Evaluating used gel-cell batteries?

[SparkyGuy]

Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?

Thanks,
S.

 

[John Keiser]

I will be interested to read the direct answer to your question.

A slightly different observation is that peeking inside the cells after
removing plastic cover plate and the individual caps [taking precautions for
acid spills] has often revealed very healthy looking plates that have simply
dried out. In that case, I have injected 10 cc's or so of deionized or
distilled water and recharged with an automobile charger. The SLA cells
have then delivered many months of good service in UPS useage.
Little luck reviving the cells when inspection shows significant "bloom"
spanning the plates.


"SparkyGuy" <sparkyguy@mumcrank.ck> wrote in message
news:0001HW.C67A843C006D83EAB0B2D9AF@news.sf.sbcglobal.net...

Gell-cell batteries in UPS's: other than loading with a known load and
timing
how long it takes to drain the battery, is there a simple way to measure
the
health of a gel-cell? Impedance?

Thanks,
S.

 

[Sjouke Burry]

SparkyGuy wrote:

Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?

Thanks,
S.

No. Testing tells all.

 

[Jeff Liebermann]

On Wed, 8 Jul 2009 17:13:32 -0700, SparkyGuy <sparkyguy@mumcrank.ck>
wrote:

Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?

1. Charge the battery with the UPS or whatever. Attach a 12V tail
lamp. Time how long it takes before the bulb goes dim. Compare with
a known good battery. Not every analytical, but good enough.

2. <http://www.westmountainradio.com/CBA_ham.htm>
I have one of these and use it to characterize cell phone LiPo
batteries and some gel cells. The method is the same a before. Charge
the battery as best you can. Use the CBA II to discharge the battery.
However, this time, you get a nifty discharge graph. As before,
compare with a known good battery.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Dave Plowman (News)]

In article <0001HW.C67A843C006D83EAB0B2D9AF@news.sf.sbcglobal.net>,
SparkyGuy <sparkyguy@mumcrank.ck> wrote:

Gell-cell batteries in UPS's: other than loading with a known load and
timing how long it takes to drain the battery, is there a simple way to
measure the health of a gel-cell? Impedance?

A good auto battery seller should have an electronic tester. These give
all the parameters of the battery including actual amp/hour capacity.

--
*I'm not being rude. You're just insignificant

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Charles]

"SparkyGuy" <sparkyguy@mumcrank.ck> wrote in message
news:0001HW.C67A843C006D83EAB0B2D9AF@news.sf.sbcglobal.net...

Gell-cell batteries in UPS's: other than loading with a known load and
timing
how long it takes to drain the battery, is there a simple way to measure
the
health of a gel-cell? Impedance?

Yes, you are already at the door of the solution.

Charge it up and load it significantly and measure the output voltage (which
really sags under heavy load as the battery ages, due to its increased
internal impedance).

In the automotive realm, it was once called "cranking voltage." The
ignition system was disabled so the battery voltage output could be measured
while the starter motor was running. Now, decent garages have test gear
that does a high current load test without all the muss and fuss.

 

[Jeroni Paul]

1.  Charge the battery with the UPS or whatever.  Attach a 12V tail
lamp.  Time how long it takes before the bulb goes dim.  Compare with
a known good battery.  Not every analytical, but good enough.

Very careful not to reverse charge a cell. Do not discarge further
than 10V. If you are watching the voltage when the first cell becomes
completely discharged you can see a quick voltage drop by 2V,
continuing the discharge would ruin the battery.

 

[JB]

"Jeroni Paul" <JERONI.PAUL@terra.es> wrote in message
news:0e92585c-2268-4fd0-99e3-a57e074bdb50@m11g2000yqh.googlegroups.com...

1. Charge the battery with the UPS or whatever. Attach a 12V tail
lamp. Time how long it takes before the bulb goes dim. Compare with
a known good battery. Not every analytical, but good enough.

If you load at 20% of the Amp Hour rating until the voltage falls to 11.9v
you will have a quick test that is meaningful for go-no go test comparison
with a known good battery. Another is to note the ability of the battery to
taper off to 0 amps when charging to 14.4 volts. If the battery keeps
pulling current it will likely self-discharge. This is valid for duali
purpose automotive, RV and marine batteries, but a real deep cycle will act
differently and start boiling with high voltages.and keep drawing current so
beware.

Very careful not to reverse charge a cell. Do not discarge further
than 10V. If you are watching the voltage when the first cell becomes
completely discharged you can see a quick voltage drop by 2V,
continuing the discharge would ruin the battery.

 

[John Robertson]

SparkyGuy wrote:

Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?

Thanks,
S.

How about ESR? Bob Parker's Blue ESR meter will give you some static
clues as to the condition of batteries if compared to known good ones...

http://www.flippers.com/esrkthnt.html (near the bottom of the page)

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Shaun]

"SparkyGuy" <sparkyguy@mumcrank.ck> wrote in message
news:0001HW.C67A843C006D83EAB0B2D9AF@news.sf.sbcglobal.net...

Gell-cell batteries in UPS's: other than loading with a known load and
timing
how long it takes to drain the battery, is there a simple way to measure
the
health of a gel-cell? Impedance?

Thanks,
S.

One easy way to tell if the battery is any good is "how many years has it
been in service ?"

Most gell cell batteries have a maximum life of 5 years, this actually
varies from as low as 3 years to 5 years life. If it's at three year
battery and the UPS is not preforming as it should be, replace the
batteries. Also try to get the same brand of battery that's in there for
replacement. There is alot of third party batteries out there that claim to
be just as good as the big name brands, but there not. I like Panasonic and
CSB brands, they are a little bit more pricey, but worth it.

For discharging, look for the AmpHour rating on the battery. If you put a
load on the battery that draws about that much current, you at "1 C" which
means that the battery should supply that current for 1 hour before it is
discharged. For testing batteries, don't use more that that amount of
current because the AH rating falls off above it, and use the 10 volt rule
that a previous poster wrote is a good guide.

Shaun

 

[Jerry G.]

On Jul 10, 1:46 pm, John Robertson <s...@flippers.com> wrote:

SparkyGuy wrote:
Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?

Thanks,
S.

How about ESR? Bob Parker's Blue ESR meter will give you some static
clues as to the condition of batteries if compared to known good ones...

http://www.flippers.com/esrkthnt.html(near the bottom of the page)

John :-#)#

--
    (Please post followups or tech inquiries to the newsgroup)
  John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
  Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
                     www.flippers.com
       "Old pinballers never die, they just flip out."

If you put an ESR meter accross batteries you will blow the meter!!!
ESR is to be measured with no active voltage!

 

[Jerry G.]

On Jul 8, 8:13 pm, SparkyGuy <sparky...@mumcrank.ck> wrote:

Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?

Thanks,
S.

The best test is to fully charge the battery, and then put a known
resistive load accross it. The ideal load should be 25% of the amp
hour rating of the battery. Time how long it takes for the battery
voltage to drop 10% below its nominal voltage rating. A battery rated
at 12.5 Volt nominal would be considered discharged at 11.36 volts.
Fully charged with no load it should be putting out at least 13.8 to
14.5 Volts.

For example, if a battery is rated at 12.5 Volts / 7.5 Amp hours, the
test load should be rated to pull 1.87 Amps at 12.5 Volts. The
resistance of the load should be 6.7 ohms. The power dissapation would
be about 24 Watts. Therefore the resistor for the load should be rated
at 6.7 ohms at 50 Watts. Always use double the calculated watts for
the resistor rating to prevent the resistor from over heating.

There are commercialy made battery load testers that have high wattage
ratings to fit the required battery test range, and they have
adjustable load resistance. Most of these testers have a load test
that can quickly measure the internal resistance of the battery under
test. (The battery internal resistance test is sort of hard on the
battery).

With the 6.7 ohm / 50 Watt resistor accross the battery, it should
take 4 hours for the battery to reach the 11.36 Volt level. The
recomended maximum charge current for a 7.5 Amp hour battery would
normaly be 1.87 Amps, unless the battery is to be quick charged. This
value is 25% of the rated Amp hours of the battery. For quick charging
the manufacture spec must be considered. Normally to exend the life
span of the battery most manufactures use 50% of the 4C factor. This
is why the battery would take 8 hours to fully charge. After the
battery is charged, the charger will go to the float mode. The float
charge would be 1/10 of the 4C factor which should be 187 ma in this
case. The 4C factor is the 1/4 Amp hour rating of the battery.

For testing purposes, you can use higher resistances. This can also
give you an idea about the battery's condition, not as accurately.
Batteries do not always behave exactly the same at different loads.
Internal thermo factors, and the stability of its internal chemical
reaction are factors to be considered. The older the battery the less
stable its internal stability may be. At greater loads, a battery will
more easily exibit any defects or deficiencies.

As for the gell cells that are used in UPS's, from our experience we
found that they are best to be changed during their third year. We
found that after three years, they no longer give optimum performance.
This is because when inside the UPS unit, there is some heat, and they
battery is constantly charged. At times the UPS batteries are surge
loaded at times. When these UPS's work in the battery mode, they
generaly pull more than the long term recomended amount of power from
the battery. UPS's are emergency devices, and the manufactures try to
make them as economic as possible. Their weak point is usually the
batteries. We have a battery change schedule for our clients which is
every 2.5 years. This way we normally do not see any battery
failures.

Jerry G.

 

[John Robertson]

Jerry G. wrote:

On Jul 10, 1:46 pm, John Robertson <s...@flippers.com> wrote:
SparkyGuy wrote:
Gell-cell batteries in UPS's: other than loading with a known load and timing
how long it takes to drain the battery, is there a simple way to measure the
health of a gel-cell? Impedance?
Thanks,
S.
How about ESR? Bob Parker's Blue ESR meter will give you some static
clues as to the condition of batteries if compared to known good ones...

http://www.flippers.com/esrkthnt.html(near the bottom of the page)

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

If you put an ESR meter accross batteries you will blow the meter!!!
ESR is to be measured with no active voltage!

Not in this case - the Bob Parker ESR design can handle up to around
45VDC (input cap is rated at 50V) safely, but I have an 18V MOV on mine
to help protect against higher charges.

If you had looked at the link you would see the chart shows a few
batteries with typical ESR values. I posted that years ago (a fellow in
AU created it) hoping to get some interest in folks seeing if ESR would
help show if batteries are failing and be able to monitor them as a result.

A simple circuit that would start beeping when the batteries reach a
certain ESR = time to test!

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[notme]

On Wed, 8 Jul 2009 18:50:11 -0700, John Keiser wrote
(in article <adudnWJyzsZI0cjXnZ2dnUVZ_qudnZ2d@powerusenet.com&gt:

I have injected 10 cc's or so of deionized or
distilled water ...

How? I presume you drilled?

 

[none]

notme wrote:

On Wed, 8 Jul 2009 18:50:11 -0700, John Keiser wrote
(in article <adudnWJyzsZI0cjXnZ2dnUVZ_qudnZ2d@powerusenet.com&gt:

I have injected 10 cc's or so of deionized or
distilled water ...

How? I presume you drilled?

I've seen a number of gel-cell batteries with rubber vent caps under a

plastic plate. It's fairly simple to pry them up and squirt a little
water in, but I haven't had any luck with that fixing them.

 

[Charlie+]

On Sat, 25 Jul 2009 22:25:56 -0700, none <""karls\"@(none)"> wrote:

I've seen a number of gel-cell batteries with rubber vent caps under a
plastic plate. It's fairly simple to pry them up and squirt a little
water in, but I haven't had any luck with that fixing them.

I do it when they are brand new - then every two years - then the gellcells
last for a long time. I add 5ml when brand new to each cell, then approx
2ml at subsequent 2yr intervals. This is fine for batteries that dont move
- you would have to be choosy doing it with batteries in very portable
equipment that gets thrown around!
No magic in the figures - that is what it took in my Yuasa batts to JUST
cover the plates/pads with minimal layer of liquid. Quite how they dry out
I dont understand - but they do - I set my float charges at 13.25v rather
than the cram full voltage, the idea was to keep any float gassing off to
the minimum.
Charlie+

 

[none]

Charlie+ wrote:

On Sat, 25 Jul 2009 22:25:56 -0700, none <""karls\"@(none)"> wrote:



I've seen a number of gel-cell batteries with rubber vent caps under a
plastic plate. It's fairly simple to pry them up and squirt a little
water in, but I haven't had any luck with that fixing them.

I do it when they are brand new - then every two years - then the gellcells
last for a long time. I add 5ml when brand new to each cell, then approx
2ml at subsequent 2yr intervals. This is fine for batteries that dont move
- you would have to be choosy doing it with batteries in very portable
equipment that gets thrown around!
No magic in the figures - that is what it took in my Yuasa batts to JUST
cover the plates/pads with minimal layer of liquid. Quite how they dry out
I dont understand - but they do - I set my float charges at 13.25v rather
than the cram full voltage, the idea was to keep any float gassing off to
the minimum.
Charlie+

Thanks for the tip. I'll have to try that. Taking the charge voltage
down from 13.8v to 13.25v sounds worthwhile too. Good thinking.
Since the batteries are made with vents, It was obvious that they were
venting something... You took the reasoning a step farther than I had.

 

[GregS]

In article <bNCdnf5EheKJdfDXnZ2dnUVZ_tqdnZ2d@sysmatrix.net>, none <""karls\"@(none)"> wrote:

Charlie+ wrote:
On Sat, 25 Jul 2009 22:25:56 -0700, none <""karls\"@(none)"> wrote:



I've seen a number of gel-cell batteries with rubber vent caps under a
plastic plate. It's fairly simple to pry them up and squirt a little
water in, but I haven't had any luck with that fixing them.

I do it when they are brand new - then every two years - then the gellcells
last for a long time. I add 5ml when brand new to each cell, then approx
2ml at subsequent 2yr intervals. This is fine for batteries that dont move
- you would have to be choosy doing it with batteries in very portable
equipment that gets thrown around!
No magic in the figures - that is what it took in my Yuasa batts to JUST
cover the plates/pads with minimal layer of liquid. Quite how they dry out
I dont understand - but they do - I set my float charges at 13.25v rather
than the cram full voltage, the idea was to keep any float gassing off to
the minimum.
Charlie+

Thanks for the tip. I'll have to try that. Taking the charge voltage
down from 13.8v to 13.25v sounds worthwhile too. Good thinking.
Since the batteries are made with vents, It was obvious that they were
venting something... You took the reasoning a step farther than I had.

We used to set the trickle charge on some really large eletrolyte
batteries by the amount of bubbling. Constant current is good
in this way, but peiriodic overcharging is also necessary above 14 volts,
along with the normal float of 13.8.

greg

 

[Charlie+]

On Mon, 27 Jul 2009 19:04:02 GMT, zekfrivo@zekfrivolous.com (GregS) wrote
snip

We used to set the trickle charge on some really large eletrolyte
batteries by the amount of bubbling. Constant current is good
in this way, but peiriodic overcharging is also necessary above 14 volts,
along with the normal float of 13.8.

greg

Well that sounds good practical stuff Greg - you couldnt do the bubble test
on a gelcell without a connection and some sort of manometer!
I will try a capacity test on one of my Yuasa 2.8Ah c20 batteries that have
done over 8 years now under my topup when new+2yr+13.25v float regime, just
to see what the longterm effect is on capacity, I would expect a hit but
hopefully it will be a good tradeoff for the longevity problem. My chargers
are constant voltage (otherwise crash charge would not be easy when the
gelcells have been discharged in use) mine are used in burglar alarms where
any discharge is very occasional - if ever - and deep discharge would need a
days long powercut and a series of burglaries at the same time!
Charlie+

 

[Charlie+]

On Tue, 28 Jul 2009 08:38:42 +0100, Charlie+ <charlie@xxx.net> wrote

snip

I will try a capacity test on one of my Yuasa 2.8Ah c20 batteries that have
done over 8 years now under my topup when new+2yr+13.25v float regime, just
to see what the longterm effect is on capacity, I would expect a hit but
hopefully it will be a good tradeoff for the longevity problem. My chargers
are constant voltage (otherwise crash charge would not be easy when the
gelcells have been discharged in use) mine are used in burglar alarms where
any discharge is very occasional - if ever - and deep discharge would need a
days long powercut and a series of burglaries at the same time!
Charlie+

First an apology these batts have now done 7 years 5 months and are Yugel -
the log is inside the equipment and memory got this information slightly
wrong.
Test is now done and I am happy to report a good result:
Discharge conditions 12v 15w bulb with condition of V and A logging every 5
minutes to a final discharge under load level of 10.2v @0.98A. @ 2hours 30
mins. ie not drained - I have no wish to damage the battery.
The averages give a capacity of 2.625Ah, the rated is 2.8 and as the battery
was not crammed (ie left at the 13.25v float level) before the test nor then
emptied at lower discharge rates at the end of the test - I consider this a
very satisfactory result - indeed better than I had expected given the
normally short life of this type of battery.
Charlie+