Nut upsdev - Jan 2009 - Questions on the state of the UPS market

As previously noted, I need to replace a UPS and want to do my 
product research in public so others can benefit.  The information
I elicit on this thread will be merged into the UPS-HOWTO.

I went to my local computer-equiuipment big-box store, a place called
MicroCenter in Ardmore, Pennsylvania.  I looked at the range of "UPS"
devices they sell and was *completely* confused.  

Bear in mind as I ask these questions that whaty I'm looking at, and
focusing on in the HOWTO, is consumer-grade systems in the $70-$200
range.  The ones available at MicroCenter seem mainly to be from 
APC, CyberPower and Belkin.

1. What's a "Battery Backup"?

One major source of my confusion was that vendors have changed, and
apparently dumbed down, the marketing terminology they use.  Everything
I saw was labeled "Battery Backup".  The term "UPS" seems to
have been
abandoned, though it is still visible in the model numbers in the
pictures on the boxes.

The source of my confusion is this.  I learned years ago to
distinguish between three categories of product:

1. Line conditioners (LCs) and surge suppressors.  The are just spike
filters, with no battery.

2. SPS = Standby power supply.  These normally filter mains power,
switching to a battery when the mains have a dropout.

3. UPS = Uninterruptible Power Supply.  These continuuosly feed power
to a battery, which discharges continuously to run the equipment.
When the mains go down, the battery stops charging. 

My problem is this: The way these products are now labeled, I
could not work out a way to tell which are which. Some look so
small that they almost have to be mere line conditoners, because
there;s no room in the case for a serious battery pack.  Others
could be SPS or UPS devices, but I can't tell which.  All are now
just labeled "Battery Backups"!

1a: Does anyone have good heuristics for telling the LCs, SPSes,
and UPSes apart based on the packaging or the specs visible on them?

When I last seriously examined the market (mid-2005), SPS designs
appeared to be on their way out because the switching electronics for
full UPS operation were dropping in cost fast enough to make SPS
designs a pointless economy.  In the 2005 and 2007 revisions of the
UPS HOWTO, I must have believed SPSes were one with the dust of
history, because I didn't mention them anywhere.

I'd still believe that, except that it's 2009 and I saw at Ardmore
that APC is still selling not only units with serial-port interfaces
but units that I know for a fact have the old-fashioned single-pin
dumb interface.  And if they're still selling *that* kind of obsolete
crap, I have to think maybe there are still SPSes in the world.

1b: Is the SPS in fact dead as a technical category?  If not, why not?

Oh, and this, too:

1c: RS232C, on consumer devices, in 2009?  Ferfuckssake, *why*? 

It's not like USB chips are expensive or anything. I know all about
this from GPS-land, actually; pl2303s are so cheap that even if the
vendors wanted to retread their RS232 designs, the cost of goods to
refit them with USB-to-serial conversion is close to zip.  Does anyone
have a clue why this interface type didn't die five years ago?
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>

It will be of little avail to the people, that the laws are made by
men of their own choice, if the laws be so voluminous that they cannot
be read, or so incoherent that they cannot be understood; if they be
repealed or revised before they are promulgated, or undergo such
incessant changes that no man, who knows what the law is to-day, can
guess what it will be to-morrow. Law is defined to be a rule of
action; but how can that be a rule, which is little known, and less
fixed?	-- James Madison, Federalist Papers 62

On Thu, Jan 15, 2009 at 07:35:02PM -0500, Eric S. Raymond
wrote:
> The source of my confusion is this.  I learned years ago to
> distinguish between three categories of product:
> 
> 1. Line conditioners (LCs) and surge suppressors.  The are just spike
> filters, with no battery.
> 
> 2. SPS = Standby power supply.  These normally filter mains power,
> switching to a battery when the mains have a dropout.
> 
> 3. UPS = Uninterruptible Power Supply.  These continuuosly feed power
> to a battery, which discharges continuously to run the equipment.
> When the mains go down, the battery stops charging. 
> 
> My problem is this: The way these products are now labeled, I
> could not work out a way to tell which are which. Some look so
> small that they almost have to be mere line conditoners, because
> there;s no room in the case for a serious battery pack.  Others
> could be SPS or UPS devices, but I can't tell which.  All are now
> just labeled "Battery Backups"!
>
> 1a: Does anyone have good heuristics for telling the LCs, SPSes,
> and UPSes apart based on the packaging or the specs visible on them?
These categorizations are still useful today, although your terminology
is different.

If they have a battery, they are #2 or #3. If not, they are #1.

Some of the fancier ones in category #2 are "line-interactive", which
try to buck or boost voltage to maintain output compliance without
going on battery. But they still pass whatever hiccups get through
the filter to your equipment. You may or may not see any that do this
for under $200. They'll use words like "line-interactive",
"buck/boost",
"AVR", etc., in their specs.

UPSs of type #3 are commonly referred to as "online" or
"double-conversion". Good luck getting anything like that for $200.
APC doesn't even have one in their lineup (as far as I can tell, the
entire Smart-UPS and Back-UPS line is #2).
> When I last seriously examined the market (mid-2005), SPS designs
> appeared to be on their way out because the switching electronics for
> full UPS operation were dropping in cost fast enough to make SPS
> designs a pointless economy.  In the 2005 and 2007 revisions of the
> UPS HOWTO, I must have believed SPSes were one with the dust of
> history, because I didn't mention them anywhere.
Unfortunately they'll always be cheaper to make, and more compact.
Since SPSs pass a fixed amount of energy through their inverter,
they can get away with using a block of metal for a heat sink, instead
of using active cooling.

(This is a big reason not to hack external batteries onto a UPS that
isn't designed to attach to them.)
> I'd still believe that, except that it's 2009 and I saw at Ardmore
> that APC is still selling not only units with serial-port interfaces
> but units that I know for a fact have the old-fashioned single-pin
> dumb interface.  And if they're still selling *that* kind of obsolete
> crap, I have to think maybe there are still SPSes in the world.
>
> 1b: Is the SPS in fact dead as a technical category?  If not, why not?
I'd say it's more pervasive now than in 2005. Price/profits/ignorance.
> Oh, and this, too:
> 
> 1c: RS232C, on consumer devices, in 2009?  Ferfuckssake, *why*? 
> 
> It's not like USB chips are expensive or anything. I know all about
> this from GPS-land, actually; pl2303s are so cheap that even if the
> vendors wanted to retread their RS232 designs, the cost of goods to
> refit them with USB-to-serial conversion is close to zip.  Does anyone
> have a clue why this interface type didn't die five years ago?
Because the stuff they're currently selling is based on 5+ year old
designs. Same reason why if you buy an alarm system or fire system,
you get, among other things, a circuit board with gobs of discrete
components on it.

Ethernet interfaces are similarly cheap (< $3). Unfortunately, the
products weren't initially designed with them in mind, so what you
get for your $100-$300 is a computer on a card that has an ethernet
port on the back.
-- 
Robert Woodcock - rcw at debian.org
"Obscenity is whatever happens to shock some elderly and ignorant
magistrate."
	-- Bertrand Russell

Citeren Robert Woodcock <rcw at debian.org>:

[...]
> Some of the fancier ones in category #2 are "line-interactive",
which
> try to buck or boost voltage to maintain output compliance without
> going on battery. But they still pass whatever hiccups get through
> the filter to your equipment. You may or may not see any that do this
> for under $200. They'll use words like "line-interactive",
"buck/boost",
> "AVR", etc., in their specs.
Most (if not all) consumer grade UPS devices on the market today are  
"line-interactive", the "off-line" versions are getting
rare. Even in
regions with rock-steady mains supplies, where the risk of brown-outs  
is non-existant, you won't find many without AVR. The reason is  
probably that this is an incredibly cheap function to add to an  
"off-line" UPS. In all units that I have examined, the same  
transformer that is used for the inverter is used for the battery  
charger and AVR function. If there is a micro-controller on board, all  
it takes to add AVR to a typical "off-line" UPS is one or two  
additional relays (and these are dirt cheap if you buy them in  
volume). You will find offers for 500 - 700 VA devices for under US$  
50 already.

[...]
>> 1b: Is the SPS in fact dead as a technical category?  If not, why not?
>
> I'd say it's more pervasive now than in 2005.
Price/profits/ignorance.
The only real disadvantage of the "off-line" and
"line-interactive"
topology, is that you have no indication about the correct operation  
of the inverter and switch-over relays until you need them.  
Switch-over times (2 - 10 ms) that are commonly mentioned as a  
disadvantage of this topology are a non-issue for switched mode power  
supplies found in virtually every device that will be connected to it.  
These are well within the range that switched mode power supplies must  
be able to cope with in everyday life. I really doubt the benefits of  
the "on-line" topology outweigh the disadvantages for consumer use,  
like lower efficiency and usually the need for active cooling (fans).  
For most SOHO applications, this topology will be just fine and I  
don't see this changing anytime soon.

Best regards, Arjen
-- 
Please keep list traffic on the list