SUA 1500I: all(!) LEDs flashing periodically

[w.klein_apc]

Hello!

I bought a second hand UPS, of which I was told it was working perfectly before it was shipped to my address. I tend to believe the seller, but nonetheless: the device doesn't work. As soon as I plug in the battery and connect the AC cable, all LEDs on the front begin to flash periodically and a small beep is emitted every time, as seen in the small video.

First I thought the battery was just totally empty, so I let it beep and blink for some hours. The blinking frequency has indeed changed: after 20 hours connected to AC it's just one beep/blink every 4 seconds. When it started, it was 1 beep per second.

But still the device does not react to any button: I can neither turn it on nor off. There is also no power on any outlet. And the PC can't find any USB device either. The manual stated that batteries can be changed while the UPS is running, without the need to power down the connected computer. To my understanding this would mean that there should be power to the outlets, even when the battery is worn out.

Does anyone have an idea what could be wrong with this UPS? Many thanks in advance for any help.

Supplemental: when I plug of AC and pull out the batteries, there's still some voltage on the battery connectors: it started at 300mV and that voltage is rising. Right now it's 510mV, and still rising. Where does this voltage come from?

[BillP]

i face the same problem ,measure battery voltage found it 21VDC

change it with new one UPS work normal ,will stay it on charging 8 hours and make runtime calibration

[BillP · Accepted solution]

Sorry for the delay and thank you for the video.

This is likely the UPS trying to do its self test, failing, and re-attempting. It is worth checking the battery voltage because if it is very low, it could cause this problem. If you have spare set of batteries, it's worth a try. Otherwise, it is likely another internal fault such as bad capacitors.