power efficiency of UPSes?

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BLinux

BLinux

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Jul 7, 2016
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I have 2 APC SUA1500RM2U units that have served me well for over a decade. They've saved me more than a couple of times over the years. However, I recently saw a youtube video of a guy who converted one of these old UPSes to be a sinewave inverter. In that video, it seems these UPSes consume about 40-50W just sitting idle! I did't measure mine yet, but has anyone looked into this to see how much power is wasted just running the UPS?

And if old UPSes waste a lot of watts, how much better are the newer models? And are there any specific UPSes that are more energy efficient than others?
 
marcoi

marcoi

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Apr 6, 2013
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the only home ups i actually saw use power was my double online conversion unit. Regular sinewave ones never registered on the kill-awatt. the double online runs power into battery to charge, and then the servers run off the battery ( was only way to deal with house brownouts and sensative servers). I think last i measured it added like 50-100 watts when running in that mode.
 
R

Rand__

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Mar 6, 2014
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A SMX1500RMI2U. Would have preferred larger but since they are quite new that was difficult to do on the cheap.

I found that basically all the old ones don't get firmware updates any more so I am only focussing on SMT/SMX models nowadays.
 
cheezehead

cheezehead

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Sep 23, 2012
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UPS units like power supplies have certain level of efficiency when being used. With APC units for what limited information i've found they generally carry a decent efficiency when over 40% loaded, peak efficiency on the particular unit is 95% given full load.

Management cards take 3-5w if memory serves.

(for comparison's I'm looking at the 1440-1500va...each vendor is a bit different)
Efficiency metrics aren't detailed in terms of watts directly but at overall efficiency of a unit. You can find how much is wasted in terms of heat though. At full load this particular unit generates 171BTU/hr which would equate to ~50watts given off as heat under full load. If you upgraded to a more modern SMX1500RM2U this would drop to 133BTU/hr ~39watts. If you moved to an even more efficient Eaton unit (5P1500RC) you would be down to 113BTU/hr at full load ~33watts.

So are there savings in moving to something newer, yes....the question is it worth the expense to save a couple of watts.

For home lab scenario's i've stayed with used APC gear purely because they can be picked up locally for pennies but for new deployments I'd look at Eaton as they are cheaper than APC, better warranties, and have a better charging method (more years between battery replacements).
 
cheezehead

cheezehead

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BLinux said:
@cheezehead so you really like the Eaton UPSes? are they superior in every way to APC? or is there some trade off?
Click to expand...
Eaton's charging circuits are better...ie batteries last longer and there's less heat produced. The warranty in the US for APC is 3yr (2yr battery) while registered Eaton units is 5yr (includes the battery). They have smaller units with multiple output groups which can provide some additional flexibility (ie handling in-rush issues without a separate switched PDU).

In a larger environment, pick one or two up and test them out in a closet somewhere. Remember the total cost UPS unit + management card + management software + service contracts (if required).

The biggest trade-off for many is history and purchasing sources. APC has been used by orgs for decades of all sizes, Eaton doesn't have that history which is a big deal for some. APC can be purchased pretty much anywhere while Eaton isn't in local retail generally (suppliers yes, but not retail). Integration wise APC is always the first UPS line for monitoring, Eaton is there usually but not day one.

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