Question about my UPS

[bardos]

I bought a second hand UPS on ebay a while back, the seller saying there was a new battery installed... I've been noticing through testing (and blackouts) that it will last me only about one minute before shutting down.

It's an Eaton Ellipse eco 800 which uses by default one 12v 9AH battery. So I opened the case today to see what was happening... Basically I have a couple of 12v 7AH batteries sitting around and was thinking the guy had probably lied about there being a new battery in the UPS. I was thinking to replace the "bad" battery with a good one, but of lesser AH.

To my surprise, the battery inside *was* a 12v 7AH battery. It gave a 13v readout on my multimeter. Seemed good.

Anyway, I was wondering if this is the reason that the battery will only last one minute and if I throw a 9AH battery in there to fix it, the problem will end. Or what?

Any help with this conundrum appreciated. Thanks

 

[Mpegger]

The time a UPS last will also be dependent on what you have connected to the battery backup outputs, not just it's available output. What exactly do you have plugged into it?

 

[Xaotic]

There is a little data online, but I haven't found loading curves. Their PDF lists 11 minutes of life at 50% load and 6 minutes at 70% load. This is based on their specification of fully loaded power capacity of 500W.

One minute sounds short, but if you have monitors and other peripherals plugged into it, it's quite possible. If many are added, you could easily be overloading the system.

 

[bardos]

I have my PC and monitor an HP 24 inch thingie. I think my question is: what happens when you use a "lesser" battery than what is recommended?

I've got a USB cable from the UPS to the computer and it went from 100% charged to 94% when I pulled the plug and it was on battery life support. At 93% the comp died. I had at least expected to watch the percentage go down to hit zero or somewhere near.

 

[ATMINSIDE]

What wattage does everything draw in total?
That's the only way we can know how long it should last is if you tell us that.

 

[Xaotic]

As ATMINSIDE said, knowing the power draw is the only true way to tell.

I have my PC and monitor an HP 24 inch thingie. I think my question is: what happens when you use a "lesser" battery than what is recommended?

I've got a USB cable from the UPS to the computer and it went from 100% charged to 94% when I pulled the plug and it was on battery life support. At 93% the comp died. I had at least expected to watch the percentage go down to hit zero or somewhere near.

From this behavior, I'd venture a guess that you are actually exceeding the UPS's rated or perhaps actual capacity. This is generally what happens when a UPS is overloaded. It will attempt to respond to the load and then catastrophically fail, regardless of battery capacity. The battery could also be having issues, but I'm more suspicious of the load capacity of the UPS.

Does the behavior change if you unplug everything else other than the system itself from the UPS?

Downgrading the battery would not be a good idea.

 

[bardos]

As ATMINSIDE said, knowing the power draw is the only true way to tell.



From this behavior, I'd venture a guess that you are actually exceeding the UPS's rated or perhaps actual capacity. This is generally what happens when a UPS is overloaded. It will attempt to respond to the load and then catastrophically fail, regardless of battery capacity. The battery could also be having issues, but I'm more suspicious of the load capacity of the UPS.

Does the behavior change if you unplug everything else other than the system itself from the UPS?

Downgrading the battery would not be a good idea.

I'll check out the exact wattage use today....

What I am trying to say is that on opening the case, expecting to find an old decrepit 12v 9ah battery, I found the battery has already been downgraded... using a 12v 7ah battery when the specs call for a 12v 9ah battery. My basic question is: is this affecting the the amount of time without the mains on?

 

[Xaotic]

Sorry, I misread the initial post.

Runtime will be shorter and on anything without an extended run pack, that is a bad thing. Operationally, it probably will not make much difference, unless the manufacturer uses a really fast recharge cycle. This could lead to a cooked battery and associated issues. Eaton usually has decent power engineers, but it's hard to tell if they subbed the design and construction of units.

Since it already has one of this size in place, try runtime testing with a lower load first using one of your batteries and a smaller (non-computer) load. You can still monitor with the USB, even if the PC is not running on the system.