Replacing the Battery in my APC BX700-GR UPS

How to replace the battery pack on an APC Back-UPS BX700-GR.

Andrej Friesen

Sep 6, 2023 — 4 min read

The other day my UPS was beeping with a constant tone in the morning. So I went down to the NAS, powered it off, and disconnected it from the UPS. Then I turned off the UPS.

Powered the NAS back on without the UPS and had a look at the logs:

journalctl -u apcupsd
Aug 28 04:58:58 nas apcupsd[3594]: UPS Self Test switch to battery.
Aug 28 04:58:59 nas apcupsd[3594]: UPS Self Test completed: Warning
Aug 28 04:58:59 nas apcupsd[3594]: UPS battery must be replaced.

Star Trek GIF - Star Trek Hesdeadjim GIFs — I actually never watched that show!

Looks like my UPS battery is dead.

The model number for my battery is the GP 1272 F2 and costs around 25 Euros including shipping. A new UPS is way above 100 Euros. A new battery it is.

Replacing the battery

First, disconnect everything and also disconnect the yellow fuse on the back!

The front cover is held by 2 screws. After that, you can pop up the cover and see the battery.

UPS without cover and exposed battery connectors

I would recommend some pliers to get these connectors off. I cut my thumb during my first try with bare hands. Replace the battery and reverse the process and you are done with the physical part.

Tasks after replacing the battery

If you run the apctest while the apcupsd is still running you will get this error:

sudo apctest

2023-09-05 07:20:37 apctest 3.14.14 (31 May 2016) debian
Checking configuration ...
sharenet.type = Network & ShareUPS Disabled
cable.type = USB Cable
mode.type = USB UPS Driver
apctest FATAL ERROR in apctest.c at line 311
Unable to create UPS lock file.
  If apcupsd or apctest is already running,
  please stop it and run this program again.
apctest error termination completed

Lets stop the daemon then with sudo systemctl stop apcupsd.

Now we can run the sudo apctest command which gives us the following options:

1)  Test kill UPS power
2)  Perform self-test
3)  Read last self-test result
4)  View/Change battery date
5)  View manufacturing date
6)  View/Change alarm behavior
7)  View/Change sensitivity
8)  View/Change low transfer voltage
9)  View/Change high transfer voltage
10) Perform battery calibration
11) Test alarm
12) View/Change self-test interval
 Q) Quit

With 4 I changed the battery date.

Then I ran a battery calibration with 10. This will deplete the battery until 25% as stated from the output:

Battery level is 100% -- OK
Load level is 12% -- OK
Clearing previous self test result...CLEARED

The battery calibration should automatically end
when the battery level drops below about 25%.
This process can take minutes or hours, depending on
the size of your UPS and the load attached.

Initiating battery calibration...INITIATED

Waiting for calibration to complete...
To abort the calibration, press ENTER.

Battery level: 100%.
Battery level: 97%.....
Battery level: 96%.....
Battery level: 95%.
Battery level: 94%..
Battery level: 93%..
Battery level: 92%.

I should have adjusted the alarm behavior before that since this was beeping all the time 😅

You can also disable the alarm with the option 6. I do that because my phone will let me know if a service is down.

Select function number: 6

Current alarm setting: ENABLED
Press...
 E to Enable alarms
 D to Disable alarms
 Q to Quit with no changes
Your choice: Select function: D

My /etc/apcupsd/apcupsd.conf for reference:

Do you have a UPS for your NAS? If not I would highly recommend one. You do not want your disk to just lose power. I use mine just for a save power down. I do not need to run my server without mains power. Then you do not need to spend a lot of money as well.