Kill-o-watt meter used on computer UPS - bad readings?
Bob F
into my Kill-o-watt meter. After the UPS quit beeping after power was restored,
the meter shows 7-11 watts being consumed by the UPS feeding the computer, which
is way less than the computer (quad core core-duo processor) uses.
Does the killowatt have a problem reading accurately with UPS units?
danny burstein
from the battery.
Let it go for an an hour or three and see what happens.
- to directly answer your question, I've never had problems
for more than a couple of minutes with UPS/KAW reading.
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
m II
èqualize` the batteries to attempt to fast replace the lost energy
storage charge.
As the previous responder posted let it sit for a while and stabilize
charges.
---------------
"Bob F" wrote in message news:j58nbe$aqt$1...@dont-email.me...
Jim Wilkins
"Bob F" <bobn...@gmail.com> wrote in message
news:j58nbe$aqt$1...@dont-email.me...
incandescent lamp. It shows 111V 55W and 129V 59W. I see odd readings on the
input of a UPS too, but they have always been higher than expected.
jsw
danny burstein
>> Does the killowatt have a problem reading accurately with UPS units?
>I just checked a KAW P4400 with two stepped square wave inverters and a 60W
>incandescent lamp. It shows 111V 55W and 129V 59W. I see odd readings on the
>input of a UPS too, but they have always been higher than expected.
Have you had a chance to check the power draw
of that "60 watt" lamp when it's plugged directly
into the outlet (that is, no UPS inline)?
Jim Wilkins
"danny burstein" <dan...@panix.com> wrote in message
news:j5a1b8$nv3$1...@reader1.panix.com...
> writes:
>
>>> Does the killowatt have a problem reading accurately with UPS units?
>
>>I just checked a KAW P4400 with two stepped square wave inverters and a
>>60W
>>incandescent lamp. It shows 111V 55W and 129V 59W. I see odd readings on
>>the
>>input of a UPS too, but they have always been higher than expected.
>
> Have you had a chance to check the power draw
> of that "60 watt" lamp when it's plugged directly
> into the outlet (that is, no UPS inline)?
course, and probably the age of the bulb as tungsten evaporates off the
filament. Typically this one reads 55W at 120V. This morning the line is at
122.6V and the bulb draws 58W.
I don't have another way to measure AC power that's significantly more
accurate than a KAW. Except for one old Amprobe my clamp-on current meters
pretty much agree with it. An in-cal analog oscilloscope with voltage and
current probe is typically assumed to be accurate to ~3%, and mine are long
out of calibration.
jsw
Johny B Good
wrote:
of an APC SmartUPS 700, higher than the expected 20W maintenance load
(fully charged battery, or, indeed, no battery at all)[1] plus the load,
say 100W, giving a reading higher than the expected sum total figure of
120W?
I must admit that I haven't made such measurements to check on how much
greater the cost of supplying a PC with mains power is over and above the
simple no load maintenance power draw of the UPS in question (when its
battery is fully charged) plus load wattage. I suppose there could be a
small additional loss on top of the no load maintenance 'loss' when a load
is drawing current through the filtering circuitry of the UPS but I would
have expected this to be an insignificant loss unless the UPS was equipped
with a buck/boost transformer function to avoid transferring to battery
power during modest sags and dips and it happened to be correcting for a
sag in line voltage at the time.
[1] The maintenance load figure is the one item that the UPS manufacturers
seem to be extremely reluctant to actually include in their
specifications. It's a figure I've never been able to find in _any_ UPS
published specifications that I have looked at (and I've perused quite
few).
I suppose this is an inherited 'Mind Set' harking back to the days of
cheap power but those days have long since passed into history. Now that
the cost of power is a much greater factor, not just to the home user but
also to large data centres where they can be using several hundred KWH per
day, it is rather surprising that the UPS manufacturers are still treating
the maintenance figure as a 'dirty little secret' never to be openly
disclosed to their customers.
FYI, I can give you maintenance figures for the following APC units that
I own:
SmartUPS 2000 32 to 35 watts
SmartUPS 700 20 watts exactly
Backups 500 3 watts
In all cases, this is the power drawn when their respective batteries are
in the fully charged condition (which, in the case of the SmartUPS 700 is
the same as with the battery disconnected - it supports hot swapping of
its battery pack).
The measurements were all made using a Metrawatt analogue wattmeter set
to the 100v and 1A range settings (100 watt FSD range) on a 240v 50Hz UK
supply voltage. The 100v setting might seem an odd choice for a 240v
supply but I wanted to measure on the lowest range scale possible and the
moving coil part of the circuit has no iron to saturate and will typically
be capable of coping with a tenfold overload without risk of burnout
(although the multiplier resistor may not be so lucky with _that_ level of
overload). It has coped quite nicely with the 20% overload over and above
the built in factor of two limit for the selected voltage range during the
last 15 years or so of 24/7 connection to the 240v mains supply.
HTH & HAND
--
Regards JB Good
cl...@snyder.on.ca
sitting on my "Kill-a-watt" type unit right now, and it is fluctuating
between 0 and 61 watts, constantly changing. On the AMPS range, it is
pretty steady at 0.72 to 0.73 amps - which at unity power factor would
be 84 watts (117 volt line voltage) and there is NO WAY it is
dissipating 84 watts (or even 62) of power as heat. The unit isn't 2
dgrees F above ambient, and it's been running for several weeks.
I suspect there is some strangeness in the power factor throwing the
unit off.
Putting a hologen lamp on the kill-a-watt it reads 266 watts - plugged
into the UPS, it reads 339 to 334 - which would indicate the
"overhead" of the UPS is ABOUT 70 - 75 watts.
Again, I'm SURE it is reading considerably high - but the fluctuation
is significantly less than when it is running at no load. a 40 watt
bulb in the case would make it SIGNIFICANTLY hotter than the operating
UPS.
Bob F
the same results. It shows 6 watts with the computer connected, and 9 with it
on. The killowatt just doesn't see the computer.
Johny B Good
> On Tue, 20 Sep 2011 17:14:15 +0100, "Johny B Good"
> <inv...@ntlworld.com> wrote:
>
>
>
> I've got a fully charged Powereware Prestige 1000 va online UPS
> sitting on my "Kill-a-watt" type unit right now, and it is fluctuating
> between 0 and 61 watts, constantly changing. On the AMPS range, it is
> pretty steady at 0.72 to 0.73 amps - which at unity power factor would
> be 84 watts (117 volt line voltage) and there is NO WAY it is
> dissipating 84 watts (or even 62) of power as heat. The unit isn't 2
> dgrees F above ambient, and it's been running for several weeks.
>
> I suspect there is some strangeness in the power factor throwing the
> unit off.
>
> Putting a hologen lamp on the kill-a-watt it reads 266 watts - plugged
> into the UPS, it reads 339 to 334 - which would indicate the
> "overhead" of the UPS is ABOUT 70 - 75 watts.
>
> Again, I'm SURE it is reading considerably high - but the fluctuation
> is significantly less than when it is running at no load. a 40 watt
> bulb in the case would make it SIGNIFICANTLY hotter than the operating
> UPS.
your watt meter because I was rather surprised that an actual Kill-A-Watt
meter could produce such wildly inaccurate readings.
Unfortunately, a lot of the cheaper $10 units that were being sold in
WallMart or ToolMart shops a few years ago left a lot to be desired
regarding accuracy on non linear loads below the 100W mark and were
totally misleading with smaller smpsu type wallwarts where a real 6 watt
load could read either zero or some ficticious 15 to 20 watt figure. I
suspect the model of digital watt meter you're using is one such gadget.
Up until about 12 months ago, I was of the opinion that all such digital
watt meters were prone to this problem (as demonstrated by a couple of
£9.99 meters bought from our local ToolMart shop a few years back).
What changed my mind about the Kill-A-Watt meter's accuracy was my
acquiring a UK version of this meter for a couple of quid from a flea
market trader who specialises in flogging Maplin's returns. The particular
model in question being a Chinese made "Plug-In Mains Power & Energy Usage
Monitor" (as per the box description) made especially for Maplin with the
model code number of L61AQ.
<http://www.maplin.co.uk/plug-in-mains-power-and-energy-monitor-38343>
Curiously, on opening the box to look at the instruction leaflet, it
appears to be a Prodigit Electronics Co. Ltd product with the model number
of "2000MU-UK". The leaflet is quite clearly referring the meter being
sold by Maplin as an L61AQ.
The power _consumption_ of the meter itself is misquoted on the Maplin
web page as being 20W (which I've also seen misquoted as 10W in the specs
for the Kill-A-Watt P4460). The leaflet more accurately quotes this as 20
VAmax. In reality, checking it with the Metrawatt, the actual power draw,
as best as I can make out using a jeweller's loupe, is just over half a
watt.
The extremely low power factor of 0.025 is exactly what you can expect
when a simple capacitor dropper is used to produce the 5 (or possibly 12)
volt supply required of the processor /ADC chip used in these meters. When
the same circuit is used in a 120 volt device as opposed to a 240 volt
one, the VA figure is halved when delivering the same power to the digital
electronics of the meter.
Going by the PDF of the Kill-A-Watt P4460 manual, it appears to be made
by a different manufacturer using the name P3 International Corp. Since
they're physically identical, apart from the country specific socket,
these items have clearly been made in the same factory, I can only suppose
that "The Global Market Economy" has made manufacturing names as
disposable as email addresses. At the very least, you can bet your bottom
dollar that the L61AQ (aka 2000MU-UK) and the Kill-A-Watt P4460 were both
made in the same Chinese factory.
Whilst the accuracy on sub 10 watt loads is reasonable (around the +/-
15% mark), despite measuring to tenths of a watt, it simply fails to
register the 0.7W consumption of the Metrawatt when switched to the 200v
range (it shows, inaccurately, a reading of 1.7W when the Metrawatt is
switched to the 100v range - the other digital meter ( another Maplin
item, product code N67FU, that I'd bought a few months earlier at the same
flea market) displays this as 1.3W which I'm pretty confident is the more
accurate figure as it's almost twice as much as the 0.7W reading due to
the halving of the multiplier resistance in the Metrawatt when dropping
from the 200v range into the 100v range.
I've just realised that I can more accurately assess the sub 2W accuracy
of these digital meters by measuring the resistance of the MetraWatt
across the live and neutral pins (essentially measuring the voltage
multiplier resistor used on each voltage range). Rather conveniently, it
seems to be based on a notional meter sensitivity of 500 ohms per volt
since I get 50.1K, 100.7K and 247K ohms on the 100, 200 and 500 volt
ranges respectively.
Based on the voltage reading of 246.2v that I was getting from the
2000MU-UK (aka a 240v Kill-A-Watt meter) The other digital watt meter was
only over reading by 0.1W in both cases. The 1.7W reading from a 1.2W load
using the 2000MU-UK represents an error in excess of +40%.
For measuring sub 10W loads, the N67FU walks all over the 2000MU-UK in
terms of accuracy. I believe the 2000MU-UK (aka a 240v Kill-A-Watt meter)
loses out because they seem to have squandered a 4 decimal digit accuracy
to the voltage ADC instead of where such accuracy matters most, i.e. the
Current ADC.
The N67FU can only show voltage to 3 digits so it's reasonable to assume
the reason for it being able to show sub 1 watt readings with a fair
accuracy (as opposed to NO accuracy of the 2000MU-UK in this wattage
range) is that they've used the higher bit accuracy on the current sensor
ADC.
Although I wasn't as impressed by the 2000MU-UK (aka a 240v Kill-A-Watt
meter) when it came to sub 5 watt load measuring accuracy, this was only
on account I'd been even more impressed by the previously acquired N67FU
meter's accuracy in this very low power range. After my experience with
the ToolMart meter, both of these models couldn't fail to impress. ;-)
The only minor deficiency in the N67FU meter is the absence of the PF and
VA measurement functions contrary to these being specified in the list of
functions shown on the packaging. It's only a very minor concern since
it's very easy to calculate these figures, if required, from separate
voltage and current readings (which gets you a VA figure which can then be
used with the real power reading to obtain a PF figure). I have to say,
I've never felt the need to make such measurements.
The bottom line, regarding that useless watt meter of yours is that you
should replace it with an actual Kill-A-Watt (or better) meter if you want
to make reasonably accurate measurements of your computer kit's power
consumption.
cl...@snyder.on.ca
the Home Hardware company for $49 - I bought it on sale for 24.95.
Also sold at Canadian Tire. They are currently listed at 24.95 at
Canadian Tire. UPM was suject of a patent infringement case by the
manufacturer and designer of the Kill-a watt, P3 international of the
USA and Daniel Liu of Taiwan.
Johny B Good
> On Wed, 21 Sep 2011 02:52:30 +0100, "Johny B Good"
> <inv...@ntlworld.com> wrote:
>
>>
>> The bottom line, regarding that useless watt meter of yours is that you
>> should replace it with an actual Kill-A-Watt (or better) meter if you
>> want
>> to make reasonably accurate measurements of your computer kit's power
>> consumption.
>>
>> HTH & HAND
> It's a UPM EM100 Energy Meter, made in China and originally sold by
> the Home Hardware company for $49 - I bought it on sale for 24.95.
> Also sold at Canadian Tire. They are currently listed at 24.95 at
> Canadian Tire. UPM was suject of a patent infringement case by the
> manufacturer and designer of the Kill-a watt, P3 international of the
> USA and Daniel Liu of Taiwan.
I find it hard to believe that it could be infringing any of P3
International's patents.
--
Regards JB Good
Jim Wilkins
"Johny B Good" <inv...@ntlworld.com> wrote in message
news:op.v137d1elkd9x7s@fred...
>...I see odd readings on
>> input of a UPS too, but they have always been higher than expected.
>>
>
> When you say higher than expected, do you mean, for example in the case
> of an APC SmartUPS 700, higher than the expected 20W maintenance load
> (fully charged battery, or, indeed, no battery at all)[1] plus the load,
> say 100W, giving a reading higher than the expected sum total figure of
> 120W?
>
The UPS in question is a Tripplite 1050 I bought second-hand with apparently
bad batteries, which recovered nearly their full capacity after a few test
cycles.
I thought its initial power demand was ~60W but noticed a brief peak of 100W
after posting that. I had seen ~130W with a laptop plugged in and booting.
Now it makes sense.
That laptop is becoming a data logger. Yesterday I added a dual serial port
PC card to run both a Dataq DI-194RS four channel A/D and a serial-output
Radio Shack DVM. Since the meter isn't fast enough to catch inrush or
switching supply current I got some of these to use with the 194:
http://www.gmw.com/magnetic_sensors/asahi/current-sensors-HA.html
and ordered these to read thermocouples:
http://parts.digikey.com/1/parts/2004324-ic-thermocouple-a-w-comp-8msop-ad8495crmz.html
The 400MHz laptop draws only ~8W with the screen off and should run for days
from a truck battery.
jsw
T. Keating
wrote:
>I just unplugged the Belkin 1200 VA UPS powering my computer, and plugged it
>into my Kill-o-watt meter. After the UPS quit beeping after power was restored,
>the meter shows 7-11 watts being consumed by the UPS feeding the computer, which
>is way less than the computer (quad core core-duo processor) uses.
20 to 30 watts when the display is active. (powered down is different
story.)
>
>Does the killowatt have a problem reading accurately with UPS units?
>
Most fully charged UPS's will consume an extra 7 to 14 watts on a full
time basis.
Mutiply that by 4 or 5 UPS's and you've got a significant energy
wastage.
That's one reason why I've retired all UPS's except one very big
office unit(tripp lite APS-1012) connected to a deep cycle(115amp/hr,
1.4kWh) battery. (Even then, I don't leave it connected up, instead I
keep in zero power draw standby configuration with one battery
terminal disconnected until needed.).
Instead I use a laptop for most internet surfing, it's old Li-ion
battery can keep it alive for a few minutes while I connect up the Big
tripplite.
=====
B.T.W. I'm constantly looking for or building low energy consumption
battery backups for the other must have devices. (DSL router, micro
server, network switch, etc)
A couple of AA-NiMH batteries in series, a small step up dc-dc
inverter, a resistor. a cap or two, presto-done. Now the device
keeps on running for a hour or two, while the circuit adds just a few
hundred milliwatts of standby load.
As for 12 volt dc devices, I have found the "Belkin DC battery
backup" units used by AT&T universe customers to be a real gems, (AT&T
doesn't want them back after customer terminates service).
http://en-us-support.belkin.com/app/answers/detail/a_id/2662
They have about a watt of overhead and can deliver several amps(@12v)
when needed. I now use one to power my DSL modem/router.
T. Keating
>into my Kill-o-watt meter. After the UPS quit beeping after power was restored,
>the meter shows 7-11 watts being consumed by the UPS feeding the computer, which
>is way less than the computer (quad core core-duo processor) uses.
20 to 30 watts when the display is active. (powered down is different
story.)
>
>
Most fully charged UPS's will consume an extra 7 to 14 watts on a full
time basis.
Mutiply that by 4 or 5 UPS's and you've got a significant energy
wastage.
That's one reason why I've retired all UPS's except one very big
office unit(tripp lite APS-1012) connected to a deep cycle(115amp/hr,
1.4kWh) battery. (Even then, I don't leave it connected up, instead I
keep in zero power draw standby configuration with one battery
terminal disconnected until needed.).
Instead I use a laptop for most internet surfing, it's old Li-ion
battery can keep it alive for a few minutes while I connect up the Big
tripplite.
=====
B.T.W. I'm constantly looking for or building low energy consumption
battery backups for the other must have devices. (DSL router, micro
server, network switch, etc)
A couple of AA-NiMH batteries in series, a small step up dc-dc
inverter, a resistor. a cap or two, presto-done. Now the device
keeps on running for a hour or two, while the circuit adds just a few
hundred milliwatts of standby load.
As for 12 volt dc devices, I have found the "Belkin DC battery
Johny B Good
wrote:
>
I would say that's on account _you're_not_ using a Kill-o-Watt meter,
like the OP is. I, like you, ass-u-me d he was talking about a Kill A
Watt(tm) meter.
As I mentioned in a reply to another poster in this thread, I have
experience with UK version of the Kill A Watt(tm) meter and there's no way
it would behave in the manner described by the OP with regard to what is
obviously a cheap meter trying to pass itself off as a Kill A Watt(tm)
meter.
--
Regards JB Good
Bob F
Johny B Good
In that case, I rather suspect that your meter has a fault. An obvious
test would be to use it to measure resistive loads such as incandescent
tungsten filament lamps, electric kettles, electric toasters, electric
soldering irons and so on.
These are loads that have a measurable resistance which will allow you to
estimate their actual power consumption by way of a sanity check (in
addition to the rating plate or label).
Bear in mind that most electric heating elements have a modest positive
temperature coefficient of resistance so will read a little lower than
expected when cold. The exception to this is the humble tungsten filament
lamp where the postive coefficient is not so modest (multiply the cold
resistance reading by a factor of 10 if want a ball park figure estimate
of its resistance at working temperature).
--
Regards JB Good
Mho
obsolete email browser and stop using my nickname, Eric?
Maynard?....LOL all that profession about being "The Usenet Guru"
-------------
"m II" wrote in message news:4e7a...@news.x-privat.org...
cl...@snyder.on.ca
JB - even the lill-a-watt may be able to be fooled by a "digital"
power supply putting "dirty power" back out the line. I'm going to
have my UPM replaced and see if the new one has the same issue.
cl...@snyder.on.ca
wrote:
>On Mon, 19 Sep 2011 17:39:10 -0700, "Bob F" <bobn...@gmail.com>
>wrote:
>
>>I just unplugged the Belkin 1200 VA UPS powering my computer, and plugged it
>>into my Kill-o-watt meter. After the UPS quit beeping after power was restored,
>>the meter shows 7-11 watts being consumed by the UPS feeding the computer, which
>>is way less than the computer (quad core core-duo processor) uses.
>
>This statement I doubt.. Even my most energy sipping laptop consumes
>20 to 30 watts when the display is active. (powered down is different
>story.)
>
draws - not the other way around.
Johny B Good
wrote:
>
> "Johny B Good" <inv...@ntlworld.com> wrote in message
> news:op.v137d1elkd9x7s@fred...
>> On Tue, 20 Sep 2011 13:31:15 +0100, Jim Wilkins <murat...@gmail.com>
>> wrote:
>> ...I see odd readings on
>>> the
>>> input of a UPS too, but they have always been higher than expected.
>>>
>>
>> When you say higher than expected, do you mean, for example in the case
>> of an APC SmartUPS 700, higher than the expected 20W maintenance load
>> (fully charged battery, or, indeed, no battery at all)[1] plus the load,
>> say 100W, giving a reading higher than the expected sum total figure of
>> 120W?
>>
>> Regards JB Good
>
> The UPS in question is a Tripplite 1050 I bought second-hand with
> apparently
> bad batteries, which recovered nearly their full capacity after a few
> test
> cycles.
>
> I thought its initial power demand was ~60W but noticed a brief peak of
> 100W
> after posting that. I had seen ~130W with a laptop plugged in and
> booting.
> Now it makes sense.
One would hope that the 100W represents a battery re-charging demand (and
ditto for the 60W reading). One might reasonably expect a 1KVA (700W) UPS
to have a maintenance demand when the battery pack is fully charged no
higher than 30W (on a par with the SmartUPS 700's 20W maintenance
consumption compared to the VA level of protection in each case).
Actually, with a modern design of UPS one might reasonably expect a
maintenance consumption of 5W or less.
I've also got an ancient UPSonic UPS600 which I retired about 12 months
ago on discovering that its maintenance consumption had risen from its
normal 17W up to the 35W mark indicating that it had fried its second set
of batteries (2 banks of 3 by 12v 7AH dryfits) after about a 3 or 4 year
period of service.
I'd had enough by then. It still functions but it just isn't as kind to
its batteries as it could be and has no automated battery condition test
option to give you a clue as to the impending demise of the batteries. In
any case, even the normal 17W maintenance consumption was looking like a
luxury I could well do without, especially as it was supplying a second
level of UPS protection from the protected mains sockets powered by my
SmartUPS 2000 (a 2KVA 1500W unit) that I keep in the basement.
The point I'm making here is that you might want to allow that TrippLite
plenty of time to fully charge its battery and test its consumption with
nothing powered from its outlets. Since the battery pack (3 x 6V 10AH
dryfits) can be hot swapped, you can disconnect them and check whether the
maintenance consumption changes. if the battery pack is in good condition
and has fully charged, you won't see any difference (when I did this test
on the SmartUPS 700 I couldn't detect any change, and I was using an
analogue meter which can show the tiniest of changes that would be totally
lost on a digital meter).
Any noticeable drop in consumption when disconnecting the battery should
be taken as a warning of impending battery failure. To be certain that the
battery is as charged up as it can be, reconnect the battery and repeat
the test a few hours later (preferably 4 or more). If you still see the
same drop on disconnection, you can be pretty certain the battery is past
its best.
The annoying thing with that tripplight unit is its use of three 6v 10AH
batteries rather than the more usual pair of 12v 7AH batteries which are
far more widely available on account of their use in home burglar alarm
control panels. The WH ratings are very similar, 180 and 168 watt hours
respectively.
This is yet another UPS manufacturer who fails to reveal the maintenance
consumption figure for its product. The only hint of this is a reference
to "Green & high efficiency features" as being "Greater than 95%
efficiency - GREEN UPS". WTF is this supposed to mean? Can it be the
conversion efficiency of battery power into line voltage power? Perhaps
this is their rather coy way to explain why it might be consuming just
over 35W when plugged into an outlet with no load attached. Best of all,
WTF _is_ "GREEN UPS" supposed to mean exactly? My guess is that it's
simply the usual marketing BS that's so often used to sugar coat an
otherwise unpalatable fact. You might, indeed, find that the UPS does take
over 30W with the battery pack disconnected, thus revealing the marketing
BS for what it is.
To highlight the importance of "This dirty little secret", at one point I
was burning 82W in maintenance consumption from a collection of 5 UPSes
that I'd acquired at radio ham rallies over the past 20 years or so. After
retiring that Upsonic UPS600 and the SmartUPS 700 (which had also been
providing a second level of protection from the protected supply) I've now
reduced this to some 45W.
I'm using an ancient Emerson 30, my very first UPS from about 20 years
ago, to protect the Cable modem wireless router powered from a normal
mains outlet. The maintenance consumption on this is only around the 7 to
8 watt mark. Strange to say, this was the only UPS that ever got used in
anger to cover a 3 or 4 hour outage shortly after its acquisition.
Even so, what it was used for was simply to power a lamp stand with one
of those (at the time) new fangled CFLs fitted in order to provide
illumination from the half landing to light up the hallway and the stairs.
It was also handy to illuminate the upstairs toilet which allowed one of
the children to complete their school homework whilst sitting on the
toilet seat.
That event happened on a radio ham club night. On returning home about 3
hours later, The mains supply was back on and it seems the UPS had managed
to keep that 15W lamp powered right through the whole outage which ISTR
was around 4 hours in total. Since this ancient unit doesn't have a black
start function it wasn't possible to switch it on and off to maximise
battery endurance, leaving me only with the one option of shedding the
load, i.e. switching the light off.
Aside from a period of sub one second dropouts a few years back when the
local substation contactor gear was in need of an overhaul, we've never
had any other outages. Here in the UK, suburban mains supplies are very
reliable (most of the UK population lives in the 'burbs) so the desire to
protect against a once per generation outage event might seem a little bit
over the top but it's my computer kit I'm protecting. The market for UPSes
is very tiny indeed in the UK. However, there's every possibility that
this may change in the not so distant future.
>
> That laptop is becoming a data logger. Yesterday I added a dual serial
> port
> PC card to run both a Dataq DI-194RS four channel A/D and a serial-output
> Radio Shack DVM. Since the meter isn't fast enough to catch inrush or
> switching supply current I got some of these to use with the 194:
> http://www.gmw.com/magnetic_sensors/asahi/current-sensors-HA.html
> and ordered these to read thermocouples:
> http://parts.digikey.com/1/parts/2004324-ic-thermocouple-a-w-comp-8msop-ad8495crmz.html
>
> The 400MHz laptop draws only ~8W with the screen off and should run for
> days
> from a truck battery.
>
Is that using the truck battery to directly power the laptop through its
charger socket?
--
Regards JB Good
Jim Wilkins
> wrote:
>> "Johny B Good" <inv...@ntlworld.com> wrote in message
>>> ...
>> The UPS in question is a Tripplite 1050 I bought second-hand with
>> apparently bad batteries, which recovered nearly their full capacity
>> after a few test cycles.
>>
>> I thought its initial power demand was ~60W but noticed a brief peak of
>> 100W after posting that. I had seen ~130W
>> with a laptop plugged in and booting.
>> Now it makes sense.
>
> One would hope that the 100W represents a battery re-charging demand (and
> ditto for the 60W reading). One might reasonably expect a 1KVA (700W) UPS
> to have a maintenance demand when the battery pack is fully charged no
> higher than 30W (on a par with the SmartUPS 700's 20W maintenance
> consumption compared to the VA level of protection in each case).
> Actually, with a modern design of UPS one might reasonably expect a
> maintenance consumption of 5W or less.
reading and dropped to ~65W.
> The point I'm making here is that you might want to allow that TrippLite
> plenty of time to fully charge its battery and test its consumption with
> Any noticeable drop in consumption when disconnecting the battery should
> The annoying thing with that tripplight unit is its use of three 6v 10AH
> batteries rather than the more usual pair of 12v 7AH batteries which are
> far more widely available on account of their use in home burglar alarm
> control panels. The WH ratings are very similar, 180 and 168 watt hours
> respectively.
have recovered to nearly the rated Watt-Hour capacity.
> This is yet another UPS manufacturer who fails to reveal the maintenance
The fully charged Tripplite's idle power is about 17W. The batteries hold a
charge well when unplugged for months. I won't know the DC power to recharge
them until I finish the laptop data logger, -after- I fix the hydraulic pump
on my tractor and do some excavating. KAW measurements include the charger's
or lab supply's overhead.
I left it "off" (blinking) and unplugged for a week and measured 0.36 KWH
($0.05) to recharge it. I'll probably add a switch to disconnect the
batteries without removing them, and test points to measure & recharge the
batteries from a lab supply. The batteries and wires are such a tight fit
that cramming them in bent a connector tab at some point.
>
> I'm using an ancient Emerson 30, my very first UPS from about 20 years
> ago, to protect the Cable modem wireless router powered from a normal
> mains outlet. The maintenance consumption on this is only around the 7 to
> 8 watt mark. Strange to say, this was the only UPS that ever got used in
> anger to cover a 3 or 4 hour outage shortly after its acquisition.
> Aside from a period of sub one second dropouts a few years back when the
> local substation contactor gear was in need of an overhaul, we've never
> had any other outages. Here in the UK, suburban mains supplies are very
> reliable (most of the UK population lives in the 'burbs) so the desire to
> protect against a once per generation outage event might seem a little bit
> over the top but it's my computer kit I'm protecting. The market for UPSes
> is very tiny indeed in the UK. However, there's every possibility that
> this may change in the not so distant future.
idiotic traffic accidents. I've twice lost it for a week, both in midwinter.
> Is that using the truck battery to directly power the laptop through its
> charger socket?
There isn't much difference between a 12V auto/air adapter which inverts to
18V or a small 120V inverter plus the mains power supply. I haven't measured
it precisely because the computer's draw isn't steady, and I don't own a DC
current probe for the scope. The only number that matters is run time, which
is too sensitive to hard drive activity and processor + fan speed to
characterize accurately. There's no point testing it with the computer
inactive because I wouldn't waste battery power that way during a blackout.
jsw
vaughn
...>especially as it was supplying a second
> SmartUPS 2000 (a 2KVA 1500W unit) that I keep in the basement.
is a very bad idea. Think of every UPS not only as protection, but as a
potential POINT OF FAILURE. To reduce the inevitable failures, simply reduce
the number of UPSs. I suffered more than one unnecessary server outage before
the lesson sunk in. One layer of UPS "protection" is plenty!
Vaughn
Jim Wilkins
"vaughn" <vaugh...@gmail.invalid> wrote in message
news:j5hso3$gfq$1...@dont-email.me...
recording an hour or two of television unattended? One UPS will power my
recording PC for about 45 minutes. The wattage is somewhat less than half
the UPS's rating, so it might survive a longer run with an external battery.
jsw
cl...@snyder.on.ca
- some don't like squarewave input.
As for the power usage and the "kill-a-watts" units readings - I gort
a replacement for my EM100, and swings between about 33 and 40 watts
with the occaisional spike to 70 - I'll run it for a period of time
and see what the average consumption comes out to. The old unit
indicated over 60 watts, my guess is less than 35 watts. This is a
TRUE ONLINE dual conversion UPS, so it will draw significantly more
than a standby unit.
Johny B Good
wrote:
computers around the house with the "Big & Heavy"(tm) Upsonic UPS600
protecting the office/workbench PC kit and the SmartUPS 700 protecting the
"Family PC"(tm) and HiFi kit in the front room (I think I had the Emerson
30 looking after the cable modem and a wireless gateway router). When I
did add that unit to the mix, I was reluctant to retire the existing units
straight away (at least not until the SmartUPS 2000 had had a chance to
prove itself).
Initially, I didn't see the cascading of UPS protection as a reduction of
reliability, quite the contrary. Even now, the sole reason for eliminating
the Upsonic UPS600 and the APC SmartUPS 700 is simply to eliminate a 37W
maintenance loading, both from my utility bill and from the prime UPS base
load to enhance its up time in the (as it turns out)unlikely event of an
outage.
I wasn't able to put the SmartUPS 2000 directly into service (as, say a
replacement to the UPS600) since it was sold sans the battery pack base
(this model is a split unit that sits atop its matching sized battery
pack) so I had to house it in the basement on top of an otherwise
redundant battery rack I had originally set up to house two banks of
revived 225AH ex-pabx wet cells that I had been using to provide 12v shack
power. The battery rack now became home to an external battery pack made
up of four 36AH car batteries which replaced the original set of four
18AH 12v gel/AGM batteries used in the battery pack base.
That set of four 36AH automotive batteries I was using was ok for the
first 12 to 18 months until they succumbed to the "excessively benign"
maintenance charging regime when the cells started to develop symptoms of
high self discharge. It seems that automotive batteries prefer 'rough
handling' to the most considerate and kindest of treatment possible. Don't
ask me why, it "Just is". This wasn't the first time I had witnessed this
inexplicable premature failure under tightly controlled float charging
conditions.
Many years before, when I was using the home CBer's trick of float
charging a car battery off a 4 amp CB PSU as a means to power a rig (or
burner) that demanded 10 or 20 amps, I experienced the same early demise
of said battery. At the time, I just put it down to bad luck due to the
"battery reliability lottery" effect.
I think it took the same premature failure of a _second_ set of car
batteries before the awful truth finally dawned on me. Having read up on
this defficiency of automotive starter batteries, I can well and truly
claim "BTDTGTSM&TFTS!". Anyone looking to replace the original maker's
(over-priced) battery packs with cheaper alternates only has to remember
this one rule, "Any type _except_ automotive starter batteries!" The
AGM/Gel types are the primary choice but you can also use the so called
deep discharge leisure batteries and traction batteries without having to
witness the premature failure mode exhibited so nicely by the not so very
much cheaper automotive starter battery.
Anyway, I've just been looking at the battery endurance test data from
the tests I ran on the SmartUPS 2000 when I overcame the lack of the
original battery pack with that set of automotive batteries. The test date
is 1st July 2002 (note: NOT July 1st 2002 aka 7/1/02) which means I must
have acquired it at the Blackpool Radioham rally (NARSA) in March that
year.
With just the 36AH 48v battery, I got an endurance time of 287 minutes
for a 293W test load. When I repeated the test on the 4th July 2002,
anticipating a slight improvement, I only got an endurance time of 267
minutes, around a 4% reduction. This was contrary to my experience when
I'd replaced the Emerson 30's original battery pack for the very first
time with a couple of 12v 7AH alarm panel AGM batteries and only got some
40 minutes run time on the first test (barely better than the 30 odd
minutes with the old battery pack) and then some 80 odd minutes on the
second test.
When I got hold of a box of eight 12v 7AH AGM batteries at the next
rally, I set them up in two banks to create a 48v 14AH pack and ran
another test on 9th May 2003. I managed to get just over 69 minutes on a
300W load comprising a PC or two (along with a couple of UPSes which added
their own variations in loading). A second test with the car battery bank
tied in (a nominal 50AH's worth) on the following day using a lamp load of
284W produced a run time of just over 395 minutes (6 hours 35 minutes).
Now this unit isn't specified for additional battery capacity by APC so I
wouldn't care to let it run a 1.2KW load on that amount of battery without
uncrippling the fan cooling (the usual style over function design
compromise deficiency). I could quite easily improve the airflow by an
order of magnitude if I decided I was going to need that amount of power
long term from say, a 100AH or larger battery pack but at the moment I'm
down to a 25AH pack supplemented with a couple of past their best 7AH
banks, probably some 30 to 35 AH's worth by now. I'll not spend any effort
on that sort of mod unless I happen to acquire a suitably large capacity
battery at a price that even I could justify.
Regarding the issue of extending battery autonomy by connecting higher
capacity battery packs and the risk of burnout, I can also say
"BTDT>BTS!" in this case, it was a small second hand Anic 450AI I had
acquired for a song which I was using to protect a small server box. This,
rather like that Tripplite, also used non-standard batteries (i.e. they
weren't the industry standard 12v 7AH Gel batteries so commonly found in
most small UPSes and burglar alarm control panels). What it was fitted
with were a couple of rather oddball 4.5AH 12v batteries which had well
and truly expired.
Since I already had a couple of 25AH Gel batteries to hand with nothing
better to do, I pulled the midget batteries out and connected the 25AH
batteries as an external pack, using a piece of MDF to support this
frankenstein collection of parts to allow me to move it as a single unit
without having to wire up /disconnect the battery pack in situ for each
change of location.
A unit like this wasn't expected to run any longer than 2 or 3 minutes on
its maximum loading of 300W and certainly not much longer than 25 minutes
or so on the 50W loading from the small server box.
Back in June 2003, I did a full mains fail test with this unit and the
rest of the 'small' UPSes hanging off of the SmartUPS 2000 which shutdown
some 6 hours and 28 minutes into the test, placing the secondary UPSes
onto battery power. The Emerson 30 kept a 15W load going for the next 6
hours and 45 minutes, the Upsonic chose that time to reveal how badly
knackered its battery pack was by giving up just 8 minutes later and the
Anic ran its 50W load for another 5 hours 30 minutes before I restored
supply to head off an impending shutdown of the server.
The Anic survived this first extended autonomy test, a 5 1/2 hours
runtime on a load never expected to exceed a half hour at the most on the
50W load it was protecting but it died a few months later. I can't
remember exactly how long it lasted but I suspect it was less than a year
because those two 25AH batteries were joined by another pair to make up a
battery pack for the SmartUPS 2000.
This pitfall with smaller UPSes (typically smaller than 1KVA capacity)
and add on battery capacity is quite common due to the fact that the
50/60Hz transformers used are undersized (both in terms of the amount of
iron used in the core and in being underwound for the voltages used) in
order to minimise both weight and cost. IOW, the design is relying upon
the limited battery capacity to save the transformer(s) from being burnt
out during an outage whatever the protected load might be.
When you get to larger sizes of UPSes, the difference between that 2KVA
unit of mine and the later 2.2KVA ones which were designed to allow
additional battery capacity to be added to indefinitely extend run times
is more likely down to an improved cooling system rather than a more
expensive transformer.
At that size, the difference in transformers designed to operate safely
for as long as 7 1/2 hours on a very light load (35W) with the built in
battery pack and one that will run continuously at full load with a vastly
oversized battery are slight enough that it's just simply a matter of
effective cooling for the same undersized transformers. I rather suspect
that that is the case with APC since a simple change to the fan cooling is
a much cheaper option than replacing expensive transformers with even more
expensive and heavier ones.
Getting back on topic, one possible difficulty in measuring power demand
on a UPS with a digital watt meter could be an excess of capacitive
loading (which is certainly the case as far as the SmartUPS 2000 is
concerned - so much so that it caused a 230v 2.8KVA petrol generator to go
overvolt to the tune of 275 v - the regulation on the conventional AC
generator goes to pot with even modest amounts of capacitive loading).
With this in mind, I'm going to test consumption on the SmartUPS 2000
using the digital meters to compare against the readings from the analogue
meter as soon as I get the chance. I'll post back my findings to this
thread once I've finshed making those measurements.
--
Regards JB Good
Johny B Good
wrote:
>
connected, please take note of my experience regarding excess battery
capacity (admittedly an extreme case with a 5 1/2 fold increase over what
the designers had assumed was tolerable). You can probably get away with a
50% boost (which might be enough to double the endurance time) and
certainly get away with using physically identical but higher capacity
batteries such as say a 7.5 or 8AH battery to replace a 7AH one or use a
5AH one to replace a 4.5AH one. Doubling up seriously increases the risk
of burnout if you suffer frequent and extended outages (meaning 2 or 3
hour outages more than once a year).
--
Regards JB Good
Johny B Good
> On Fri, 23 Sep 2011 08:06:35 -0400, "vaughn"
> <vaugh...@gmail.invalid> wrote:
>
>>
>> "Johny B Good" <inv...@ntlworld.com> wrote in message
>> news:op.v18u4so9kd9x7s@fred...
>> ...>especially as it was supplying a second
>>> level of UPS protection from the protected mains sockets powered by my
>>> SmartUPS 2000 (a 2KVA 1500W unit) that I keep in the basement.
>>
>> This is a good point. I learned the hard way that feeding one UPS from
>> another
>> is a very bad idea. Think of every UPS not only as protection, but as a
>> potential POINT OF FAILURE. To reduce the inevitable failures, simply
>> reduce
>> the number of UPSs. I suffered more than one unnecessary server outage
>> before
>> the lesson sunk in. One layer of UPS "protection" is plenty!
>>
>> Vaughn
>>
> Some UPS units will complain loudly about being fed by another one too
> - some don't like squarewave input.
loading they may present on their mains input, although it's more likely
that the cheap 'stepped' sinewave inverter driving into such a load will
be the first to succumb.
As long as any such cheap UPSes (such as the BackUPS 500 and the Emmerson
Accupower 30) are never used to feed another UPS and only true sine wave
output UPSes (such as the Upsonic UPS600 and the APC SmartUPS 700 and 2000
models), you'll be ok. As you may have gathered, I _was_ quite mindful of
this issue. ;-)
>
> As for the power usage and the "kill-a-watts" units readings - I gort
> a replacement for my EM100, and swings between about 33 and 40 watts
> with the occaisional spike to 70 - I'll run it for a period of time
> and see what the average consumption comes out to. The old unit
> indicated over 60 watts, my guess is less than 35 watts. This is a
> TRUE ONLINE dual conversion UPS, so it will draw significantly more
> than a standby unit.
from a float charged battery, that'll be exactly right!
--
Regards JB Good
cl...@snyder.on.ca
The new EM 100 registers .21 KwH over a period of 5.1 hours - which
translates to almost exactly 40 watts. The line reads 113 volts on the
new unit, and 116 on my old one.My LAB meter reads 115.6 volts - so
the new meter is going back.
It also indicates 0.69 amps, which at 113 volts would be 78 watts.
It is now on the "old" EM 100, which is more accurate voltage-wize,
according to my meter. It registers 0.72 amps at 116 volts - which
would be 83.5 watts. We will see what the KwH reading over time says.
cl...@snyder.on.ca
Johny B Good
I was just confirming that we were both on the same page, as it were. ;-)
>> The new EM 100 registers .21 KwH over a period of 5.1 hours - which
>> translates to almost exactly 40 watts. The line reads 113 volts on the
>> new unit, and 116 on my old one.My LAB meter reads 115.6 volts - so
>> the new meter is going back.
Woah! Hold your horses! Does your LAB meter take a series of samples,
square each value, sum them over a period of time, preferably over at
least one or more complete cycles, average the results then calculate the
square root of that average to accurately measure the RMS voltage?
Or, is it just an accurately calibrated moving coil meter with a
rectifier to produce an average voltage reading which is then calibrated
by the multiplier resistor to produce a deflection on the scale based on
the fixed relationship between average and RMS for a sine waveform?
Or, does the meter simply use the peak value of the mains voltage and use
a multiplier resistor 1.4 times larger than it would be for a constant DC
voltage to scale the peak to its corresponding rms equivalent (again, a
correction factor based on the assumption that the mains is a pure sine
waveform)?
Since that EM100 is already gathering such voltage signed sampling data
to be multiplied by the corresponding current signed sampling data to
calculate both positive and negative power values to be averaged then
summed to produce a net power flow reading, it seems highly likely that
this data and processing power is not going to go to waste.
There's every chance, within the limits of sampling error, that the meter
is giving a more accurate RMS voltage reading than a simple moving coil
meter ever could since the mains waveform (at least in the UK) is quite
noticeably flat topped (if you have you ever looked at the mains waveform
on an oscilloscope, you'll know exactly what I mean).
>>
>> It also indicates 0.69 amps, which at 113 volts would be 78 watts.
No, that just means it's 78VA which may or may not be 78 watts. In this
case, the real power figure is likely to be a lot less though not to the
same extreme you might see with a line interactive switching UPS such as
the SmartUPS 2000 that I've just been testing 3 digital meters and my
analogue Metrawatt power meter on[1].
>>
>> It is now on the "old" EM 100, which is more accurate voltage-wize,
>> according to my meter. It registers 0.72 amps at 116 volts - which
>> would be 83.5 watts. We will see what the KwH reading over time says.
>
>
> Well, they both agree with 40 watts, when the KWH is divided by time.
That does seem the more likely figure in view of the fact that the UPS is
float charging a battery with a steady inverter load on it. Incidently, it
would be useful to know what the UPS's model number is or it's basic
specifications.
[1] I've just spent about an hour in my basement collecting as much
measuring data on the four states of operation of the SmartUPS 2000. These
were rear panel switch in the off position (all functions disabled), rear
panel switch in the on position (charging only enabled, protected power
turned off, then activated from the front panel, enabling protected power
function without load then ditto with a 150W lamp load. I'll only detail a
couple of readings here and now which are relevant to yours (I'll post the
details in a later posting since it is now 4:48 AM BST as I type.
When I was testing the charging only mode (after allowing some 15 minutes
to let the battery return to its fully charged state) the 2000MU-UK (UK
version of the KAW P4400) I was getting a 26.5W and a 136VA reading
(averaged - there was a +/- variation of up to a watt/voltamp either way).
I would have recorded a PF figure but I forgot, however I did record a PF
value of 0.21 on the next stage of the test where I was getting readings
of 29.4W and 136.5VA. Assuming the 40 watt figure is correct that 78VA
figure you calculated implies a PF of just over 50%.
cl...@snyder.on.ca
coil)
>rectifier to produce an average voltage reading which is then calibrated
>by the multiplier resistor to produce a deflection on the scale based on
>the fixed relationship between average and RMS for a sine waveform?
>
> Or, does the meter simply use the peak value of the mains voltage and use
>a multiplier resistor 1.4 times larger than it would be for a constant DC
>voltage to scale the peak to its corresponding rms equivalent (again, a
>correction factor based on the assumption that the mains is a pure sine
>waveform)?
>
> Since that EM100 is already gathering such voltage signed sampling data
>to be multiplied by the corresponding current signed sampling data to
>calculate both positive and negative power values to be averaged then
>summed to produce a net power flow reading, it seems highly likely that
>this data and processing power is not going to go to waste.
Reads a full 3 volts less.
> There's every chance, within the limits of sampling error, that the meter
>is giving a more accurate RMS voltage reading than a simple moving coil
>meter ever could since the mains waveform (at least in the UK) is quite
>noticeably flat topped (if you have you ever looked at the mains waveform
>on an oscilloscope, you'll know exactly what I mean).
>
sine wave as you will find - no "clipping".
>>> It also indicates 0.69 amps, which at 113 volts would be 78 watts.
>
> No, that just means it's 78VA which may or may not be 78 watts. In this
>case, the real power figure is likely to be a lot less though not to the
>same extreme you might see with a line interactive switching UPS such as
>the SmartUPS 2000 that I've just been testing 3 digital meters and my
>analogue Metrawatt power meter on[1].
on-time in hours gives me the 40 watt reading (41.25 watts over 16
hours)- I agree with your 78 VA, rather than 78 watts, because either
the power factor is crasy or the meter is reading peak amps (not
sampling fast enough) and the input current to the UPS is switching at
a frequency that gives a wrong "average" current draw. I'm thinking
power factor, or a combination.
>>>
>>> It is now on the "old" EM 100, which is more accurate voltage-wize,
>>> according to my meter. It registers 0.72 amps at 116 volts - which
>>> would be 83.5 watts. We will see what the KwH reading over time says.
>>
>>
>> Well, they both agree with 40 watts, when the KWH is divided by time.
>
> That does seem the more likely figure in view of the fact that the UPS is
>float charging a battery with a steady inverter load on it. Incidently, it
>would be useful to know what the UPS's model number is or it's basic
>specifications.
>
was a 1000)
The sticker says 4.9 amp at 0.9PF at 120 volts, 50 or 60 hz.
>measuring data on the four states of operation of the SmartUPS 2000. These
>were rear panel switch in the off position (all functions disabled), rear
>panel switch in the on position (charging only enabled, protected power
>turned off, then activated from the front panel, enabling protected power
>function without load then ditto with a 150W lamp load. I'll only detail a
>couple of readings here and now which are relevant to yours (I'll post the
>details in a later posting since it is now 4:48 AM BST as I type.
>
> When I was testing the charging only mode (after allowing some 15 minutes
>to let the battery return to its fully charged state) the 2000MU-UK (UK
>version of the KAW P4400) I was getting a 26.5W and a 136VA reading
>(averaged - there was a +/- variation of up to a watt/voltamp either way).
>I would have recorded a PF figure but I forgot, however I did record a PF
>value of 0.21 on the next stage of the test where I was getting readings
>of 29.4W and 136.5VA. Assuming the 40 watt figure is correct that 78VA
>figure you calculated implies a PF of just over 50%.
>
> HTH & HAND
Right now (on the first UPS) I just turned the output off - leaving
thepower switch on - and I'm getting 0.72 amp, 13-60 watts at 117
volts.
Thw 1000EXT has been sitting, not plugged in, for several months.
It is drawing 84 watts and1.01 amps at 117 volts with the output
turned off, and the same with the output turned off with no load. The
wattage is fluctuating between 82 and 85. We'll see what it says after
the batteries have stabilized.
The first unit is a 36 volt DC battery pack unit, and this one is 42
volt - and has provision to use external battery packs. The tag on
this one says 11.5 amps input and PF of 0.95 -.
Johny B Good
> On Fri, 23 Sep 2011 20:33:56 -0400, cl...@snyder.on.ca wrote:
>
>> On Fri, 23 Sep 2011 23:52:10 +0100, "Johny B Good"
>> <inv...@ntlworld.com> wrote:
>>
>>> On Fri, 23 Sep 2011 20:10:30 +0100, <cl...@snyder.on.ca> wrote:
>>>
>>>> On Fri, 23 Sep 2011 08:06:35 -0400, "vaughn"
>>>> <vaugh...@gmail.invalid> wrote:
>>>>
>>>>>
>>>>> "Johny B Good" <inv...@ntlworld.com> wrote in message
>> The new EM 100 registers .21 KwH over a period of 5.1 hours - which
>> translates to almost exactly 40 watts. The line reads 113 volts on the
>> new unit, and 116 on my old one.My LAB meter reads 115.6 volts - so
>> the new meter is going back.
source of 60Hz mains voltage than that supplied by your electric utility
company. The most obvious source in this case being the output of your UPS.
>>
>> It also indicates 0.69 amps, which at 113 volts would be 78 watts.
be a true fact, the best you can say of your calculated figure of 78 is
that it definitely represents 78VA
>>
>> It is now on the "old" EM 100, which is more accurate voltage-wize,
>> according to my meter. It registers 0.72 amps at 116 volts - which
>> would be 83.5 watts. We will see what the KwH reading over time says.
>
>
> Well, they both agree with 40 watts, when the KWH is devided by time.
small hours of this AM.
--------------------------------------------------------------------------------------
Watt meter test results using a SmartUPS 2000 as a test load
======================================================================================
DEM1379 2000MU-UK N67FU Metrawatt SmartUPS state
--------------------------------------------------------------------------------------
251v 247.5v 251v N/A rear panel switch
0.16A 0.00A 0.80A N/A turned off-
40W 0.0W 0.0W 0.67W * charging disabled
N/A 0.0VA N/A N/A 1 microfarad load
due to EMI filter
--------------------------------------------------------------------------------------
92W 26.5W averaged 28W averaged 30.67W Rear panel switch
0.50A 0.55A 0.505A N/A turned on adding the
N/A 136VA N/A N/A charging cct load
to filter loading
--------------------------------------------------------------------------------------
91W 29.4W averaged 31.5W averaged 33.6W protection enabled
0.51A 0.55A 0.504A N/A and battery given a
N/A 136.5VA avgd N/A N/A 15 minute respite to
N/A 0.21PF N/A N/A recover from startup
test cycle.
--------------------------------------------------------------------------------------
140W avgd 183W avgd 179.5W avgd 184.4W 150W tungsten filament
0.88A 0.89A 0.862A N/A lamp test load plugged
N/A 219VA avgd N/A N/A into UPS outlet
N/A 0.83PF avgd N/A N/A
======================================================================================
250V 246.6V avgd 248V avgd N/A
150W 151W 146.2W avgd 150W meters placed in cct
N/A 152VA N/A N/A between UPS outlet and
0.61A 0.61A 0.589A N/A lamp load to measure
N/A 0.99PF N/A N/A only the UPS load.
--------------------------------------------------------------------------------------
* This 0.67W reading is the power consumed by the N67FU meter
--------------------------------------------------------------------------------------
The above table looks a bit higgledy piggledy to me. It was copied and
pasted from a notepad text file where it all looked rather neater. It
aught to look the same if you copy and paste back into Notepad.
A few comments are in order. The first column shows the figures for a
Globaltronics product sold by Aldi (product code: 6896). I can see quite
clearly that its wattage readings are actually Volt Amperes _NOT_ Watts
(at least in this 'wattage' range). What Globaltronics have done here is
pass off a poor quality (just looking at the 0.16A figure reveals such)VA
meter as a watt meter in the hope that most Aldi customers wouldn't notice
the distinction. The accuracy for purely resistive loads greater than 100W
is good enough for most users, as shown in the final test, (but most users
might not appreciate the distinction between real power and apparent
power).
The next column shows the UK version of the KAW P4400. The poor
wattage/volt ampage/ampage accuracy at sub 10W levels is an indictment of
the choice to squander high accuracy on the voltage sensor rather than
where it matters most, the current sensor. The N67FU is a shining example
of best balance of accuracy between the voltage and current sensor data.
The calculated value of the reactive power due to the 1 microfarad
capacitor in the line input cct (as shown on the cct diagram for this UPS)
for the first row of of readings gives a value of 19.79VA remarkably close
to the 20VA value calculated from the N67FU meter's voltage and current
readings. The cheap Aldi meter's 40W figure (actually a VA figure) arises
simply on account the current sensor data is in error by a factor of two
at this level.
Please note the Metrawatt readings, I have very strong reason to believe
it is giving more accurate wattage readings in the first 3 tests than any
of the digital meters. It is, as might be expected, only when we measure
purely resistive over and above 100W loads that we start to see close
agreement between all four meters.
I could go on, but I'll leave you to draw your own conclusions.
--
Regards JB Good
Martin Riddle
"Jim Wilkins" <murat...@gmail.com> wrote in message
news:j5hubd$quv$1...@dont-email.me...
UPS's measure incoming freq and voltage of a AC line, usually
calculating the RMS of the line voltage.
Most UPS's are quasi sine output, so that screws up the calculations.
Cheers
m II
----------------
"Martin Riddle" wrote in message news:j5l8b2$knh$1...@dont-email.me...
OilLamp
> "danny burstein" <dan...@panix.com> wrote in message
>
> news:j5a1b8$nv3$1...@reader1.panix.com...
>
> > In <j5a0v2$34...@dont-email.me> "Jim Wilkins" <muratla...@gmail.com>
> > writes:
>
> >>> Does the killowatt have a problem reading accurately with UPS units?
>
> >>60W
> >>the
> >>input of a UPS too, but they have always been higher than expected.
>
> > of that "60 watt" lamp when it's plugged directly
> > into the outlet (that is, no UPS inline)?
>
> It's my standard inverter test load. The wattage varies with line voltage of
> course, and probably the age of the bulb as tungsten evaporates off the
> filament. Typically this one reads 55W at 120V. This morning the line is at
> 122.6V and the bulb draws 58W.
>
> I don't have another way to measure AC power that's significantly more
> accurate than a KAW. Except for one old Amprobe my clamp-on current meters
> pretty much agree with it. An in-cal analog oscilloscope with voltage and
> current probe is typically assumed to be accurate to ~3%, and mine are long
> out of calibration.
>
> jsw
Consider stocking up on your standard inverter test load. They may
become scarce in the future.
Johny B Good
wrote:
I know exactly what you mean. About 20 years ago, whilst still employed
by BT, I came across a Strowger PABX that had been decommisioned a few
years before and spotted the 24 225AH cells that had formed the 48v
battery before they'd all been disconnected and left to die.
I selected the best dozen out the bunch (based on appearance alone - the
cell cases were transparent to allow visual inspection of the plates) and
ferried them home (two trips). They'd been left for so long they were all
totally flat and I had to connect each one in turn via a 12v headlamp bulb
(acting as a current limiter/conductivity indicator) to a 12v charger in
order to kickstart each one (the electrolyte was so depleted of H2So4 it
was almost pure water with very low conductivity) before they could be
assembled into a pair of 12v strings that I could then apply the several
charge / discharge cycles needed to revive them. I reckon I had managed to
restore them back to 80% capacity by the time I'd finished the revival
process.
This provided my basement radio shack with a 12v 400AH battery backed
supply for the next 8 or 9 years by which time I'd lost interest in the
hobby and the cells were starting to show signs of old age by their
increased and uneven water consumption.
Realising that all I was doing was burning electricity to electrolyse
water into its constituents, I disconnected them all so I could determine
if I still had enough cells good enough to make up a single bank. The test
was simply to let them stand for a few weeks/months and discard those that
had the most reduced cell voltage from self discharge. The remaining half
dozen "good" cells I left standing with a view to assembling them as a
single battery bank. They're still standing where I left them some ten
years on.
>
>> This is yet another UPS manufacturer who fails to reveal the
>> maintenance
>> consumption figure for its product. ...
>
> The fully charged Tripplite's idle power is about 17W. The batteries
> hold a
> charge well when unplugged for months. I won't know the DC power to
> recharge
> them until I finish the laptop data logger, -after- I fix the hydraulic
> pump
> on my tractor and do some excavating. KAW measurements include the
> charger's
> or lab supply's overhead.
>
> I left it "off" (blinking) and unplugged for a week and measured 0.36 KWH
> ($0.05) to recharge it. I'll probably add a switch to disconnect the
> batteries without removing them, and test points to measure & recharge
> the
> batteries from a lab supply. The batteries and wires are such a tight fit
> that cramming them in bent a connector tab at some point.
I'd be inclined not to attempt that sort of modification, there are too
many issues, not the least of which is finding and fitting a 50 or 60 amp
switch. Allowing the UPS to maintain its own battery pack is usually the
best option and if you want to save electricity because you don't need the
protection for the foreseeable future, the best option is to _still_ let
the UPS keep its battery pack maintained but on a part time basis, say a 4
or 5 hour charging session once every week/fortnight/month, whatever seems
best.
>
>>
>> I'm using an ancient Emerson 30, my very first UPS from about 20 years
>> ago, to protect the Cable modem wireless router powered from a normal
>> mains outlet. The maintenance consumption on this is only around the 7
>> to
>> 8 watt mark. Strange to say, this was the only UPS that ever got used in
>> anger to cover a 3 or 4 hour outage shortly after its acquisition.
>> ....
>
>> Aside from a period of sub one second dropouts a few years back when
>> the
>> local substation contactor gear was in need of an overhaul, we've never
>> had any other outages. Here in the UK, suburban mains supplies are very
>> reliable (most of the UK population lives in the 'burbs) so the desire
>> to
>> protect against a once per generation outage event might seem a little
>> bit
>> over the top but it's my computer kit I'm protecting. The market for
>> UPSes
>> is very tiny indeed in the UK. However, there's every possibility that
>> this may change in the not so distant future.
>
> In New England power suffers from tropical hurricanes, arctic ice storms
> and
> idiotic traffic accidents. I've twice lost it for a week, both in
> midwinter.
Local suburban house voltage distribution, here in the UK, is all served
by underground cables connected to a local sub-station so is largely out
of harm's way. Even the bean counters can't compromise new developments
since we Brits simply wouldn't tolerate such eyesores in the suburban
landscape. Then there's the fact _so_ well and truly proven that the
capital expense of laying a new underground distribution system more than
justifies the savings on the maintenance cost to the extent that it makes
no sense whatsoever to do otherwise except in remote rural areas of the
country.
>
>> Is that using the truck battery to directly power the laptop through its
>> charger socket?
>> Regards JB Good
>
> There isn't much difference between a 12V auto/air adapter which inverts
> to
> 18V or a small 120V inverter plus the mains power supply. I haven't
> measured
> it precisely because the computer's draw isn't steady, and I don't own a
> DC
> current probe for the scope. The only number that matters is run time,
> which
> is too sensitive to hard drive activity and processor + fan speed to
> characterize accurately. There's no point testing it with the computer
> inactive because I wouldn't waste battery power that way during a
> blackout.
>
Yes, the issue is really to do with the number of voltage level
conversions between the utility supply and motherboard voltages. There are
enough such conversion stages without adding yet another two in the form
of a UPS. With laptops, it's rather galling that their battery chargers
are viewed by the money grubbing makers as their version of the Printer
manufacturer's replacement inkjet tank/cartridge profiteering scam.
I'm pretty certain that some (if not all) of the early laptops were
designed to be charged from cigar lighter socket voltage (ranging from
10.8v right up to 15v) since the switching power conversion process used
was quite capable of working over that range, including up to the 16v
limit used by the first mains chargers.
No doubt these chargers were set to the upper limiting voltage rather
than the more useful 12 or 13.8 volts in order to reduce the amount of
current flowing through the plug/socket contacts (an engineering decision)
as well as restricting their utility to solely that of laptop charger
(endorsed by the marketing division).
It only needed one of the competing manufacturers to start a "Voltage
War"(tm) as a means of keeping a monopoly on the supply of replacement
chargers unique to their brand at grossly over-inflated prices by adding
"voltage agnostic[1] spoiler" circuitry to the laptop's power management
module. The requirement for a specific voltage from the charger ( be it
16, 18, 18.5, 19, 19.5, 20, 22 or 24 volts to within +/- half a volt) is
an entirely spurious requirement enforced by that additional circuitry.
The point here is that if the laptop manufacturers had stuck with the
original voltage agnostic power module circuit(anywhere from a 10.8v
minimum to whatever the input capacitor(s) chosen voltage rating was,
typically 16 or 25 volts) you'd have been able to power your laptop
directly from that 12v battery.
[1] agnostic is kind of apt in this case since the manufacturers had "The
Church of 16 volts", "The Latter Day Saints of 22 volts" and so on to
choose from as well as a plethora of connector types and sizes to spice
things up even further.
--
Regards JB Good
Johny B Good
That's not a problem for me. That single 150W lamp I used in my meter
test is one of three that I've taken out of the box of 25 I acquired as a
free gift a couple of decades back. ;-)
--
Regards JB Good
amdx
a garage sale for $5. I got them home and tried one, defective, number
2, defective 3 thru 12 defective. I went back to get my money back and
the guy said "what do you think I'm am, Walmart? I didn't tell him what
I thought he was, but an argument went on until I got my $5 dollars
back. Thought for a time I would have some physical discomfort!
Mikek