UPS Scam?

[Michael Daly]

I went out looking for new batteries for my UPSes and discovered something interesting. The same battery works in several models - 250VA, 350VA, 400VA up to 500VA. Now the battery capacity is the number one determinant of the capability of a UPS so that means that the cheaper 250VA has (potentially) the same capability as the pricier 500VA unit. I can see that they might put a limit on what the circuit will deliver from the battery (making the battery look smaller) but somehow that ruffles my feathers.

Am I overlooking something that makes this an oversimplification?

 

[nobody_here]

theres likely a difference in the amount of current, or amperage the larger rated model can deliver also

 

[FlyinBrian]

It is likely that the higher rated ones use the same battery, just more of them.

 

[davidhammock200]

What company?

With APC some batteries are interchangeable, however the control circuits are very different.

 

[Michael Daly]

It is likely that the higher rated ones use the same battery, just more of them.

Nope - the ones I'm referring to all use just one - 12V 7.2AH gel cell.

 

[Michael Daly]

With APC some batteries are interchangeable, however the control circuits are very different.

It's APC.

What are the significant differences in the circuits?

 

[davidhammock200]

It's APC.

What are the significant differences in the circuits?

Go to the www.apc.com, there are pics, white papers, etc.

 

[tdg]

The 250 VA in the scenario would be capable of the same runtime as the 500 VA... but at a load of 250 VA max. The 500 VA (should) have a beefier transformer, and other guts which makes it capable of delivering more power, or the same power for a longer period of time.

I have a bunch of APC Smart-UPS 1400's, several workstation units, and a couple rackmount units. Same wattage capability, but different staminas, as the workstation units only hold 2 batteries, the racks hold 4. The racks do have a slightly beefier transformer, and seem to cool better as such.

 

[nobody_here]

The 250 VA in the scenario would be capable of the same runtime as the 500 VA... but at a load of 250 VA max. The 500 VA (should) have a beefier transformer, and other guts which makes it capable of delivering more power, or the same power for a longer period of time.

I have a bunch of APC Smart-UPS 1400's, several workstation units, and a couple rackmount units. Same wattage capability, but different staminas, as the workstation units only hold 2 batteries, the racks hold 4. The racks do have a slightly beefier transformer, and seem to cool better as such.

thats what i was trying to explain, thanks

 

[Michael Daly]

The 250 VA in the scenario would be capable of the same runtime as the 500 VA... but at a load of 250 VA max.

At half the power, it should run twice as long (ignoring efficiency effects). However, the ratings don't say that . Ratings of currently available models on the APC web site (which do not include the discontinued models I'm dealing with) show the opposite effect - the high power units run longer (I haven't looked at whether the modern units use the same batteries or not). However, ISTR that when I bought my units, the same thing applied.

It still sounds to me that the ratings may not match the battery's capabilities and we're seeing marketing rather than engineering.

 

[Gorankar]

You are seeing some marketing, for sure, but the guts of the things are much like psu's, they have differing; efficiencies, power output capabilities, and features.. Which all can change the actual runtime once power fails..

 

[nobody_here]

my experience with UPS's, which is alot like dealing with OneAC's and other medical approved devices (practical use, not internal design knowledge), is that just when you think you found one that has enough ass to provide what you need, step up to the next model, to get a really good one, you need to spend alot of money to get one you will be satisfied with

 

[Michael Daly]

step up to the next model, to get a really good one, you need to spend alot of money to get one you will be satisfied with

The two I bought were fine for the P3 computers they supported, but now that I've upgraded to C2D, they are barely powerful enough (though the video card's the real culprit on hogging power). They won't run long, just enough for a short wait and then a graceful shutdown.

 

[Bones]

Now the battery capacity is the number one determinant of the capability of a UPS

Not true. Battery capacity determines runtime, not the power delivery capability of the unit. The design of the inverter section is the primary constraint. Economy of scale would dictate using one type of battery for as many models as possible.