UPS battery saver

[KenK]

I have a UPS with no software. In the past power failures when I was not
home caused the UPS batteries to run dry and damaged them - three 12V 7A
gel cells. Expensive to replace. I try to avoid this situation but
sometimes it is very useful and tempting when I am away for a few hours and
need to do something, like a backup.

Other than a new UPS - expensive! - is there a device I can buy that will
shut off the AC to the UPS after, say, 7 min. or so if I don't shut the
device off and power down currectly myself. I'll have to make one myself
but I'm long out of practice building such stuff.

I suspect not but thought I'd ask. The UPS, if it matters, is an ancient
Emerson UPS 600.

TIA

 

[Paul]

I have a UPS with no software. In the past power failures when I was not
home caused the UPS batteries to run dry and damaged them - three 12V 7A
gel cells. Expensive to replace. I try to avoid this situation but
sometimes it is very useful and tempting when I am away for a few hours and
need to do something, like a backup.

Other than a new UPS - expensive! - is there a device I can buy that will
shut off the AC to the UPS after, say, 7 min. or so if I don't shut the
device off and power down currectly myself. I'll have to make one myself
but I'm long out of practice building such stuff.

I suspect not but thought I'd ask. The UPS, if it matters, is an ancient
Emerson UPS 600.

TIA

Shouldn't the inverter cut off, before the
battery is drained ? That sounds like a functional
failure.

At work, we bought a large number of cheesy UPS boxes.
They would be considered to be on the bottom tier of
the pricing chart. About ten percent of those had
functional failures right out of the box. For example,
one wouldn't flip to battery. Another would not flip back
to AC, when the AC was present. At least none of them
caught fire.

I thought the voltage for cutoff on a 12V battery was 10.5V,
and I can find 1.75V per cell recommended here (for low
discharge rates). The UPS should have been monitoring the
battery, and stopped the inverter below that level (10.5V
as seen at the battery terminals).

http://www.power-sonic.com/images/powersonic/technical/1277751263_20100627-TechManual-Lo.pdf

If you want a UPS that absolutely must have that feature,
some small number of UPS use lithium batteries. Those
cannot be recharged, if the terminal voltage falls below
a certain level (internal shorts form in the cells). To
prevent fires, it's a safety requirement to cut off the
load before the voltage drops too low. So if the thing
uses lithium, instead of the (unnamed in the spec) SLA
Sealed Lead Acid, then you know it's going to cut off.
I would have expected the same thing from a UPS with SLA
in it, that it cut off. But I suppose it would be pennies
cheaper to build, if it just ran the batteries into the
ground. Emerson isn't exactly a small company, and
would know better than to do that.

I wasn't able to find a spec sheet for your
product, and even if there was a spec sheet,
it probably would not say it cuts off at 10.5V.
That's an internal operating detail they don't
have to admit to. They're only interested in user-visible
specs.

You can buy separate modules designed to cut off a battery
before it is discharged too low. But I don't know if that
would be compatible or intended for usage inside a UPS.
That would be more for usage at a camp say, where you
were using a battery to power stuff, and wanted to
prevent deep discharge events from happening.
Might be called a Battery Protector Circuit, rather than
use the word "Cutoff".

http://www.amazon.com/Battery-Prog-Brain-T4-Protector/product-reviews/B00142SAW8

Paul

 

[KenK]

I have a UPS with no software. In the past power failures when I was
not home caused the UPS batteries to run dry and damaged them - three
12V 7A gel cells. Expensive to replace. I try to avoid this situation
but sometimes it is very useful and tempting when I am away for a few
hours and need to do something, like a backup.

Other than a new UPS - expensive! - is there a device I can buy that
will shut off the AC to the UPS after, say, 7 min. or so if I don't
shut the device off and power down currectly myself. I'll have to make
one myself but I'm long out of practice building such stuff.

I suspect not but thought I'd ask. The UPS, if it matters, is an
ancient Emerson UPS 600.

TIA

Sheesh! Should be 'correctly' not 'currectly' and 'AC from the UPS'
rather than 'AC to the UPS'.

 

[BillW50]

Sheesh! Should be 'correctly' not 'currectly' and 'AC from the UPS'
rather than 'AC to the UPS'.

My brain has a built in error checker and I saw what you meant anyway.
Heck I got through half of this paragraph below before I realized
anything was wrong. I must be the worst proofreader. The positive side,
I can read upside down, mirrored, and upside down and mirrored normally
too.

Arocdnicg to rsceearch at Cmabrigde Uinervtisy, it deosn’t mttaer in
waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht
the frist and lsat ltteer are in the rghit pcale. The rset can be a
toatl mses and you can sitll raed it wouthit pobelrm. Tihs is buseace
the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a
wlohe.

 

[VanguardLH]

KenK wrote on 2014/05/31:

I have a UPS with no software. In the past power failures when I was not
home caused the UPS batteries to run dry and damaged them - three 12V 7A
gel cells. Expensive to replace. I try to avoid this situation but
sometimes it is very useful and tempting when I am away for a few hours and
need to do something, like a backup.

Other than a new UPS - expensive! - is there a device I can buy that will
shut off the AC to the UPS after, say, 7 min. or so if I don't shut the
device off and power down currectly myself. I'll have to make one myself
but I'm long out of practice building such stuff.

I suspect not but thought I'd ask. The UPS, if it matters, is an ancient
Emerson UPS 600.

You were not clean which Emerson UPS you have. "600" doesn't identify a
specific family of UPS products. They have a Liebert line for many
kilovolt-amps capacity and meant to be used in a computer room. I
suspect you have the consumer-grade product listed at:

http://www.emersonnetworkpower.com/...ert_PowerSure_PSP_Off-Line_UPS_350-650VA.aspx

According to the quick reference manual, you have to use their Multilink
software if you connect via serial port. That's because they have to
send their commands over that communications protocol. If you connect
the UPS via USB cable then you can use the built-in UPS config options
in Windows. So the easiest is to use a USB cable and use Windows' own
UPS config dialog. After connecting via USB cable, go into Device
Manager (devmgmt.msc) to see if the UPS was detected and listed. Then
go read:

http://www.microsoft.com/resources/...oddocs/en-us/pwrmn_ups_overview.mspx?mfr=true

You get only basic features with the UPS support included in Windows.
For example, it's likely you won't get any logs showing a history of
power brownouts or outages.

Did you connect the UPS to the computer via USB or DB-9 serial (RS-232)
cable? If by serial cable, you have to use their cable. It is likely
to be a specialized cable, not a standard DB-9 cable. One end will be
marked "UPS" and that end must be connected to the UPS and the other end
to the DB-9 port on the computer, not the other way around. For USB,
any standard USB cable will work as long as the connector ends match up
(see http://www.l-com.com/images/usb-tutorial_connectors.gif).

If you demand the UPS is connected via the serial port, good luck
finding the Multilink software required to communicate via RS-232.
Since the software is included with the hardware, you could contact
Emerson to see how to obtain the correct software for that old UPS.

 

[VanguardLH]

VanguardLH wrote on 2014/05/31:

KenK wrote on 2014/05/31:


You were not clean which Emerson UPS you have.

Um, that should've been "clear". That couldn't be a finger fault on a
QWERTY keyboard: "r" and "n" keys are too far apart. Must've been a
brain fart.

After connecting via USB cable, go into Device Manager (devmgmt.msc)
to see if the UPS was detected and listed.

Not likely the Emerson unit will be listed but instead a generic UPS.

 

[Paul]

KenK wrote on 2014/05/31:


You were not clean which Emerson UPS you have. "600" doesn't identify a
specific family of UPS products. They have a Liebert line for many
kilovolt-amps capacity and meant to be used in a computer room. I
suspect you have the consumer-grade product listed at:

http://www.emersonnetworkpower.com/...ert_PowerSure_PSP_Off-Line_UPS_350-650VA.aspx

According to the quick reference manual, you have to use their Multilink
software if you connect via serial port. That's because they have to
send their commands over that communications protocol. If you connect
the UPS via USB cable then you can use the built-in UPS config options
in Windows. So the easiest is to use a USB cable and use Windows' own
UPS config dialog. After connecting via USB cable, go into Device
Manager (devmgmt.msc) to see if the UPS was detected and listed. Then
go read:

http://www.microsoft.com/resources/...oddocs/en-us/pwrmn_ups_overview.mspx?mfr=true

You get only basic features with the UPS support included in Windows.
For example, it's likely you won't get any logs showing a history of
power brownouts or outages.

Did you connect the UPS to the computer via USB or DB-9 serial (RS-232)
cable? If by serial cable, you have to use their cable. It is likely
to be a specialized cable, not a standard DB-9 cable. One end will be
marked "UPS" and that end must be connected to the UPS and the other end
to the DB-9 port on the computer, not the other way around. For USB,
any standard USB cable will work as long as the connector ends match up
(see http://www.l-com.com/images/usb-tutorial_connectors.gif).

If you demand the UPS is connected via the serial port, good luck
finding the Multilink software required to communicate via RS-232.
Since the software is included with the hardware, you could contact
Emerson to see how to obtain the correct software for that old UPS.

On the web page of your first link, there's a spec sheet for the UPS.
You'll need your Word Viewer to read it.

http://www.emersonnetworkpower.com/...s/discontinued product documents/sl-23281.rtf

"Inverter DC Protection

The following DC shutdown levels protect the UPS:

DC Overvoltage Shutdown
DC Undervoltage Shutdown (End of Discharge) <---
DC Undervoltage Warning (Low Battery Reserve)"

The second item there, would be the one that cuts off the
battery drain at 10.5V or so. It doesn't imply a design
intent to "drain to zero".

Paul

 

[VanguardLH]

Paul wrote on 2014/05/31:

On the web page of your first link, there's a spec sheet for the UPS.
You'll need your Word Viewer to read it.

http://www.emersonnetworkpower.com/...s/discontinued product documents/sl-23281.rtf

"Inverter DC Protection

The following DC shutdown levels protect the UPS:

DC Overvoltage Shutdown
DC Undervoltage Shutdown (End of Discharge) <---
DC Undervoltage Warning (Low Battery Reserve)"

The second item there, would be the one that cuts off the
battery drain at 10.5V or so. It doesn't imply a design
intent to "drain to zero".

Paul

Wordpad also shows .rtf file (that's typically the app used in Windows
to create .rtf files since MS Word will normally create .doc files).

Without the cable running from the computer to the UPS, the UPS will
never know the computer wants to shutdown when the power level reaches a
minimum threshold. The UPS won't know anything about how power options
for a UPS are configured in the OS without a signal coming back to the
UPS. So the UPS just stays up until it drains (some have their own
config panels in the UPS to regulate thresholds but I doubt this one has
those features or, if it does, the OP never set the config inside the
UPS).

 

[Paul]

Paul wrote on 2014/05/31:


Wordpad also shows .rtf file (that's typically the app used in Windows
to create .rtf files since MS Word will normally create .doc files).

Without the cable running from the computer to the UPS, the UPS will
never know the computer wants to shutdown when the power level reaches a
minimum threshold. The UPS won't know anything about how power options
for a UPS are configured in the OS without a signal coming back to the
UPS. So the UPS just stays up until it drains (some have their own
config panels in the UPS to regulate thresholds but I doubt this one has
those features or, if it does, the OP never set the config inside the
UPS).

No matter what, that UPS will switch off at 10.5V. It's independent
of anything else. It doesn't matter what protocol is running on that
cable, basic unidirectional warning status indicators, or full protocol,
the inverter will not go below 10.5V.

There are two reasons to stop an inverter running off a 12V battery.

1) Discharging battery below the knee of each cell. The knee is defined
as a point, where most of the available energy has been extracted
from the battery. So little capacity (watt-hours) are left in the battery
below 10.5V, it is pointless to attempt to "milk" them. The inverter
shuts off, to protect the battery. At least some lead acid batteries,
do not tolerate deep discharge well.

2) The inverter shuts off, to protect itself. The inverter effectively
runs at constant power on the output. It is supplying, say, 120V @ 1A
or 120W. On the input, it takes 12V @ 10A to supply the energy (numbers
adjusted for easy math). Now, imagine you let the inverter discharge
the battery source to 6V. The primary current grows to 20A. This is
hard on the primary side components. And if the output of the UPS
was "running at max", now the primary side is running at "double max".
The input switching transistors now have to be made bigger, for this
ridiculous situation. Consequently, to protect the inverter from runaway
input current (caused by the feedback attempting to maintain the output
level), the inverter shuts off to protect itself. On the telecom equipment
we made at work, which connects to a -48V battery room, this is UVLO or
undervoltage lockout. When shopping for converters, we would be looking
for UVLO as a mandatory feature. (Converter type known as point of use
power supplies.)

http://en.wikipedia.org/wiki/Undervoltage-lockout

If a UPS runs a battery flat, in some cases it was because the
battery was actually worn out, and even with no load, just winks out
on its own. But just as likely, something is wrong with the hardware.
In the case of the hundred or so UPS we bought for individual designer
workspaces at work, about ten of those were defective out of the box. And
the defect on each unit was not the same. Each had its own symptoms. For example,
one of the defective ones would stay on battery, even when the AC came back.
A hardware defect in the unit, an inability to trigger on low battery,
is a reason for the thing to trash the battery.

HTH,
Paul

 

[VanguardLH]

KenK wrote on 2014/05/31:

I have a UPS with no software. In the past power failures when I was not
home caused the UPS batteries to run dry and damaged them - three 12V 7A
gel cells. Expensive to replace. I try to avoid this situation but
sometimes it is very useful and tempting when I am away for a few hours and
need to do something, like a backup.

Other than a new UPS - expensive! - is there a device I can buy that will
shut off the AC to the UPS after, say, 7 min. or so if I don't shut the
device off and power down currectly myself. I'll have to make one myself
but I'm long out of practice building such stuff.

I suspect not but thought I'd ask. The UPS, if it matters, is an ancient
Emerson UPS 600.

"in the past" doesn't give a timeline or schedule of when you had to
replace the battery. How old was the battery when replaced?

 

[KenK]

KenK wrote on 2014/05/31:


You were not clean which Emerson UPS you have. "600" doesn't identify
a specific family of UPS products. They have a Liebert line for many
kilovolt-amps capacity and meant to be used in a computer room. I
suspect you have the consumer-grade product listed at:

http://www.emersonnetworkpower.com/en-US/Products/ACPower/DiscontinuedP
roducts/Pages/Liebert_PowerSure_PSP_Off-Line_UPS_350-650VA.aspx

According to the quick reference manual, you have to use their
Multilink software if you connect via serial port. That's because
they have to send their commands over that communications protocol.
If you connect the UPS via USB cable then you can use the built-in UPS
config options in Windows. So the easiest is to use a USB cable and
use Windows' own UPS config dialog. After connecting via USB cable,
go into Device Manager (devmgmt.msc) to see if the UPS was detected
and listed. Then go read:

http://www.microsoft.com/resources/documentation/windows/xp/all/proddoc
s/en-us/pwrmn_ups_overview.mspx?mfr=true

You get only basic features with the UPS support included in Windows.
For example, it's likely you won't get any logs showing a history of
power brownouts or outages.

Did you connect the UPS to the computer via USB or DB-9 serial
(RS-232) cable? If by serial cable, you have to use their cable. It
is likely to be a specialized cable, not a standard DB-9 cable. One
end will be marked "UPS" and that end must be connected to the UPS and
the other end to the DB-9 port on the computer, not the other way
around. For USB, any standard USB cable will work as long as the
connector ends match up (see
http://www.l-com.com/images/usb-tutorial_connectors.gif).

If you demand the UPS is connected via the serial port, good luck
finding the Multilink software required to communicate via RS-232.
Since the software is included with the hardware, you could contact
Emerson to see how to obtain the correct software for that old UPS.

It says 'UPS 600' on the front of the unit and on an ID plate at the
rear. 5A at 120V AC. (5 x 120 = 600)

That's all she wrote.

 

[KenK]

KenK wrote on 2014/05/31:


"in the past" doesn't give a timeline or schedule of when you had to
replace the battery. How old was the battery when replaced?

Sorry. No idea. I didn't notice at the time and it's been a long time
ago. I'd guess a few years old.

 

[VanguardLH]

Although the battery might get a float charge to compensate for self-
discharge and reduce sulfation, the battery will get weaker over time
and eventually die (because so weak as to be worthless). The result is
the UPS won't even switch to battery circuit so there's no power output
from the UPS. This UPS says, according to its online manual, it does a
biweekly self-test; however, the test is so short-lived and it is
unknown if it uses the load of the currently attached gear or some
internal fixed load that it isn't a reliable test. It might test okay
but only use the top charge on a weak battery that cannot handle the
real load.

I've found gel batteries are too weak after sitting 3 years inside a
UPS, about 5 years for lead-acid (non-gel) types. Well, 5 years for the
larger lead-acid batteries. The small motorocyle-sized batteries found
in small UPSes might die sooner. You can use them longer than that but
by then, capacity has already waned so up-time, if any, will be reduced.
To get the same rated up-time from the UPS means doing maintenance to
replace batteries before they get too weak. The UPS may also refuse to
switch to the battery circuit when the battery is too weak. I've not
found reliable the self-test as it seems most use an internal load
instead the actual load by your connected gear and the test is too
short-lived and may only test the draw from the top charge of the
battery. Lifespan varies based on battery type, the surface area of the
plates, temperatures, DoD (depth of discharge), quality of components,
and other factors. Gel batteries are just lead-acid batteries with
silica used to gel up the electrolyte (sulfuric acid). I suppose
they're used in the smaller UPSes for safety in the home along with
users positioning the UPSes on their sides (although gel batteries are
less efficient when on their side than when erect).

I'm not sure why experience shows gel batteries don't last as long as
VRLAB (flooded valve-regulated lead-acid) batteries. Air voids that
adhere to (stick around) to the plates can form in gel batteries during
high amperage flow (charge or recharge), like when the battery is used
for the power source in an outage, which reduces their efficiency and
capacity. The voids (and the silica itself) impede acid flow around the
plates resulting in reduced capacity and accelerate erosion of the
plates. The gel can liquify (acid separates out of silica) during
charging and it can take an hour, or more, to re-gel after recharged.
Recharge voltages for gel batteries are lower than for wet batteries so
recharge time is slower for gels. You need to ensure the correct
battery type is used in the UPS (or any gear that recharges a battery)
as some chargers work for several battery types except gels. The safety
advantages of gel batteries can be a disadvantage to usable lifespan.

Hopefully that UPS really was designed for gel batteries and you didn't
accidentally slide in a gel replacement when a wet battery was in there
before. You said the replacements were gel batteries; however, a sealed
"maintenance-free" battery is not necessarily a gel type of battery.