BX1200-CN will not switch to AC power

[HarryP]

I have a BX1200-CN and had a power outage late at night a few days ago so I didn't notice any issues until about 12 hours later. At the time my UPS was switching from the green light (on AC power) to the yellow light (on battery power). I disconnected all devices and hit the button turn it off and to let it charge overnight. A day later when I switched it on the green light flashed for a second but then it started repeatedly switching between AC power and battery power again. So, thinking the battery was defunct I ordered a new one. I installed it last night and plugged the UPS in to charge; the wall outlet definitely has power. Today I hit the button and it flashed the green light and then switched to a steady yellow. I hit the reset button on the back but I could see it was not triggered but hit it anyway but no change. Any idea why this is happening or what I need to do?

[Teken · Accepted solution]

A few things to ask and do which is to install Power Chute Software on to a Windows computer system and connect it to the UPS.

Once connected please report back what the system indicates as the input voltage / output voltage is. If there are any active faults or error codes please call them out. If there are power issues present the software should be able to capture that for you. 

In the interim you can try the brain dead procedure to see if it resolves the issue. This procedure essentially tries to reset and clear the unit of any random faults / errors in the system. 

Brain Dead: Remove all connected loads. Disconnect the AC Mains from the wall. Disconnect the internal battery. Press and hold the power button until you hear a click / beep.

You may hear nothing at all . . . ☝️

Reassemble the unit and connect it to AC Mains of the wall outlet. Press the power button and let the unit complete its (POST) Self Test.

Report back how the unit behaves with nothing attached. 

[HarryP]

Hmm, it didn't occur to me to check it out using the software.The input voltage fluctuates between 114 and 124 volts. Where does it report the output voltage? I don't have anything connected to the back at the moment since I have an alternative UPS that my computer is connected to. While I was connected to the UPS I tried reducing the sensitivity to medium from high and that seems to have done the trick since it is now operating normally with just the solid green (top most) light. I am going to use this UPS to support my audio/video system. If I remember correctly I had set the sensitivity to high at least 5 years ago so I don't know what has changed in my environment. Anyway, thanks for the prompt to use the software; I was at my wit's end thinking I had the wrong battery (RBC33 instead of RBC32), bent a pin, the circuitry was failing, etc. This model is a bit of a black box since it only has the ability to flash lights or beep at you.

[HarryP]

wow, the web site timed out while I was performing some of the items requested so I lost my post. Anyway, I connected the ups to the PC and checked the software and could see the device. The voltage was fluctuating between 114 and 124 volts. I changed the sensitivity to medium from high and the ups went into normal operating mode. If memory serves I had set it to high over 5 years ago so I don't know what has changed here. Where does PowerChute report the output voltage?? Since the ups is now running and passed a self test I am going to move it to support my audio/video equipment instead of this PC. I have another more modern ups currently supporting the PC that I had swapped in when all this happened. Thanks for your help; no idea why I didn't think about using the PowerChute software to take a look at the old ups. I've replaced batteries several times in the past and all I did was swap them and let it charge before turning it on.

[Teken]

Hi Harry,

Appreciate you taking the time to install Power Chute Software and reporting what you saw and the changes you made.

As you noted the software indicated the line voltage was outside of the defined values you set and thus the unit went into battery only mode to provide the cleanest power to your connected loads. 

Changing the sensitivity from high to medium increases the upper and lower transfer voltage to be wider. Thus the unit will allow a larger voltage variation before going into battery only mode.

NOTE: All three (Sensitivity) settings from normal, low, medium, high will never put your electronics at risk. 

Rock On . . . 🤟