Hi,
I have two hardly-used UPS batteries that were stored two years ago after
the UPS was destroyed in a storm. I've now installed them in a UPS (APC
Smart 700) that had its own batteries succumb to leaking. Unfortunately,
they only have about 5V on each battery (supposed to be 14V), and the UPS
immediately powers off instead of coming on and charging them like usual.
I'm presuming this means that it doesn't like the replacement batteries,
and not that the UPS had some other defect associated with the leaked
batteries.

I was thinking of using an automotive 14V trickle charger to attempt to
charge them to the point where the UPS would hopefully accept them back.
Does anyone know if an automotive trickle current is within the normal
range of charging current for a sealed lead acid battery? Is this a
dangerous thing to attempt? I hate to dump another $75 on batteries when
I hardly got any use out of these.

"Ryan Underwood" wrote in message
news
Hi,
I have two hardly-used UPS batteries that were stored two years ago after
the UPS was destroyed in a storm. I've now installed them in a UPS (APC
Smart 700) that had its own batteries succumb to leaking. Unfortunately,
they only have about 5V on each battery (supposed to be 14V), and the UPS
immediately powers off instead of coming on and charging them like usual.
I'm presuming this means that it doesn't like the replacement batteries,
and not that the UPS had some other defect associated with the leaked
batteries.

I was thinking of using an automotive 14V trickle charger to attempt to
charge them to the point where the UPS would hopefully accept them back.
Does anyone know if an automotive trickle current is within the normal
range of charging current for a sealed lead acid battery? Is this a
dangerous thing to attempt? I hate to dump another $75 on batteries when
I hardly got any use out of these.


I'd prefer to see them recharged via via a regulated proper DC power source,
such as a CB 13.8v homebase power unit, rather than a rough DC source like
an automotive charger. Small sealed gel-acid batteries are a little more
delicate than hulking great car batteries. They can be connected directly to
the output of the power source, but I would recommend putting an ammeter
and a 5.6 ohm 10 watt resistor in the line just to monitor what's going on,
and just in case there's any internal shorts on any of the cells. A
voltmeter across the battery terminals wouldn't hurt also. Keeping an eye on
the charge curve, via the meters, will give you a good idea as to the
condition of the batteries.

Arfa

On Wed, 31 Aug 2005 17:05:01 -0500 Ryan Underwood
wrote:

I have two hardly-used UPS batteries that were stored two years ago after
the UPS was destroyed in a storm.

I was thinking of using an automotive 14V trickle charger to attempt to
charge them to the point where the UPS would hopefully accept them back.
Does anyone know if an automotive trickle current is within the normal
range of charging current for a sealed lead acid battery?

I would try the automotive trickle charger. As long as the charge rats
is small (try 1% of the AH rating of the battery) then you should be
okay. When you do this, the battery voltage should come up to 12V
within 1/2 hour. If it does not, then the battery probably has several
shorted cells and can't be fixed.

If the battery comes up to 12V at the 1% charging rate, then just
leave it charging at that rate until the voltage gets up to 14.1V.
This may take a week or 2, depending on how badly sulfated it is.

Once the battery voltage while charging a the 1% rate rises to 14.1V,
you should be able to put the batteries in the UPS and proceed
normally.

Note that none of this insures that these batteries will have a lot of
capacity once charged. You should probably run a "test" power outage,
just to find out whether they are going to be useful.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Ryan Underwood wrote:
Unfortunately, they only have about 5V on each battery (supposed to be
14V),

Actually, something in the region of 12.6 V, no load. If they sat for
two years and only have 5 V no load, the probability is high that they
are junk.

and the UPS immediately powers off instead of coming on and charging
them like usual.

I may be misunderstanding you, but in my experience with a few different
APC UPSes, the UPS doesn't have to be turned on (delivering power to the
outlets) to charge. As soon as you plug the cord into the wall, it
should start charging. Monitor the voltage across the batteries while
you plug the UPS in; it should rise noticeably if the UPS is attempting
to charge them.

I was thinking of using an automotive 14V trickle charger to attempt to
charge them to the point where the UPS would hopefully accept them back.
Does anyone know if an automotive trickle current is within the normal
range of charging current for a sealed lead acid battery?

This depends entirely on the charger. What is its rating, in amps?
What is the amp-hour rating of the batteries? This is usually printed
on the battery. Panasonic even helpfully prints basic charging
information on their sealed lead-acid batteries. You might look for a
data sheet on the batteries you have. If they are no-names, you can
still get an idea: these batteries come in several standard-ish sizes,
so if you can find a battery similar in physical size and electrical
capacity to the one you have, you can use the data sheet for that
battery to get some idea of the charging parameters.

If you have no other information, you want to set it up so that the
battery will take 8 hours or more to fully charge. For example, I have
a 600 VA UPS that uses 2 12 V 7 Ah batteries. Using a 6 amp charger
would probably be too much, because that would recharge the batteries in
a little over an hour. I might chance using a 1 amp charger (7 hours to
charge), but it would be better to use one smaller than that.

I hate to dump another $75 on batteries when I hardly got any use out
of these.

Assuming your 700 VA UPS uses something like the 2 12 V 7 Ah batteries
my 600 VA UPS uses, $75 is way too much. I can replace these batteries
for $15 or so each. As another example, I have a rack-mount UPS that
takes APC's RBC18 "battery cartridge". If I buy it from APC, I pay
about $70. If I buy the individual batteries from Digi-Key or Mouser
and swap the wiring harness over myself, I pay about $25. Now, if you're
using your UPS to support the payroll server at your office, or an oxygen
machine at home, you might be interested in paying the extra $50 to
secure the right to sue APC if the batteries crap out. But for almost
everything else, DIY is the way to go.

Matt Roberds

"Ryan Underwood" wrote in message
news
Hi,
I have two hardly-used UPS batteries that were stored two years ago after
the UPS was destroyed in a storm. I've now installed them in a UPS (APC
Smart 700) that had its own batteries succumb to leaking. Unfortunately,
they only have about 5V on each battery (supposed to be 14V), and the UPS
immediately powers off instead of coming on and charging them like usual.
I'm presuming this means that it doesn't like the replacement batteries,
and not that the UPS had some other defect associated with the leaked
batteries.

I was thinking of using an automotive 14V trickle charger to attempt to
charge them to the point where the UPS would hopefully accept them back.
Does anyone know if an automotive trickle current is within the normal
range of charging current for a sealed lead acid battery? Is this a
dangerous thing to attempt? I hate to dump another $75 on batteries when
I hardly got any use out of these.

Go ahead and try the charger, but they're very likely shot at this point.


In the future, put SLA batteries on a trickle charger while they're stored
rather than waiting for them to go flat and sulfate. I use a 12v wall wart
type transformer with a #47 incandescent lamp in series.

writes:

Ryan Underwood wrote:
Unfortunately, they only have about 5V on each battery (supposed to be
14V),

Actually, something in the region of 12.6 V, no load. If they sat for
two years and only have 5 V no load, the probability is high that they
are junk.

Yup, you're right. Thought they were 14V for some reason. Hard to believe the
longevity is really that bad!

I may be misunderstanding you, but in my experience with a few different
APC UPSes, the UPS doesn't have to be turned on (delivering power to the
outlets) to charge. As soon as you plug the cord into the wall, it
should start charging.

Well, it 'chirps' and the light flickers, but then there is no other sign of
life.

Monitor the voltage across the batteries while you plug the UPS in; it should
rise noticeably if the UPS is attempting to charge them.

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again. Not
sure what's going on here.

If you have no other information, you want to set it up so that the
battery will take 8 hours or more to fully charge. For example, I have
a 600 VA UPS that uses 2 12 V 7 Ah batteries. Using a 6 amp charger
would probably be too much, because that would recharge the batteries in
a little over an hour. I might chance using a 1 amp charger (7 hours to
charge), but it would be better to use one smaller than that.

I see. Thank you for the thoughtful reply.

I hate to dump another $75 on batteries when I hardly got any use out
of these.

Assuming your 700 VA UPS uses something like the 2 12 V 7 Ah batteries
my 600 VA UPS uses, $75 is way too much. I can replace these batteries
for $15 or so each.

I went to batteries.com and saw $40 for the replacement. But it looks like
that is actually both batteries, so it's not as bad as I thought.

Now, if you're using your UPS to support the payroll server at your office, or
an oxygen machine at home, you might be interested in paying the extra $50 to
secure the right to sue APC if the batteries crap out. But for almost
everything else, DIY is the way to go.

Yup. In fact the existing batteries, both the ones that leaked, and the ones
that seem to have failed prematurely, were from different aftermarket battery
retailers on the net. That's what I have been doing is buying batteries and
swapping over the harnesses.

Is it at all possible to buy a long-lasting sealed lead acid battery, or is it
going to be a crapshoot no matter who manufactures it?

On Thu, 01 Sep 2005 00:34:37 -0500 Ryan Underwood
wrote:

writes:

Monitor the voltage across the batteries while you plug the UPS in; it should
rise noticeably if the UPS is attempting to charge them.

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again. Not
sure what's going on here.

That makes me think that the cells are in there backwards.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

On Thu, 01 Sep 2005 04:40:49 GMT "James Sweet"
wrote:

I use a 12v wall wart
type transformer with a #47 incandescent lamp in series.

Yes, a small incandescent bulb makes a very good non-linear limiting
resistor for charging batteries.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Jim Adney writes:

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again. Not
sure what's going on here.

That makes me think that the cells are in there backwards.

The cells are in the packs backwards, or the packs are in the UPS backwards? I
don't see how the packs could be backwards, they are hooked up exactly as the
old ones came out. The +/- leads are too short to reach to the wrong
respective terminals anyway.

Ryan Underwood wrote:
writes:
If they sat for two years and only have 5 V no load, the probability is
high that they are junk.

Hard to believe the longevity is really that bad!

In a UPS that's used constantly in an area that has few power outages (an
average on the order of a few minutes a month or less), the batteries will
last 3 to 5 years or so, and that's about all you will get.

I may be misunderstanding you, but in my experience with a few different
APC UPSes, the UPS doesn't have to be turned on (delivering power to the
outlets) to charge. As soon as you plug the cord into the wall, it
should start charging.

Well, it 'chirps' and the light flickers, but then there is no other sign
of life.

Here is what I have observed of the startup sequence of some different
300-600 VA APC UPSes. This starts with the batteries connected, the UPS
switch off, and the UPS otherwise not connected to anything.

1. Plug UPS cord into wall. UPS may chirp briefly, but will remain off
with no power to battery-backed outlets.

2. UPS will start to charge the batteries. You can see this with a
voltmeter across the batteries or an ammeter in series with the
batteries.

3. Operate the power switch. The UPS will beep and switch on the
battery-backed outlets. After a few seconds, it will do a battery
test. The "on battery" light will come on and you may be able to
hear the transformer humming quietly. If the batteries are good,
this will last for about 10 seconds. If the batteries are bad, it
will last for a second or two, before switching back to line power.
The battery-backed outlets are powered during this entire period.

4. When the battery test is complete, the "on battery" light will go
out and the transformer will stop humming. The UPS should be charging
the batteries again. The battery-backed outlets should still be
powered.

5. Operate the power switch again. The battery-backed outlets will be
shut off, but the batteries should still charge.

Monitor the voltage across the batteries while you plug the UPS in; it
should rise noticeably if the UPS is attempting to charge them.

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again.
Not sure what's going on here.

This _may_ be the self-test failing, then the UPS trying to charge the
battery. It could also be a battery that is so bad that any load
applied by the UPS causes the battery voltage to crater. When the UPS
detects the low voltage, it unloads the battery, which allows the
voltage to rise again.

You might see what each battery does, separate from the UPS, with a load
across it. Something like a 193 (0.5 amp) or 1156 (2 amp) automotive
lamp would be a good load. I suspect that you'll see the same drop in
voltage that you see with the batteries connected to the UPS.

Is it at all possible to buy a long-lasting sealed lead acid battery, or
is it going to be a crapshoot no matter who manufactures it?

In my experience, Panasonic and Power-Sonic make decent SLA (gel-cell)
batteries in the common "small" sizes - 6 V or 12 V, 2 Ah to 15 Ah or
so. Most of the Panasonic gel-cells I have used have been made in
Japan, and most of the Power-Sonic ones have been made in Mexico. I
have never had good luck with any gel cell made in China.

Once you buy a good battery, you have to treat it right. With something
like a UPS, about all you can do is hope that the UPS designer gave you
a good charger, and keep it on charge as much as you can. Batteries
don't like to sit around but they really hate to sit around when
discharged. If you're designing your own charger, READ the technical
notes from the battery vendors first! (Power-Sonic has a fairly good
application note about how to charge their batteries.)

Matt Roberds

wrote in message
news:NZ6Se.17083$Sj1.12520@okepread04...
Ryan Underwood wrote:
writes:
If they sat for two years and only have 5 V no load, the probability is
high that they are junk.

Hard to believe the longevity is really that bad!

In a UPS that's used constantly in an area that has few power outages (an
average on the order of a few minutes a month or less), the batteries will
last 3 to 5 years or so, and that's about all you will get.



I've gotten close to 7 years out of the batteries that are currently in my
UPS, but it's possible to kill a SLA battery in a day or two under the right
conditions, only takes once of discharging it too deeply and it's shot.

On Fri, 02 Sep 2005 10:45:44 -0500 Ryan Underwood
wrote:

Jim Adney writes:

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again. Not
sure what's going on here.

That makes me think that the cells are in there backwards.

The cells are in the packs backwards, or the packs are in the UPS backwards? I
don't see how the packs could be backwards, they are hooked up exactly as the
old ones came out. The +/- leads are too short to reach to the wrong
respective terminals anyway.

The impression I got was that the charger was coming on and driving
current the wrong way thru the batteries, but on second thought, maybe
what you're seeing is just due to some load that the UPS is drawing
from the batteries for a brief moment, until it decides that there's
not enough voltage there for it to work.

I'd take the batteries out of there and just try charging them very
slowly on an ordinary trickle charger. A small 6 or 12V bulb in series
will help limit the current, which is something you really want to do
if you want the best odds of salvaging cells left standing for a long
time.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

In article ,
Ryan Underwood wrote:
Hard to believe the
longevity is really that bad!

Yes, longevity is reduced by storage *without regard for topping up
charges* ...

Interesting. Across one cell, it drops from 5.4V to 2.8V, when initially
plugged in, then after the UPS chirps and dies, it gradually rises again. Not
sure what's going on here.

It's testing the batteries. And then saying "You are kidding!". A lot
of APC units will play dead when confronted with shot batteries. No point
powering up if there's no actual battery backup to rely on
--
--------------------------------------+------------------------------------
Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/