APC ES-350 Turns off by itself in the night time.

[Anonymous user]

Hi, I just recently moved to a new house. I've had the same problem the past 2 nights. I'll wake up and the APC ES-350 UPS unit (5 years old) is completely off. It did have a computer, monitor, computer speakers, Internet modem, printer and router attached to it. The power seems a little sketchy here, like when I run the microwave or turn on my audio receiver (both attached to different power outlet), the backup will kick on for a quick second and go back to "normal". I'm not sure if the UPS makes any beeps, since I'm in bed. The wiring fault light is always on, not sure if that could be an issue?

It is strange since it runs fine during the day when I'm up, then turns off when their is no huge amount of power being used at night. I did just move the UPS to a different wall outlet and plugged the printer into a different outlet as well. Any ideas will be greatly appreciated. Possibly bad battery or fault in the unit or just bad power at my new house?
Thank you.

[Anonymous user]

Hi, when I moved the UPS to another outlet (all outlets are 3 pronged) the battery came on (beeped) when I unplugged it. So, I believe that is alright. When turned back on I get a Green light, a slight humming sound for about 5 seconds and that goes away after that. The switching during the day hasn't happened in a week or so. I went outside and I see that we have a ground wire coming out of the electrical meter to a spike in the ground. But like I said I have 2 other surge protectors, in different outlets, and both say that they are not grounded; which I find very odd (maybe why the wiring fault indicator is on?). I lightened the load and moved it to another outlet, so I will see how it goes for the day/night. Will let you know what happens tomorrow. Thanks for the help.

[BillP]

do you see any LEDs when you turn it back on? if so, what color/combination?

i dont think the site wiring fault is related but that is explained here -> http://nam-en.apc.com/app/answers/detail/a_id/183

are you 100% sure that the unit works correctly as far as switching to battery? you mentioned that you see it switch during the day. i would try a pull plug test with a non critical load to see if you plug something into the battery back up outlet(s) and see if the UPS supports the load after removing the plug from the wall outlet. you could also run it for at least a few minutes. i am thinking either the UPS switches to battery during the evening when it flickers and the battery cant support the load so it turns off or it just exhauts its runtime during the evening because of an outage, as expected.

[Anonymous user · Accepted solution]

There is a newer post about the same model with the same condition, it was started by user bunkerfire, I am starting to think that there might be a big problem with this device.

Ivan, I was stating in the other thread that I have a few of these devices attached to workstations to provide power during an outage for 10 secs until the building transfers to generator. Well I have about 10 of these units, and they will shutdown a computer with out notice, so I have had to stop using them until I can figure out what to do with them,

Message was edited by: rclipper