UPS Questions

paulyron · August 31, 2022

Bought a CyberPower 1500 VA UPS years ago. Reason being where I'm located, there were power outages occasionally and because of that, I wanted a battery backup for my xps 15 9550 laptop if power goes out. I normally connect my laptop, 2 external monitors, modem/router and anything else to a surge protector. I rarely have the UPS on or anything connected to it.

When I got the UPS, I remember charging it for a long time. It always showed like 410 minutes runtime or so if you don't connect nothing to it and its on. I rarely used it because I didn't have much power outages after that. Now the thing is a while back I remember even though it's always plugged to wall outlet, I didn't power it on. I remember once it wasn't even plugged to the outlet for a long time. I then came back and then charged it to the wall outlet but I rarely have it turned on or even power it on. So I make sure I charge it for a while and then power it off. Then when needed, I would connect it to my laptop if power outage and I need to continue using laptop.

Now for a long time, I have not powered it on. I left it connected to wall outlet but it is not powered or nor any of my devices plug to it. I had heard a while back if you leave your UPS on all the time, electricity can get very high? So I figure I only use it when necessary. I wanted to test how long my laptop can use the UPS as a test. I remembered doing this a while back and think you could easily get over an hour with it. But when I connected only my laptop charger to the UPS, first thing I notice was the runtime went from like 410 minutes to 220 minutes. That make sense because previously there is no load at all so runtime should be very high. I then unplugged the laptop charger from the UPS.... only the side connecting to the charger and not the connecting side. I then powered the UPS off. I then unplugged the UPS from the wall outlet. I then powered on the UPS and it immediately powers off? So does this mean the UPS is bad then or the battery is worn? It does show 100% battery though whether its plugged in and powered on but nothing connected.... and also when I connect my laptop charger to it. Does that mean because I didn't charge my UPS for a long time, I need to charge it for a long time before it work? Or is the battery no good? Because say I have it plugged in with the laptop now and it is charging. Well if there is a power outage now, well the UPS is going to turn off.

Electronics Wizardy · August 31, 2022

How old is it? About 5 years is the expected lifetime for the battery in a UPS, so Id guess your battery has gone bad here. I have had UPSs that will die when removed from wall power, and a new battery fixed the issue.

A UPS isn't really made for this usecase, and I think a battery bank would be better suited to these uses if you were to replace this.

An0maly_76 · August 31, 2022

A UPS isn't really something you can pick and choose when you need it. They're best left running all the time. I don't know what you're referring to about electricity being very high if left connected full-time, but the reality is that if it's not connected when you lose power, that sort of defeats the purpose of having it. That said, EWizardy is right -- battery is likely at or nearing the end of its service life. It shouldn't be that hard to replace.