UPS Question

[DigitalDivide]

I have a Back-UPS ES 550G which I replaced the battery about 6 months ago.  Tonight the power went out in my condo and within 2min I got a message from my tower that it was shutting down.  I got two emails which are below.  What surprised me is how fast the tower shutdown.  The power outage only lasted 5 min. When I look at the UPS Settings on the Tower it shows the specs below.  I'm not sure what item I should specifically be looking at.  I only have the UPS and my router and modem plugged in and nothing else.  I'm really surprised it didn't last longer.

 

1st

Event: unRAID Server Alert
Subject: UPS Alert
Description: Power failure on UPS Tower. Running on batteries.

 

2nd

Subject: UPS Alert
Description: Battery time limit exceeded on UPS Tower. Doing shutdown.

 

 

APC	001,034,0839	DATE	2018-02-20 22:01:08 -0500
HOSTNAME	Tower	VERSION	3.14.14 (31 May 2016) slackware
UPSNAME	Tower	CABLE	USB Cable
DRIVER	USB UPS Driver	UPSMODE	Stand Alone
STARTTIME	2018-02-20 21:52:02 -0500	MODEL	Back-UPS ES 550G
STATUS	Online	LINEV	121.0 Volts
LOADPCT	36.0 Percent	BCHARGE	82.0 Percent
TIMELEFT	13.2 Minutes	MBATTCHG	10 Percent
MINTIMEL	10 Minutes	MAXTIME	30 Seconds
SENSE	Medium	LOTRANS	92.0 Volts
HITRANS	139.0 Volts	ALARMDEL	30 Seconds
BATTV	13.6 Volts	LASTXFER	Unacceptable line voltage changes
NUMXFERS	0	TONBATT	0 Seconds
CUMONBATT	0 Seconds	XOFFBATT	N/A
STATFLAG	0x05000008	SERIALNO	4B1448P27100
BATTDATE	2014-11-27	NOMINV	120 Volts
NOMBATTV	12.0 Volts	FIRMWARE	904.W1 .D USB FW:W1

[JonathanM]

Sounds about right for a UPS that small. Do you happen to remember what Ah spec the battery was?

 

Also, remember that in order to shut down, unraid has to spin up all the drives and do shutdown housekeeping, so the current draw during shutdown is pretty close to max, much more than idle.

[Frank1940]

IF you look at the output from the 'UPS details' chart in the original post, you will see that this:

     

MAXTIME

30 Seconds

 

This is the time that the UPS will supply power on battery before it signals for the shutdown procedure to begin.

 

BTW, this is actually a good value to have this short a time before shutdown start.  The problem with using longer times are many.  The two must important ones are these.  First, the time on battery at present load is a SWAG (Stupid Wild A$$ Guess).  As the battery ages, this time is even less accurate and the battery can fail to supply the required current and the UPS will just shutdown at that point.  Second point is the one which the OP referenced.  The power comes back on after being out for a few minutes.  Someone assumes that it is back on for good and restarts the server.  Ten minutes (or even two hours) later, it goes out again. The battery has not recharged enough to conduct a clean shutdown.  (It will take about eight hours to fully recharge the battery.)

[DigitalDivide]

The battery replacement was the official one, http://www.apc.com/shop/ca/en/products/APC-Replacement-Battery-Cartridge-110/P-APCRBC110

 

I have no problem with the quick shutdown really. I think I was just more surprised it was so quick.  I just thought it hold for a few hours but I guess I would have needed a bigger one.

[Frank1940]

A UPS for a few hours is called a generator....   A lead acid battery with that type of capacity would be the size of a file cabinet drawer! The objectives of a battery powered UPS are (1) to shut the system down cleanly and (2) to prevent power transients from causing damage to both equipment and data.  

[JonathanM]

8 hours ago, DigitalDivide said:

I just thought it hold for a few hours but I guess I would have needed a bigger one.

For a few hours of clean power, plan to spend well over $1,000 USD, and have a cabinet just for the batteries, and another for the UPS electronics.

 

 

[DigitalDivide]

lol...ok I get the idea