Smart-UPS 750 - Rack mounted - Battery Error Loop

[Noor989]

Hi,

Well wishes!!

The UPS gives of an error message that the battery is disconnected, but then automatically the error disappears and it works again > Then again error message comes up > The whole circle on repeat

Leave it long enough and the battery shows connected and does not go into error loop. But after some time it starts again. Video Attached.

If not in loop; It says the battery is at 100% and "Replace Battery by: Jan-2026". I tried disconnecting and connecting the battery all while it was running - hot swap but it didn't help. 

UPS Part No: SMT750RM2U

Any help would be appreciated!!

[Teken]

Show me the battery production sticker on the physical cartridge. 

Questions Ask . . . 👍

[Noor989]

Is the attached what you asked for?

[Noor989]

 Is this Production Sticker?

[Teken · Accepted solution]

Based on the image you provided the battery cartridge is four years old as it was produced in 2021 (22 week).

The average service life of a battery cartridge is 2-5 years based on usage, temperature, and environmental conditions.

You may order another RBC123 from APC / authorized retailer or simply rebuild the pack with high quality cells with the same amp hour rating.

If you go down this route you’ll need to reuse the top plate etc.

Questions Ask . . . 👍

[Noor989]

Thanks Teken, Didn't knew that aged battery can make APC react like that. I thought it was a connection issue within APC causing. I'll try a new battery and update if possible....

[Teken]

You can test that theory out right now. Simply disconnect the battery cable from the unit and wait for system to declare a battery fault.

Wait ten seconds more than reconnect the battery cable.

The system will prompt you to confirm if the battery cartridge has been replaced. Toggle from No to Yes and input the current month and year and press enter.

Follow up by manually initiating a Self Test and let pass and allow the battery to recover to 100% SOC.

Keep in mind doing the above is simply fooling the system into thinking everything is fine! ☝️

This (May) help you limp by until a new battery cartridge arrives. But, keep in mind it’s more likely the entire system will randomly begin to crash as you see now.

Doing the above procedure is simply a band aid test. Give it a try as you have nothing to lose at this point. As you still need to replace the battery cartridge anyways.

Questions Ask . . . 👍

[Noor989]

Initially I started a self test - the APC went down and everything plugged in went down with it. I thought the self test could be done while its live but was wrong. I then didn't wait for it to come back up and powered on the APC manually. I'd rather change to the new battery than pulling this a second time in the live environment......

[Teken]

If the system went down during a Self Test it’s most definitely a battery issue.

[Noor989]

Thanks have ordered the replacement and will update once received and tested!