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UPS runtime



 
 
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  #1  
Old April 1st 20, 04:31 AM posted to microsoft.public.windowsxp.general
Andy[_16_]
external usenet poster
 
Posts: 337
Default UPS runtime

I would like to calculate the approx runtime for my UPS.

I did a search, but found conflicting formulas.

12 volt
18 Ah

Total use of computer, monitor, and router is about
200 watts.

Thanks.
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  #2  
Old April 1st 20, 07:07 AM posted to microsoft.public.windowsxp.general
Jeff Barnett[_2_]
external usenet poster
 
Posts: 298
Default UPS runtime

Andy wrote on 3/31/2020 9:31 PM:
I would like to calculate the approx runtime for my UPS.

I did a search, but found conflicting formulas.

12 volt
18 Ah

Total use of computer, monitor, and router is about
200 watts.


The simplest and most efficient way is to plug two lamps with 100 watt
bulbs into your UPS and unplug everything else. Next unplug the UPS and
note the time. When the bulbs start to fade, the up time is calculated
by again noting the time and subtracting.

The use of engineering formulas isn't very accurate. There are a bunch
of highly nonlinear factors at play especially near situations were the
battery is almost used up. I think that even UPS manufactures supplement
theory with pull-the-plug-under-known load tests. Of course there loads
are more accurately known than the light bulbs I suggested but you'll
get a reasonable estimate fairly quickly.
--
Jeff Barnett
  #3  
Old April 1st 20, 09:07 AM posted to microsoft.public.windowsxp.general
R.Wieser
external usenet poster
 
Posts: 1,302
Default UPS runtime

Andy,

I did a search, but found conflicting formulas.

12 volt
18 Ah


Neither is a formule, just some numbers. Just for the record, next time
please include those formulas. They simply might include factors that are
outside of a quick calculation (which we could than point out to you).

But, onto the quick calculation:

12 volt times 18 Ah = 216 watt-hour.

216 watt-hour divided by 200 watts = a few minutes more than an hour

Than again, that ignores any kind of conversion losses, the fact that when
the battery goes near empty its voltage will drop (possibly causing the UPS
to cut out early), and that VA's are not the same as watts. YMMV.

Regards,
Rudy Wieser


  #4  
Old April 1st 20, 09:54 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default UPS runtime

Andy wrote:
I would like to calculate the approx runtime for my UPS.

I did a search, but found conflicting formulas.

12 volt
18 Ah

Total use of computer, monitor, and router is about
200 watts.

Thanks.


To start with, you can characterize the load better,
with a Kill-O-Watt power meter. They're cheap and
reusable for all sorts of projects.

(Model has "Watts" and "VA")
http://www.p3international.com/products/p4400.html

For example, my PC might range from 96W to 370W.
The 370W would be with Furmark and Prime95 running.

The UPS will not drain the battery flat. It has
a cutoff threshold it uses. The battery spec of 18Ah,
should be taken with a grain of salt. It does not
take too many cycles of draining those
batteries flat, to damage them. By keeping that
in mind, I was able to get ten years out of my battery.

Generally speaking, you should use the cabling
interface provided with the UPS, to automatically
shut down the PC cleanly when the power fails.

It would take a pretty large rack of batteries, to
make riding out all power outages possible. A Tesla
powerwall (~$10K magnitude) is one pre-packaged way
to do it. The longest conventional power failure
I've had here, was 24 hours, for a relatively minor
issue. The longest unconventional failure might have
been three days (nuclear reactors all scrammed). During
the ice storm more than ten years ago, some rural sites
were without power for two weeks. Maybe a $100K worth
of Powerwalls could handle that. At some point, it
becomes absurd to prop up the PC :-)

Paul
  #5  
Old April 1st 20, 10:21 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default UPS runtime

R.Wieser wrote:
Andy,

I did a search, but found conflicting formulas.

12 volt
18 Ah


Neither is a formule, just some numbers. Just for the record, next time
please include those formulas. They simply might include factors that are
outside of a quick calculation (which we could than point out to you).

But, onto the quick calculation:

12 volt times 18 Ah = 216 watt-hour.

216 watt-hour divided by 200 watts = a few minutes more than an hour

Than again, that ignores any kind of conversion losses, the fact that when
the battery goes near empty its voltage will drop (possibly causing the UPS
to cut out early), and that VA's are not the same as watts. YMMV.

Regards,
Rudy Wieser


With modern "Active PFC" ATX supplies, the power factor is around 0.99
or so. This means that roughly "VA equals Watts" on those.

With the older supplies, the PF was around 0.7 or 0.65 or so,
meaning a Kill-O-Watt meter might come in handy for characterizing
the load. The Kill-O-Watt meter is good enough at what it
does, to nail the "off" power (like when the PC sleeps).
Many other measurement methods can be off by a factor
of ten (when you believe them). For example, using the
Kill-O-Watt, my machine with 8 DIMMs draws 7.5W at S3 sleep,
and the machine with 4 DIMMs draws 5W at S3 sleep. If the
8 DIMM machine is in Soft Off state, power drops to 1.3W and
some of that is USB devices on 5VSB.

Some UPS do not behave well, when on battery and driving
extremely light loads. Throwing a couple 3W lights
onto the UPS, might keep it running with such a light load.
(Preferably 3W incandescent, or even power resistors, if
you have the skills to wire some of the correct value up.)
If your UPS continues to run down to zero load, then... great :-)

And some UPS, if you switch them off using the switch, then
switch them on, they won't go back onto battery. They're refuse
to do anything until the power comes back. If you were thinking
"I'll just switch this off so in an hours time I can do X",
they don't necessarily accept your request when asked. They
can be temperamental.

Paul
  #6  
Old April 1st 20, 10:59 AM posted to microsoft.public.windowsxp.general
Andy[_16_]
external usenet poster
 
Posts: 337
Default UPS runtime

On Wednesday, April 1, 2020 at 3:08:08 AM UTC-5, R.Wieser wrote:
Andy,

I did a search, but found conflicting formulas.

12 volt
18 Ah


Neither is a formule, just some numbers. Just for the record, next time
please include those formulas. They simply might include factors that are
outside of a quick calculation (which we could than point out to you).

But, onto the quick calculation:

12 volt times 18 Ah = 216 watt-hour.

216 watt-hour divided by 200 watts = a few minutes more than an hour

Than again, that ignores any kind of conversion losses, the fact that when
the battery goes near empty its voltage will drop (possibly causing the UPS
to cut out early), and that VA's are not the same as watts. YMMV.

Regards,
Rudy Wieser


Thanks.

Andy
  #7  
Old April 1st 20, 11:00 AM posted to microsoft.public.windowsxp.general
Andy[_16_]
external usenet poster
 
Posts: 337
Default UPS runtime

On Wednesday, April 1, 2020 at 1:07:39 AM UTC-5, Jeff Barnett wrote:
Andy wrote on 3/31/2020 9:31 PM:
I would like to calculate the approx runtime for my UPS.

I did a search, but found conflicting formulas.

12 volt
18 Ah

Total use of computer, monitor, and router is about
200 watts.


The simplest and most efficient way is to plug two lamps with 100 watt
bulbs into your UPS and unplug everything else. Next unplug the UPS and
note the time. When the bulbs start to fade, the up time is calculated
by again noting the time and subtracting.

The use of engineering formulas isn't very accurate. There are a bunch
of highly nonlinear factors at play especially near situations were the
battery is almost used up. I think that even UPS manufactures supplement
theory with pull-the-plug-under-known load tests. Of course there loads
are more accurately known than the light bulbs I suggested but you'll
get a reasonable estimate fairly quickly.
--
Jeff Barnett


That's one way. Would need to wear some ear plugs to avoid listening to all those beeps that occur every minute.

:-)

Andy
  #8  
Old April 1st 20, 11:02 AM posted to microsoft.public.windowsxp.general
Andy[_16_]
external usenet poster
 
Posts: 337
Default UPS runtime

On Wednesday, April 1, 2020 at 3:54:32 AM UTC-5, Paul wrote:
Andy wrote:
I would like to calculate the approx runtime for my UPS.

I did a search, but found conflicting formulas.

12 volt
18 Ah

Total use of computer, monitor, and router is about
200 watts.

Thanks.


To start with, you can characterize the load better,
with a Kill-O-Watt power meter. They're cheap and
reusable for all sorts of projects.

(Model has "Watts" and "VA")
http://www.p3international.com/products/p4400.html

For example, my PC might range from 96W to 370W.
The 370W would be with Furmark and Prime95 running.

The UPS will not drain the battery flat. It has
a cutoff threshold it uses. The battery spec of 18Ah,
should be taken with a grain of salt. It does not
take too many cycles of draining those
batteries flat, to damage them. By keeping that
in mind, I was able to get ten years out of my battery.

Generally speaking, you should use the cabling
interface provided with the UPS, to automatically
shut down the PC cleanly when the power fails.

It would take a pretty large rack of batteries, to
make riding out all power outages possible. A Tesla
powerwall (~$10K magnitude) is one pre-packaged way
to do it. The longest conventional power failure
I've had here, was 24 hours, for a relatively minor
issue. The longest unconventional failure might have
been three days (nuclear reactors all scrammed). During
the ice storm more than ten years ago, some rural sites
were without power for two weeks. Maybe a $100K worth
of Powerwalls could handle that. At some point, it
becomes absurd to prop up the PC :-)

Paul


I used a watt o meter to come up with the usage figures.

Andy
  #9  
Old April 1st 20, 11:06 AM posted to microsoft.public.windowsxp.general
Andy[_16_]
external usenet poster
 
Posts: 337
Default UPS runtime

On Wednesday, April 1, 2020 at 4:21:26 AM UTC-5, Paul wrote:
R.Wieser wrote:
Andy,

I did a search, but found conflicting formulas.

12 volt
18 Ah


Neither is a formule, just some numbers. Just for the record, next time
please include those formulas. They simply might include factors that are
outside of a quick calculation (which we could than point out to you).

But, onto the quick calculation:

12 volt times 18 Ah = 216 watt-hour.

216 watt-hour divided by 200 watts = a few minutes more than an hour

Than again, that ignores any kind of conversion losses, the fact that when
the battery goes near empty its voltage will drop (possibly causing the UPS
to cut out early), and that VA's are not the same as watts. YMMV.

Regards,
Rudy Wieser


With modern "Active PFC" ATX supplies, the power factor is around 0.99
or so. This means that roughly "VA equals Watts" on those.

With the older supplies, the PF was around 0.7 or 0.65 or so,
meaning a Kill-O-Watt meter might come in handy for characterizing
the load. The Kill-O-Watt meter is good enough at what it
does, to nail the "off" power (like when the PC sleeps).
Many other measurement methods can be off by a factor
of ten (when you believe them). For example, using the
Kill-O-Watt, my machine with 8 DIMMs draws 7.5W at S3 sleep,
and the machine with 4 DIMMs draws 5W at S3 sleep. If the
8 DIMM machine is in Soft Off state, power drops to 1.3W and
some of that is USB devices on 5VSB.

Some UPS do not behave well, when on battery and driving
extremely light loads. Throwing a couple 3W lights
onto the UPS, might keep it running with such a light load.
(Preferably 3W incandescent, or even power resistors, if
you have the skills to wire some of the correct value up.)
If your UPS continues to run down to zero load, then... great :-)

And some UPS, if you switch them off using the switch, then
switch them on, they won't go back onto battery. They're refuse
to do anything until the power comes back. If you were thinking
"I'll just switch this off so in an hours time I can do X",
they don't necessarily accept your request when asked. They
can be temperamental.

Paul


I installed software for my UPS as well as connected a cable from my computer to my UPS.

It said Time to Empty is 40 minutes.

I have periodic power outages, but they usually only last a few seconds to a few minutes.

Andy
  #10  
Old April 2nd 20, 01:06 AM posted to microsoft.public.windowsxp.general
J. P. Gilliver (John)[_7_]
external usenet poster
 
Posts: 603
Default UPS runtime

On Wed, 1 Apr 2020 at 04:54:27, Paul wrote:
[]
It would take a pretty large rack of batteries, to
make riding out all power outages possible. A Tesla
powerwall (~$10K magnitude) is one pre-packaged way
to do it. The longest conventional power failure
I've had here, was 24 hours, for a relatively minor
issue. The longest unconventional failure might have
been three days (nuclear reactors all scrammed). During
the ice storm more than ten years ago, some rural sites
were without power for two weeks. Maybe a $100K worth
of Powerwalls could handle that. At some point, it
becomes absurd to prop up the PC :-)

Paul


There comes a point where a generator becomes economic. OK, you've got
to have fuel for it, but the energy density ... Though you've also
(assuming you truly want the U of UPS) got to switch over while you've
still got enough power to start it, and a way to instigate that.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

After I'm dead I'd rather have people ask why I have no monument than why I
have one. -Cato the Elder, statesman, soldier, and writer (234-149 BCE)
  #11  
Old April 2nd 20, 10:24 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default UPS runtime

J. P. Gilliver (John) wrote:
On Wed, 1 Apr 2020 at 04:54:27, Paul wrote:
[]
It would take a pretty large rack of batteries, to
make riding out all power outages possible. A Tesla
powerwall (~$10K magnitude) is one pre-packaged way
to do it. The longest conventional power failure
I've had here, was 24 hours, for a relatively minor
issue. The longest unconventional failure might have
been three days (nuclear reactors all scrammed). During
the ice storm more than ten years ago, some rural sites
were without power for two weeks. Maybe a $100K worth
of Powerwalls could handle that. At some point, it
becomes absurd to prop up the PC :-)

Paul


There comes a point where a generator becomes economic. OK, you've got
to have fuel for it, but the energy density ... Though you've also
(assuming you truly want the U of UPS) got to switch over while you've
still got enough power to start it, and a way to instigate that.


This is true.

I hate gas, which is why I don't think in those terms.
It's keeping them starting, keeping them running
that bothers me.

You might convince me, if the device ran off natural
gas, as then there'd be no fuel injection scheme,
I'd just have to change the oil (I can do that),
put in a new sparkplug at some point, and that
would make a palatable solution. AFAIK, the
natural gas network stays up during power
failures.

When I was a teenager, I pulled the starter cord
so many times on our gas lawnmower, I snapped the
cord on it :-) These are the experiences I remember.
I would need a "significant incentive" to think
that way :-) My multiple attempts to fix carbureted
devices has left a bad taste in my mouth (probably
the taste of gasoline). Needle valves and all that
jazz. I probably need to take a "small engine" course.

Paul
  #12  
Old April 2nd 20, 05:14 PM posted to microsoft.public.windowsxp.general
J. P. Gilliver (John)[_7_]
external usenet poster
 
Posts: 603
Default UPS runtime

On Thu, 2 Apr 2020 at 05:24:26, Paul wrote:
J. P. Gilliver (John) wrote:
On Wed, 1 Apr 2020 at 04:54:27, Paul wrote:
[]
It would take a pretty large rack of batteries, to
make riding out all power outages possible. A Tesla
powerwall (~$10K magnitude) is one pre-packaged way


(Someone pointed me at a link yesterday to electric Tornados [the
fighter aircraft]. I twigged more or less immediately - no way current
technology could do a fighter, small passenger plane maybe - even before
I got to them having to sometimes fly inverted to make sure the special
USB charging cables ...)
[]
of Powerwalls could handle that. At some point, it
becomes absurd to prop up the PC :-)

Paul

There comes a point where a generator becomes economic. OK, you've
got to have fuel for it, but the energy density ... Though you've
also (assuming you truly want the U of UPS) got to switch over while
you've still got enough power to start it, and a way to instigate that.


This is true.

I hate gas, which is why I don't think in those terms.

(We call it Petrol, of course.)
It's keeping them starting, keeping them running
that bothers me.

You might convince me, if the device ran off natural
gas, as then there'd be no fuel injection scheme,
I'd just have to change the oil (I can do that),
put in a new sparkplug at some point, and that
would make a palatable solution. AFAIK, the
natural gas network stays up during power
failures.


Never thought of that! Yes, it has some reserve capacity (tanks with
heavy lids to keep the pressure up), and probably has non-electric pumps
to do so too.

When I was a teenager, I pulled the starter cord
so many times on our gas lawnmower, I snapped the
cord on it :-) These are the experiences I remember.
I would need a "significant incentive" to think
that way :-) My multiple attempts to fix carbureted
devices has left a bad taste in my mouth (probably
the taste of gasoline). Needle valves and all that
jazz. I probably need to take a "small engine" course.

Paul


Diesels are a lot simpler, though I'm not sure there are very small
ones. (I once had reason to see the backup generator at one of my
employers: it wouldn't have been out of place in a small freighter!)
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

WANTED, Dead AND Alive: Schrodinger's Cat
  #13  
Old April 2nd 20, 05:54 PM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default UPS runtime

J. P. Gilliver (John) wrote:
On Thu, 2 Apr 2020 at 05:24:26, Paul wrote:
J. P. Gilliver (John) wrote:
On Wed, 1 Apr 2020 at 04:54:27, Paul wrote:
[]
It would take a pretty large rack of batteries, to
make riding out all power outages possible. A Tesla
powerwall (~$10K magnitude) is one pre-packaged way


(Someone pointed me at a link yesterday to electric Tornados [the
fighter aircraft]. I twigged more or less immediately - no way current
technology could do a fighter, small passenger plane maybe - even before
I got to them having to sometimes fly inverted to make sure the special
USB charging cables ...)
[]
of Powerwalls could handle that. At some point, it
becomes absurd to prop up the PC :-)

Paul
There comes a point where a generator becomes economic. OK, you've
got to have fuel for it, but the energy density ... Though you've
also (assuming you truly want the U of UPS) got to switch over while
you've still got enough power to start it, and a way to instigate that.


This is true.

I hate gas, which is why I don't think in those terms.

(We call it Petrol, of course.)
It's keeping them starting, keeping them running
that bothers me.

You might convince me, if the device ran off natural
gas, as then there'd be no fuel injection scheme,
I'd just have to change the oil (I can do that),
put in a new sparkplug at some point, and that
would make a palatable solution. AFAIK, the
natural gas network stays up during power
failures.


Never thought of that! Yes, it has some reserve capacity (tanks with
heavy lids to keep the pressure up), and probably has non-electric pumps
to do so too.


I can't honestly say I've seen any natural gas infrastructure
in town here. I don't know where the reservoir is, if one
is present. Never seem to have a problem with pressure.

When they have natural gas pumping stations, there's usually
a good deal of clearance around them. A buddy at work, used to
work on stuff like that. And he said, sometimes he'd drive to
a site in his pickup, and there'd be a crater in the ground,
where the pumping station used to be :-) And that's why it's better
not knowing where stuff like that is located. It would have
been interesting, to know where he parked the pickup...
how far away, and how fast he could run.

Paul
 




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