problem.  You might as well acknowledge that fact and shut the server down (after thirty seconds or so) and preserve the battery charge.

 

Why do we want to preserve the battery charge?  Because when the power is restored, most of the time, one will want to restart the server as soon as possible.  BUT it will take upwards of 24 hours to fully recharge the battery!   So if there is a second power outage before that time is up (and the odds are fairly high this will occur), there may not be sufficient battery capacity to successfully shut the server down this time.  So you will now have an unclean shutdown which is the whole point of having an UPS. 

Edited February 1, 2021 by Frank1940

[a12vman]

I set that value very high for testing purposes, trying to isolate if one of the 3 parameters in the A or B or C condition was causing the problem.

 

I would normally set that value at 300.

 

This is a very frustrating issue to me.  On one hand I am happy that the server always does a clean powerdown.

 

On the other hand I don't have a clear understand as to why it is shutting down before any of the 3 requirements have been met.

 

I get my electricity from my local village that has their own power power station.  The majority of the power outages that we get are blips((last anywhere from 1-3 minutes).

 

I don't expect the UPS to keep my server running for 30 minutes but I don't think 5 minutes of runtime is too much to ask for a server that under normal conditions is drawing < 200 watts.

Edited February 1, 2021 by a12vman