My APC Back-UPS Pro 1200 seems to be running only on the battery, with no way to charge it

[nsin]

The UPS is used in a work environment with a router and firewall connected to it, one day when I came in it was constantly beeping every few seconds, I restarted it and it stopped, but it seemed to be running on the battery instead of on line, the next day someone else did the same thing, but it only stayed on for a few minutes.

Now I'm trying to get it working, but the display wont light up, I've tried disconnecting everything from it, plugging it in in different places, running it without battery, to no avail. It seems to be running in some capacity as i can hear it working, but without charging the battery or providing power to the connected devices. Sometimes it lets out a half a second beep when I press the power button.

The battery was swapped in last December and there were no signs of any issues until now.

I'l gladly provide any additional information you might need and am glad for anyone interested in helping.

[Teken]

If we assume the best case scenario the reason the UPS would be running on battery only mode is due to a power failure, dirty power.

At this point you’ll need to confirm what the battery voltage is by measuring it with a meter. More than likely it will be flat / dead so you’ll need to recharge it with a 12 / 24 DC charger. If you don’t have a 24 DC charger remove the middle bridge connector so you can charge each 12 volt  cell separately. ☝️

Assuming the battery recovers and is useable stick it back in to the UPS. Power up the unit and wait for the Self Test to complete its going to pass / fail.

If it passes (good) now read what the LCD says is the current state of the battery charger, input / output voltage.

It should say charging and input / output appropriately 120 VAC in North America or 230 240 VAC in EU etc.

If the battery is toast the unit won’t power on. So have a good battery on order or ready to insert. If the new battery shows the same behaviour of running on battery only mode.

You’ll need to install APC Power Chute Personal Edition (PCPE) software to a computer and connect the two together. Assuming the unit turns on it will capture the active faults / errors seen on the system.

Report back what you see and observe.

NOTE: If this hardware is under warranty it makes sense to contact APC Technical Support for assistance and (IF) required they can provide a replacement battery or RMA the unit if they deem the hardware is defective / damaged.