I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.

So, how does the UPS's circuitry determines if
the battery is going bad? Is it simply a voltage
measurement, or something more sophisticated?
How difficult would be to modify the UPS to
lower the treshold for a bad battery?

Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

TIA

In sci.electronics.design aurgathor wrote:
I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.
snip
Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

Generally, just fine.
If you put a much bigger battery in, you have to be careful of
overheating due to the extended runtime.

Old car battery from scrapyard is a really cheap way.
Altering thresholds won't do much.

"aurgathor" wrote:

I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.

So, how does the UPS's circuitry determines if
the battery is going bad? Is it simply a voltage
measurement, or something more sophisticated?
How difficult would be to modify the UPS to
lower the treshold for a bad battery?

Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

It will probably work. Beware though with the sealed batteries. An APC
UPS will shut down when the batteries are completely worn out.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

Mainly for safety reasons you should be using the proper battery. The UPS
checks the battery by analysing the current load by pulsing it, and reading
back the decay factor.

If you start messing around by trying batteries that are not properly rated
for it, there will be very little dependability. Also, if you put a battery
with too high an amp hour rating, it will not get charged properly, and the
result may be in damaging the UPS.

As for protecting your investment, it is a bit skimpy for my taste that
someone would not at least put in the proper battery in to their UPS.

--

Jerry G.
=====

"aurgathor" wrote in message
news:1101811497.9+GL3fFjQIKbD+bAQSNOqw@teranews...
I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.

So, how does the UPS's circuitry determines if
the battery is going bad? Is it simply a voltage
measurement, or something more sophisticated?
How difficult would be to modify the UPS to
lower the treshold for a bad battery?

Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

TIA

"Ian Stirling" wrote in message
...
In sci.electronics.design aurgathor wrote:
I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.
snip
Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

Generally, just fine.
If you put a much bigger battery in, you have to be careful of
overheating due to the extended runtime.

Old car battery from scrapyard is a really cheap way.
Altering thresholds won't do much.

Just be sure to put it in a plastic battery box, car batteries, particularly
old ones are notorious for spilling leaking fluid if tilted, jostled or
overcharged. Can make a real mess of carpet and subflooring real quick. A
sealed deap cycle marine gel cell would be ideal.

"Jerry G." wrote in message
...
Mainly for safety reasons you should be using the proper battery. The UPS
checks the battery by analysing the current load by pulsing it, and
reading
back the decay factor.

If you start messing around by trying batteries that are not properly
rated
for it, there will be very little dependability. Also, if you put a
battery
with too high an amp hour rating, it will not get charged properly, and
the
result may be in damaging the UPS.

As for protecting your investment, it is a bit skimpy for my taste that
someone would not at least put in the proper battery in to their UPS.


It should charge just fine, it'll just take longer to fully charge.
Lead-acid batteries aren't particularly sensitive. The proper battery for a
UPS can be pricey, I have an old Trip-Lite that uses an odd size and it
would have been around $100 to replace it, so I installed a pair of somewhat
smaller surplus gel cells and it's been working flawlessly for several
years. I say go for it and experiment, just use common sense with the wiring
so you don't burn the house down.

Hi Jerry,

Mainly for safety reasons you should be using the proper battery. The UPS
checks the battery by analysing the current load by pulsing it, and reading
back the decay factor.

If you start messing around by trying batteries that are not properly rated
for it, there will be very little dependability. Also, if you put a battery
with too high an amp hour rating, it will not get charged properly, and the
result may be in damaging the UPS.

As for protecting your investment, it is a bit skimpy for my taste that
someone would not at least put in the proper battery in to their UPS.



This brings up a whole other question: Are there any low cost UPS that
do use external 12V or 24V batteries? Or where you can add capacity by
external connection? I know there are industrial ones but most are way
out of price range for PC use. This would be nice to ride out longer
outages without stopping work on the PC.

We have an inverter 'mini suitcase' that is used for the fans of a wood
stove in case power goes after we just put a load in the stove. This
inverter with battery isn't a UPS but just a trickle-charged standby
unit. Kept on the shelf just in case, like flashlights, bottled water
and other emergency gear. It does, however, allow the connection of a
large 12V battery for extended runtime.

Regards, Joerg

http://www.analogconsultants.com

I have several modded APC Smart UPS's

Add rear contacts fused and parallel to the internal batteries.
Then you can add any batteries you like as long as the voltage matches the
originals. If you are extending the runtime, very good if you fit a fan to
the grill inside, to cool the ccts inside.
I have a smart APC 1500. It will run at 90% load for 8 hours. No problems at
all.
P.S I use 4 x exteral Chloride 100AH in a seriel parallel combo to give the
needed 24v nominal.

Thanks for all who replied. I looked up the pricing on
replacement batteries and found them kinda high for the
capacity I'd get. Obviously, if I install external batteries,
they'll be installed in a way that even if they leak, they
can't cause much damage (crawl space ;-) . I'll also put
in a fan that will turn ON if it the UPS is running on battery
power, or charging the batteries.

BTW, how do these sealed batteries degrade? Is it sulfating,
or something else? Is there any way to reverse it to some
degree, like charging it with a slightly higher current and/or
voltage, or pulsing it? Again, if the batteries are not 100%
and I only get half of the runtime -- I don't care. But waking
up in the middle of the night because my UPS is beeping
can be highly irritating. :-(


"TheDragon" wrote in message
. ..
I have several modded APC Smart UPS's

Add rear contacts fused and parallel to the internal batteries.
Then you can add any batteries you like as long as the voltage matches the
originals. If you are extending the runtime, very good if you fit a fan to
the grill inside, to cool the ccts inside.
I have a smart APC 1500. It will run at 90% load for 8 hours. No problems
at
all.
P.S I use 4 x exteral Chloride 100AH in a seriel parallel combo to give
the
needed 24v nominal.

Hi!

I have seen some Tripp-Lite NetUPS (?) units that have an external plug for
an external battery.

Theoretically, if you could get the connectors and do a safe job of wiring
them in and mouting them in the case, any UPS could have the ability to
accept an external battery.

I've usually been served well by UPS units that I picked up for free with
dead batteries inside. I just wire a large battery up and fashion a wooden
case or shelf for the entire unit and go from there. I've never had any
problems with doing so, but I would recommend supervising a newly converted
UPS to be sure it will operate correctly. Most recently I got some BIG
sealed gel-cell batteries that were almost new from a big old Tripp-Lite UPS
that blew its top in a big and smoky way. I used them for a backup lighting
system--a small APC UPS is wired to one of the two batteries and then
plugged into two 60 watt lamps. It's enough to get out of a dark basement
when the lights go off at night.

http://greyghost.dyndns.org/ups.jpg - 62.8 KB / 1024x768

William

Hi!

I'll also put
in a fan that will turn ON if it the UPS is running on battery
power, or charging the batteries.

http://greyghost.dyndns.org/ups.jpg (62.8KB / 1024x768)

I need to consider adding that to my modified APC UPS. I have found that it
gets a little warm to the touch over the transistors inside, which don't
seem to have that great of a heatsink anyway. I also have plans for a fuse
holder very close to the battery, just in case. (The UPS itself is
internally fused...)

If you have too much time on your hands, adding an ammeter makes for a nice
touch. I used a small automotive one that shows how much is being pulled off
the battery. It doesn't really have a small enough scale for charging
though.

BTW, how do these sealed batteries degrade? Is it sulfating,
or something else?

I suppose many of them just sulfate, but a lot (maybe even an equal number)
seem to just "boil dry" from the heat at some point. I don't recommend you
do so unless you really know what you're doing and have tools you don't care
about--but I took one such dead battery apart recently. It had basically
turned totally dry inside. There was no liquid to be found anywhere.

If you do that with an old battery, wear eye protection, wash thoroughly
when you're done and safely dispose of the remains. I think it goes without
saying that any open flame or spark is not a good idea.

Those that are run often may just wear out over time. Lead-Acid batteries
aren't really fond of being deeply discharged and then run up again.

Is there any way to reverse it to some
degree, like charging it with a slightly higher current and/or
voltage, or pulsing it?

For sulfated batteries I have heard that a very *slow* charge can at least
get the batteries to limp along for a little while. I have never tried that.

up in the middle of the night because my UPS is beeping
can be highly irritating. :-(

Take the beeper out. With the unit unpowered and the battery removed, just
find the beeper and desolder it or just yank it out. All my UPS units are
now the strong silent type. :-)

William

"William R. Walsh" wrote in
message news:csard.423959$wV.227127@attbi_s54...
Hi!

I have seen some Tripp-Lite NetUPS (?) units that have an external plug
for
an external battery.

Theoretically, if you could get the connectors and do a safe job of wiring
them in and mouting them in the case, any UPS could have the ability to
accept an external battery.

I've usually been served well by UPS units that I picked up for free with
dead batteries inside. I just wire a large battery up and fashion a wooden
case or shelf for the entire unit and go from there. I've never had any
problems with doing so, but I would recommend supervising a newly
converted
UPS to be sure it will operate correctly. Most recently I got some BIG
sealed gel-cell batteries that were almost new from a big old Tripp-Lite
UPS
that blew its top in a big and smoky way. I used them for a backup
lighting
system--a small APC UPS is wired to one of the two batteries and then
plugged into two 60 watt lamps. It's enough to get out of a dark basement
when the lights go off at night.

http://greyghost.dyndns.org/ups.jpg - 62.8 KB / 1024x768

William



If you can run two 60 watt lamps you could light your whole house with
compact fluorescent bulbs, even the ones equivilant to a 100W bulb use only
about 25W.

Hi!

If you can run two 60 watt lamps you could light your whole house with
compact fluorescent bulbs, even the ones equivilant to a 100W bulb use
only
about 25W.

I could run more than that, but I wanted to keep the UPS well within its
operating limits. I think there would be room for four bulbs at 60W, but
that's crowding things a bit and probably very stressful on the circuitry.

As far as the compact flourescent bulbs go, I tried a few that I had in
other fixtures around the house. None of those bulbs reacted very well. Most
of them had some difficulty starting and others failed after running just
fine for a while. I do like these CFL bulbs in certain instances but I don't
think this is one of the places that they work well.

William

aurgathor wrote in message
news:1101811497.9+GL3fFjQIKbD+bAQSNOqw@teranews...
I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.

Yes.

So, how does the UPS's circuitry determines if
the battery is going bad? Is it simply a voltage
measurement, or something more sophisticated?
How difficult would be to modify the UPS to
lower the treshold for a bad battery?

That, of course, depends on the UPS. Some just
watch the potential at the battery REGARDLESS
OF LOAD. Others apply a fixed (known) load and
note how the battery voltage changes. Others
*measure* the load and note the rate of change
of battery voltage. Etc. The Back-UPS 650 Pro isn't
a particularly "high end" unit so I wouldn't expect
much sophistication, there. I'll have to look at the
schematic to see what facilities *are* available to
determine battery state...

Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

Again, it depends on the UPS and the battery chosen.
Let's assume we stick with the same battery *technology*
(i.e. lead acid) so you don't have to address differences in
charging techniques, discharge characteristics, etc.

Typically, the rate a battery is charged is related to the
capacity of the battery. C/10 and C/20 are common
rates. The higher rate obviously leads to greater
*perceived* convenience though usually is tougher
on the battery itself.

One of the risks you run when replacing a battery with
one of a different capacity (physical volume is a rough
parallel to actual capacity -- for a given number of cells)
is that the charger is probably designed with the
*assumption* that a particular battery (capacity) is in place.
Replacing it with a smaller battery could lead to excessive
heating (in the battery) as the battery is now being charged
at a "higher than typical rate". Replacing it with a larger
(capacity) battery could lead to lengthier charge times.

In either case, if the UPS monitors the charge cycle actively,
it can erroneously deduce a battery failure ("Why is this
battery taking so long to charge?" or "Wow! That battery charged
awfully fast! I wonder if that's just a surface charge...")

Using a "car battery" always poses the risk of outgasing which,
if not vented well, can be a fire hazzard. Also, you have to
worry about leaks, spills, etc. as these are not gelled electrolytes.
And, of course, maintenance if the cells are not "mainetenance free".

I had a 3500W unit that ran off 120VDC. I considered using
a set of (10) auto batteries as a cheap way of getting "capacity".
Of course, 10 batteries aren't likely to fit in the living area.
And, with the high charge rate that the UPS used, I was
fearful of putting them in the garage -- 10 batteries potentially
venting into an enclosed space with open sources of ignition
(think gas water heater, automobile, etc.) seemed like an
insurance claim waiting to happen!

So, the only real alternative would be to locate the batteries
outside the garage and run 120VDC through the wall. Then,
run AC from the UPS into the house to support the loads.

But, that means building a shelter to keep the batteries out of the
sun, rain, etc. And, protecting against wildlife chewing on
the wiring, etc. Way too much work!

So, I now use lots of little UPS's. Since outright *outages* here are
rare (a bigger concern are the "2 second wink-outs" you mentioned),
a 500VA - 650VA unit by each critical load is quite adequate.
And, when the machine in question is powered off, there is no
need for the UPS to run at all! (A 3500W UPS wastes a LOT
of power just *idling*!)

The Back-UPS 650 Pro *wants* an 11AHr battery (based on volume).
But, a nice 7AHr will do just fine for you (though you will have to
"pad" it a bit to prevent it from flopping around inside). At most,
that should run you $15 - $18. I think you can even buy the 11AHr
battery for around $20 ("off brand").

What is an outage -- even a 2 second "reboot" -- worth to you?
If it is NOT worth $18, then why are you bothering with a UPS
at all?? (sort of like the folks who spend $50 on a tape backup
system -- that they only use once a month -- and then complain
when they have had a crash and discover last backup they made
is "unreliable")

shrug

--don

"William R. Walsh" wrote in
message news:4adrd.494459$D%.457615@attbi_s51...
Hi!

If you can run two 60 watt lamps you could light your whole house with
compact fluorescent bulbs, even the ones equivilant to a 100W bulb use
only
about 25W.

I could run more than that, but I wanted to keep the UPS well within its
operating limits. I think there would be room for four bulbs at 60W, but
that's crowding things a bit and probably very stressful on the circuitry.

As far as the compact flourescent bulbs go, I tried a few that I had in
other fixtures around the house. None of those bulbs reacted very well.
Most
of them had some difficulty starting and others failed after running just
fine for a while. I do like these CFL bulbs in certain instances but I
don't
think this is one of the places that they work well.

William



That's odd, I run several cheapie Chinese CFL's off a $35 power inverter I
bought at Target a few years ago, haven't seen a problem doing that yet.

"aurgathor" wrote in news:1101846497.
+qTM7IprdMZa0wGRZUm5Zw@teranews:

BTW, how do these sealed batteries degrade? Is it sulfating,
or something else? Is there any way to reverse it to some
degree, like charging it with a slightly higher current and/or
voltage, or pulsing it? Again, if the batteries are not 100%
and I only get half of the runtime -- I don't care. But waking
up in the middle of the night because my UPS is beeping
can be highly irritating. :-(

One of the 12 cells of your batteries was overcharged - and is
destroyed. Unfortunately you can not replace this cell in a sealed lead
acid battery. Other methods of repairing it are not possible.
Batteries in UPS degrade mostly because the cells are not balanced.
All are connected in series, and over time the voltage over the cells
is getting different - because of little mechanical or chemical
differences in each cell.
You can increase the lifetime by lowering the charge voltage. Normally
this is 2.3 volts per cell (or 27.4 for 12). Lowering this to 2.27 will
reduce the available capacity a little, but the lifetime a lot.
But the problem is - how can it be changed in the UPS?

Another way would be a balancing circuit for each cell (ensure that
each cell has no more than 2.3 volts). But with the sealed batteries
you have no access to the connectors of each cell.

Sulfating is another issue, but this takes much longer at room
temperature. I have a torch with a sealed lead acid battery that I
charge once a year. It is still ok! The sulfating is also regularly
removed by the test cycle of the UPS (if there is any) or some drop
outs.

M.
--
Bitte auf antworten.

Thanks for the great replies!! Very enlightening.

I'll take apart the misbahaving UPS and check the
batteries. If there's one that's a lot worse than the
other 3, I'll probably replace it. If it's just a little
worse than the others, I'll try to get a smaller (like
1/3 - 1/2 capacity lead-acid) and parallel with it.
If all are equally bad, I might just need to bite the bullet.

I know that replacing/paralelling one is not a proper
thing, but if Matthias is right, the UPS probably has
1 bad and 3 OK batteries. When I have 3 bad ones,
I'll replace them all. I have another one of the same
UPS, so I might use those extra batteries left
over when all old ones are replaced.

I'll also look into a few other things when the UPS
is open, like slightly decreasing the charging voltage,
or making it more tolerant to marginal batteries.
Assuming I can reverse engineer,or understand the
circuit, which could be very difficult if it uses too much
custom, or VLSI ICs.