I work on various alarm systems that use mostly two 12.0 volt 7.0 or 8.0 AH rechargeable lead acid gel cell batteries in series. Although fifteen or so years ago you could get up to ten years out of a typical set of Japanese gel cell batteries, these days it seems that three to five is about all you can expect from the Chinese knock offs that have flooded the market. I used to keep replacements in my van but I found that if they weren't used within a certain time frame they would sulfate. So now I don't keep any of these in stock, instead I buy them as I need them. It's a little more inconvenient but I always get fresh ones this way.

Today I replaced two batteries in a fire alarm panel for a customer. He had bought a case of batteries, he said "a few months ago" and asked me to use his. I used two batteries that he had in stock. The batteries had a 5/13 date code. Although the batteries came right up and worked fine I have to wonder, how well will these two batteries, that have been sitting in a box for over a year perform as compared to two fresh ones? I guess what I'm asking, if anyone knows, how much life span is gone or lost by these batteries just sitting in a box for fourteen months? Thanks, Lenny

wrote:
Although fifteen or so years ago you could get up to ten years out of
a typical set of Japanese gel cell batteries, these days it seems that
three to five is about all you can expect from the Chinese knock offs
that have flooded the market.

I put these same size batteries in computer UPSes; one of them is on its
third set of batteries since I got it in about 2000. I have had pretty
good luck with Panasonic and Power-Sonic brands, and pretty bad luck
with all the others I have tried. All the previous Power-Sonics I have
bought were made in Mexico, but the ones I bought in 2013 were made in
China. I put them in my old UPS but their longevity remains to be seen.

If the utility power is going out more often in your area for some
reason, the alarms will probably go through batteries quicker as well.

I used to keep replacements in my van but I found that if they weren't
used within a certain time frame they would sulfate.

How about connecting them to the van's electrical system when the
ignition is running? That system is *designed* to charge a 12 volt
lead-acid battery. Okay, it's not exactly the right voltage for a
sealed battery, and you probably don't need to charge them every day.
Maybe only hook them up to the van every Monday or every first of the
month or something like that.

I guess what I'm asking, if anyone knows, how much life span is gone
or lost by these batteries just sitting in a box for fourteen months?

Power-Sonic claims that their batteries can be stored for a year before
recharging is required. They also advise charging a new battery after
6 months of storage after *you* get it, to account for the time it sat
in the warehouse.

Paper page 10, PDF page 12 of
http://www.power-sonic.com/images/po...hManual-Lo.pdf
has a chart of self-discharge over time at various temperatures. It
also claims that if the battery is allowed to self-discharge to less
than 60% of its nominal capacity, charging the battery may not restore
full capacity. According to the chart, this 60% point is hit in a
little over 12 months if the battery is stored at 20 C (68 F). At
30 C (86 F) it happens in 8 months, and at 10 C (50 F) it's over 18
months.

The chart doesn't talk about *how much* capacity is permanently lost,
just that it won't be back to 100% capacity.

Matt Roberds

On Wed, 2 Jul 2014 19:12:02 -0700 (PDT),
wrote:

I work on various alarm systems that use mostly two 12.0 volt
7.0 or 8.0 AH rechargeable lead acid gel cell batteries in series.
Although fifteen or so years ago you could get up to ten years
out of a typical set of Japanese gel cell batteries, these days
it seems that three to five is about all you can expect from
the Chinese knock offs that have flooded the market.

I've similar lifetime problems with UPS batteries. I also deal with
weather stations that use the same gel cells. So, besides the
batteries from China what has changed?

1. It's difficult to find a real gel cell today, even if it's labeled
"gel cell". Most everything is AGM (absorbed glass mat). The gel
cell battery has one advantage over the AGM battery. It has a
constant plate top plate spacing, which makes it better for use where
sulfation is possible. AGM has more surface area, and therefore more
capacity per unit volume. They can also be charged at a higher rate
than gel batteries. AGM can handle vibration better.

2. Sophisticated charging circuits allow fast and safe charging very
close to 100% capacity with temperature compensation. In the bad old
daze, a gel cell charger was just a diode and series resistor, that
would charge to about 80% of capacity, and consider that adequate.
Today, the chargers go much closer to 100%. If overcharged, lifetime
is greatly reduced.

3. Sources for batteries have greatly increase. In the bad old daze,
there were perhaps 4 sources of gel cell batteries. The gel batteries
were fairly close to internally identical and very interchangeable.
Today, there are probably about 30 manufacturers with more appearing
every day. Subtle changes are constantly being introduced to give
each manufacturer a competitive advantage, which introduces divergence
in specs and performance. A clue is simply to weigh the battery,
which is a very rough indication of the amount of lead used. In
general, the junk batteries tend to be light weights.

So, what we have today is a far more critical battery system. The
risk of overcharging and going outside the charge profile is high. The
quality of the batteries are all over the map. The interchangeability
of batteries for both AGM vs gel and for different brands is dubious.
Temperature control and compensation is a bad joke.

If you want long life, you'll need to:
1. Don't charge too quickly.
2. Limit the available choice for substitute batteries.
3. Crank DOWN the charge controller to well below 100% capacity.
4. Don't let the battery discharge below about 50%.
5. Put the temp sensor on the battery, not on the controller
6. Don't use gel batteries in vibration prone environments.

Note that most cheap UPS designs break all these recommendations. They
want to recharge as fast as possible so that if the power dies again,
it's ready. They want as long a runtime as possible for advertising
purposes, so they charge as close to 100% as possible. The low voltage
shutdown point is often as low as 25%. Battery temp sensors are never
on the battery.

Or, think about Li-Ion replacement batteries and a "balance" charger:
http://www.batteryspace.com/li-ion-battery-packs-to-replace-lead-acid.aspx


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

"6. Don't use gel batteries in vibration prone environments. "

Hmm, I thought that was the idea behind gel cells partly. That the electrolyte is pretty much trapped against the plates and doesn't shlosh arond. Live nd learn I guess.

What about those battery desulfaters ? From what (actually little) I've seen of them, they put an AC current on them, which presumably somehow dislodges the sulfate from the plates.

Anything to that or is it more of a gimmick ?

Another thing, of which I am less unsure, is/was the practice of junkyards rejuving lead acid (car) batteries by adding epsom salt to the electrolyte. I don't suppose there would be any way to do that here. Also, it didn't seem to last forever.

On Thu, 3 Jul 2014 10:32:48 -0700 (PDT), wrote:

"6. Don't use gel batteries in vibration prone environments. "

Hmm, I thought that was the idea behind gel cells partly.
That the electrolyte is pretty much trapped against the
plates and doesn't shlosh arond. Live nd learn I guess.

Ask any motorcycle shop about which type they prefer. As I understand
it (possibly wrong), the gel type have a wider gap between the plates
because the plate assembly is not very rigid and prone to warping and
bending. AGM is much stiffer, so the plate assembly can be packet
tighter. According one vendor, AGM outsells SLA by 100:1.

I couldn't find much on the difference in construction (I'm in a rush
today) but did find an article that covers the major chemical
differences:
https://www.throttlexbatteries.com/details.aspx?p=A4D3D61DCEB3C859&ppid=59924&beid=4C 71C77B4CB63E74

What about those battery desulfaters ? From what (actually little)
I've seen of them, they put an AC current on them, which presumably
somehow dislodges the sulfate from the plates.
Anything to that or is it more of a gimmick ?

I'm going to pass on trying to answer that question. I don't use them
and have minimal experience with them. The few times I tried a pulse
charger/desulfator, it either didn't do anything useful, or appeared
no better than a conventional charger. However, I'm not sure I was
using it correctly, didn't do much in the way of measurements, and
decided it was easier to replace the battery than to continue testing.

Another thing, of which I am less unsure, is/was the practice of
junkyards rejuving lead acid (car) batteries by adding epsom salt
to the electrolyte. I don't suppose there would be any way to do
that here. Also, it didn't seem to last forever.

SLA means "SEALED lead-acid". Is there something about the word
"sealed" that I'm missing?




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

"SLA means "SEALED lead-acid". Is there something about the word
"sealed" that I'm missing? "

No, I was thinking maybe ddrill a hole, suck some electrolyte out and disolve some in to rejuve it. Sorta like refilling an inkjet cartridge.

Some people used to say if I had any brains I would be dangerous, but hey, maybe I can do without !

Epsom salt, that has magnesium in it right ? That's the metal that burns. Not as good as pure sodium, but burns...

That article you linked to mentions deionized water. Recently my sister bought my Mother a clock that runs on water. You have to change the water from time to time and the manual mentions something about cleaning the electrodes every once in a while.

Maybe this thing has a secondary purpose as a water deionizer ? Other than batteries and certain chemical experiments, what else might they use deionized water for ?

Hmmm.

"Jeff Liebermann" wrote in message
...
On Thu, 3 Jul 2014 10:32:48 -0700 (PDT), wrote:

"6. Don't use gel batteries in vibration prone environments. "

Hmm, I thought that was the idea behind gel cells partly.
That the electrolyte is pretty much trapped against the
plates and doesn't shlosh arond. Live nd learn I guess.

Ask any motorcycle shop about which type they prefer. As I understand
it (possibly wrong), the gel type have a wider gap between the plates
because the plate assembly is not very rigid and prone to warping and
bending. AGM is much stiffer, so the plate assembly can be packet
tighter. According one vendor, AGM outsells SLA by 100:1.

AFAIK - most motorcycle shops are making the transition to AGM batteries -
it was still possible to buy a flooded cell battery last time I wanted one.

wrote in message
...
"6. Don't use gel batteries in vibration prone environments. "

Hmm, I thought that was the idea behind gel cells partly. That the
electrolyte is pretty much trapped against the plates and doesn't shlosh
arond. Live nd learn I guess.

What about those battery desulfaters ? From what (actually little) I've
seen of them, they put an AC current on them, which presumably somehow
dislodges the sulfate from the plates.

The Optimate charger I have includes a desulphate function - it applies 29V
current limited, AFAIK its also pulsed.

wrote in message
...
I work on various alarm systems that use mostly two 12.0 volt 7.0 or 8.0
AH rechargeable lead acid gel cell batteries in series. Although fifteen
or so years ago you could get up to ten years out of a typical set of
Japanese gel cell batteries, these days it seems that three to five is
about all you can expect from the Chinese knock offs that have flooded the
market. I used to keep replacements in my van but I found that if they
weren't used within a certain time frame they would sulfate.

AFAIK, some battery suppliers stock the batteries in a dry charged state -
the gel is supplied in ampules with a seal that is pierced when you press
the ampules into the top of the vent hole.

Last flooded cell motorcycle battery I bought was done like this, the dealer
has a bottle of acid to fill batteries as and when they are sold. It would
be reasonable to assume the same applies to car batteries.

No idea what the shelf life is - but certainly a lot longer than pre filled
ones.

Another thing to consider; lead acid batteries get lazy if they spend their
life on trickle charge and never have to do much work. An occasional heavy
discharge cycle can liven them up a bit if they get sleepy.

On Wednesday, July 2, 2014 10:12:02 PM UTC-4, wrote:
I work on various alarm systems that use mostly two 12.0 volt 7.0 or 8.0 AH rechargeable lead acid gel cell batteries in series. Although fifteen or so years ago you could get up to ten years out of a typical set of Japanese gel cell batteries, these days it seems that three to five is about all you can expect from the Chinese knock offs that have flooded the market. I used to keep replacements in my van but I found that if they weren't used within a certain time frame they would sulfate. So now I don't keep any of these in stock, instead I buy them as I need them. It's a little more inconvenient but I always get fresh ones this way.



Today I replaced two batteries in a fire alarm panel for a customer. He had bought a case of batteries, he said "a few months ago" and asked me to use his. I used two batteries that he had in stock. The batteries had a 5/13 date code. Although the batteries came right up and worked fine I have to wonder, how well will these two batteries, that have been sitting in a box for over a year perform as compared to two fresh ones? I guess what I'm asking, if anyone knows, how much life span is gone or lost by these batteries just sitting in a box for fourteen months? Thanks, Lenny

I used to read a lot of electronics experimenters books when I was a kid, (way back). Some of this reminds me of an experiment I once performed. I took a standard carbon zinc D cell that was dead and soldered two wires, that were connected to a flashlight bulb onto it. I then punched numerous holes in the battery and immersed this contraption into a solution of very salty water. After a few seconds the lamp began to glow.

About fifteen years ago my youngest boy needed an experiment for Science class and I suggested this one, which we named the "Frankenstein battery". It apparently was a big hit at school. Lenny

On Mon, 7 Jul 2014 00:02:34 -0700 (PDT),
wrote:

I used to read a lot of electronics experimenters books when I
was a kid, (way back).

I grew up on a steady diet of Popular Electronics and Carl and Jerry
stories.
http://www.copperwood.com/carlandjerry.htm
Actually, I never really grew up, but we won't go there.

Some of this reminds me of an experiment I once performed. I
took a standard carbon zinc D cell that was dead and soldered
two wires, that were connected to a flashlight bulb onto it.
I then punched numerous holes in the battery and immersed
this contraption into a solution of very salty water. After
a few seconds the lamp began to glow.

About fifteen years ago my youngest boy needed an experiment
for Science class and I suggested this one, which we named
the "Frankenstein battery". It apparently was a big hit at school.
Lenny

Nicely done. I took apart a carbon-zinc alarm battery, and recreated
the battery in a mason jar using vinegar and lemon juice as
electrolytes. That worked, but made a huge mess in the kitchen. My
father moved me to the garage, where I recreated the mess.
Lesson learned: The bigger the mess, the better it works.

Some years later, I was pondering if there was something that could be
done to revive expensive dead NiCd batteries. I knew that
overcharging and overheating NiCd batteries would cause them to
"vent". My guess(tm) was that there was some electrolyte loss
involved. So, I notched a corner of the cell with a triangular file,
and used a syringe to inject some KOH (potassium hydroxide)
electrolyte. That worked in about half the cells I tried, but I was
only able to obtain about half the original ma-hr capacity. Had I had
been able to inject the KOH under pressure, to better distribute it, I
might have done better. Later, I increased the KOH concentration from
about 20% to 100% KOH and created yet another smoking mess.
Lesson learned: A bigger mess does not make a better battery.

Roll forward many years, and I'm still experimenting with NiCd
batteries. This time, I want to see how quickly a NiCd can be
charged. I now had more test equipment and a source of cheap cells. I
would charge the cell from about 10% capacity, to as close to 100% as
possible, as quickly as possible, and then test for capacity using a
West Mtn Radio CBA-II battery analyzer.

NiCd batteries do not get warm until they are overcharged. It is
possible to charge a depleted battery at almost any charge rate
imaginable, as long as it is not overcharged. Overshoot even
slightly, and the battery will overheat and possibly explode. The
threshold is amazingly sharp and varies with battery vendor, age,
condition, past history of battery abuse, and the position of the
moon. In short, it wasn't very predictable. I would successfully
charge a collection of batteries at a 10C rate but eventually find one
battery that would explode without warning or reason. My very fast
charger was not going to be a very safe commercial product.
Lesson learned: A big mess is a good indication that the idea is not
commercially viable.



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

"Lesson learned: The bigger the mess, the better it works."

Yeah, that almost got me disowned, disinherited and thrown into a bag of kittens.

On Wed, 2 Jul 2014 19:12:02 -0700 (PDT),
wrote:

I work on various alarm systems that use mostly two 12.0 volt 7.0 or 8.0 AH rechargeable lead acid gel cell batteries in series. Although fifteen or so years ago you could get up to ten years out of a typical set of Japanese gel cell batteries, these days it seems that three to five is about all you can expect from the Chinese knock offs that have flooded the market. I used to keep replacements in my van but I found that if they weren't used within a certain time frame they would sulfate. So now I don't keep any of these in stock, instead I buy them as I need them. It's a little more inconvenient but I always get fresh ones this way.

Today I replaced two batteries in a fire alarm panel for a customer. He had bought a case of batteries, he said "a few months ago" and asked me to use his. I used two batteries that he had in stock. The batteries had a 5/13 date code. Although the batteries came right up and worked fine I have to wonder, how well will these two batteries, that have been sitting in a box for over a year perform as compared to two fresh ones? I guess what I'm asking, if anyone knows, how much life span is gone or lost by these batteries just sitting in a box for fourteen months? Thanks, Lenny

Lead acid batteries are kind of strange. They share a property with
NiCads in that they can be (re)conditioned. This consists of taking them
up to full charge then running them down to about 75% and bringing then
back to full again. Do this 3 or 4 cycles and it will improve capacity
and longevity. Nicads like being discharged to near 0 better though.

?-)

On Monday, July 7, 2014 10:37:42 PM UTC-4, josephkk wrote:



Lead acid batteries are kind of strange. They share a property with

NiCads in that they can be (re)conditioned. This consists of taking them

up to full charge then running them down to about 75% and bringing then

back to full again. Do this 3 or 4 cycles and it will improve capacity

and longevity.

I'm not sure that's correct. I recently saw a reference that basically says the deeper you discharge a lead acid the less life you get. I'll try and find that again.




Nicads like being discharged to near 0 better though.


?-)

They used to develop a memory. I believe that problem has been solved.

I've just found a couple of stories about people seriously injured by flashlight explosions involving C123s. They were exposed to hydrofluouric acid gas and had long term lung damage. I wouldn't have expected enough chemical in those small batteries but i guess I was wrong.

"Tim R" wrote in message
...
On Monday, July 7, 2014 10:37:42 PM UTC-4, josephkk wrote:



Lead acid batteries are kind of strange. They share a property with

NiCads in that they can be (re)conditioned. This consists of taking them

up to full charge then running them down to about 75% and bringing then

back to full again. Do this 3 or 4 cycles and it will improve capacity

and longevity.

I'm not sure that's correct. I recently saw a reference that basically
says the deeper you discharge a lead acid the less life you get. I'll try
and find that again.

Apparently this especially the case with SLA batteries, I've seen the figure
quoted of 11V that you should cut off the load to prevent permanent loss of
capacity - You can of course buy a leisure battery which is designed for
deep discharge, as long as you don't go too deep too often (and charge it
back up again before sulphation sets in).

AFAIK - Ni-Cd cells like to be fully discharged every once in a while - but
not in a battery of series cells.

All cells are not created equal, and any that run flat first will be reverse
charged by the others - which really does hit capacity!

On Tue, 8 Jul 2014 18:06:29 +0100, "Ian Field"
wrote:

AFAIK - Ni-Cd cells like to be fully discharged every once in a while - but
not in a battery of series cells.

It's not just NiCd batteries, but all batteries. The RC (radio
control) crowd had an ususual opportunity when they started building
their own battery packs and found that charging them in series was a
guaranteed disaster. So, they came up with the "balance" charger
which charges each cell individually. All (and I do mean all) RC
battery packs include seperate connectors for charging and
discharging. I have a fancy balance charger, that will do many things
that ordinary series chargers won't or can't do (if I can decode the
Chinese instructions).

https://www.google.com/#q=balance+charger
https://www.google.com/search?q=balance+charger&tbm=isch

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

"Jeff Liebermann" wrote in message
...

Ni-Cd cells like to be fully discharged every once in a while --
but not in a battery of series cells.

It's not just NiCd batteries, but all batteries.

Not as far as I know. Some lead-acid cells can be permanently damaged if run
down to zero even once. This happened to a Sony Discman battery that was
accidentally discharged slowly, over a period of about a week. It was dead,
dead, dead, and would not take a charge.

On Mon, 07 Jul 2014 19:37:42 -0700, josephkk
wrote:

Lead acid batteries are kind of strange. They share a property with
NiCads in that they can be (re)conditioned. This consists of taking them
up to full charge then running them down to about 75% and bringing then
back to full again. Do this 3 or 4 cycles and it will improve capacity
and longevity. Nicads like being discharged to near 0 better though.

Rubbish. I have to deal with lead-acid batteries of various types
constantly. The only sure way to kill them is to discharge the
battery below some percent of full charge, which varies with battery
chemistry. Run a gel cell battery in a UPS below about 30% of full
charge and you will have a very dead battery in a few weeks.

I'm in a rush, so no authoritative URLs today. Instead, think about
how a lead acid battery works. When you discharge it, some of the
lead goes into solution in the electrolyte. When you recharge it, the
lead gets plated back onto the plates. Pull off too much lead, and
there's not enough surface for the lead in solution to go during
recharge. Eventually, you get a "warped" plate, which is a crude term
for uneven plating.

In my never humble opinion:
1. There's no such thing as NiCd "memory effect", except in very
unique conditions found only in sintered plate batteries (found in
airplane starter batteries).
http://en.wikipedia.org/wiki/Memory_effect
2. Charge cycling (conditioning) *ANY* battery might produce a short
term increase in capacity, but will also accelerate its demise.


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

On 07/08/2014 9:33 AM, Jeff Liebermann wrote:
On Mon, 07 Jul 2014 19:37:42 -0700, josephkk
wrote:

Lead acid batteries are kind of strange. They share a property with
NiCads in that they can be (re)conditioned. This consists of taking them
up to full charge then running them down to about 75% and bringing then
back to full again. Do this 3 or 4 cycles and it will improve capacity
and longevity. Nicads like being discharged to near 0 better though.

Rubbish. I have to deal with lead-acid batteries of various types
constantly. The only sure way to kill them is to discharge the
battery below some percent of full charge, which varies with battery
chemistry. Run a gel cell battery in a UPS below about 30% of full
charge and you will have a very dead battery in a few weeks.

I'm in a rush, so no authoritative URLs today. Instead, think about
how a lead acid battery works. When you discharge it, some of the
lead goes into solution in the electrolyte. When you recharge it, the
lead gets plated back onto the plates. Pull off too much lead, and
there's not enough surface for the lead in solution to go during
recharge. Eventually, you get a "warped" plate, which is a crude term
for uneven plating.

In my never humble opinion:
1. There's no such thing as NiCd "memory effect", except in very
unique conditions found only in sintered plate batteries (found in
airplane starter batteries).
http://en.wikipedia.org/wiki/Memory_effect
2. Charge cycling (conditioning) *ANY* battery might produce a short
term increase in capacity, but will also accelerate its demise.



http://batteryuniversity.com/learn/ good site with answers about
batteries - and they will answer questions too!

John :-#)#

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

"Jeff Liebermann" wrote in message
...

In my never humble opinion:
1. There's no such thing as NiCd "memory effect", except in very
unique conditions found only in sintered plate batteries (found in
airplane starter batteries).
http://en.wikipedia.org/wiki/Memory_effect

I won't dispute the Wikipedia article.

However, I remember when the memory effect (or a memory effect) was discovered
in rechargeable toothbrushes, back in the '60s. Running the cells all the way
down reversed the effect.

"William Sommerwerck" wrote in message
...
"Jeff Liebermann" wrote in message
...

In my never humble opinion:
1. There's no such thing as NiCd "memory effect", except in very
unique conditions found only in sintered plate batteries (found in
airplane starter batteries).
http://en.wikipedia.org/wiki/Memory_effect

I won't dispute the Wikipedia article.

However, I remember when the memory effect (or a memory effect) was
discovered in rechargeable toothbrushes, back in the '60s. Running the
cells all the way down reversed the effect.

The story I first read that was NASA discovered memory effect - apparently
solar charged satellite batteries got charged on a very regular cycle when
the panels could see the sun, and the daily discharge pattern was always the
same - eventually the cells developed only having that much capacity.

Aggessive pulse charging is spectacularly good at curing memory effect in
Ni-Cd cells - my experiments with Ni-Mh were somewhat less impressive.

"Ian Field" wrote in message ...

Aggressive pulse charging is spectacularly good at curing memory effect in
Ni-Cd cells -- my experiments with Ni-Mh were somewhat less impressive.

Motorola introduced a pulse charger for Honeywell Strobonar electronic-flash
packs back in the '60s. "Modern Photography" hailed it as a miracle -- it
could actually bring near-dead packs back to life, and significantly increase
the capacity of "wilted" packs.

Several years later, I asked Bert Keppler why the product had disappeared.
"Uh... the battery packs blew up too often."

On 7/8/2014 3:29 PM, William Sommerwerck wrote:
"Jeff Liebermann" wrote in message
...

In my never humble opinion:
1. There's no such thing as NiCd "memory effect", except in very
unique conditions found only in sintered plate batteries (found in
airplane starter batteries).
http://en.wikipedia.org/wiki/Memory_effect


Some years ago when I worked in the television industry, portable
cameras of the day were powered with Ni-Cad battery packs. I recall
reading a white paper from Anton Bauer about this only somewhat true
memory effect. According to the paper a good battery cell that had an
apparent memory problem would still deliver the total amp hours expected
from the cell but at a reduced voltage of around .1V per cell.

The actual problem stated was manufacturers going the cheap route and
using too few cells for a given voltage...like using 10 cells to get a
nominal 12 volts. In this case that .1V per cell could add up to a full
volt. The solution used in high dollar cameras was to make the battery
packs using 12 cells and then using voltage regulation in the camera to
produce the needed 12V. Then even if a memory effect existed causing the
12 cell battery to lose a nominal 1.2V, there was still enough voltage
to regulate down to the required 12V.

I never made a huge personal study/experiment on this and it could have
just been marketing by the battery company because they always put 12
cells in their 12V batteries but it did make sense to me at the time.

"Jeff Liebermann" wrote in message
...

In my never humble opinion:
1. There's no such thing as NiCd "memory effect", except in very
unique conditions found only in sintered plate batteries (found in
airplane starter batteries).
http://en.wikipedia.org/wiki/Memory_effect

I'm old enough to remember reading about this, circa 1959.

At that time, my father had an appliance store in Towson, MD. He got a number
of industry publications, including "Merchandising Week" (later "Electrical
Merchandising Week"). * These included articles discussing memory effect.

According to these articles, memory effect had reared its ugly head with
rechargeable electric toothbrushes. Users commonly put the handle back on the
charger after every use. So, unless a lot of people used the toothbrush every
day, it went through a shallow discharge/charge cycle. The result was that the
batteries lost their ability to hold a "full" charge.

The solution was discovered when people took their electric toothbrushes on
trips, and the toothbrush's power switch was accidentally turned "on" in the
suitcase, causing a "hard" battery rundown. When the battery was recharged, it
got most of its capacity back.

Now... //This is what the trade publications said.// Whether it is the truth
about "memory effect", I don't know.

* This magazine was my introduction to Charles Rodrigues' cartoons. (I didn't
read "Stereo Review" at the time.)

On 07/03/2014 02:12 AM, wrote:
I work on various alarm systems that use mostly two 12.0 volt 7.0 or 8.0 AH rechargeable lead acid gel cell batteries in series. Although fifteen or so years ago you could get up to ten years out of a typical set of Japanese gel cell batteries, these days it seems that three to five is about all you can expect from the Chinese knock offs that have flooded the market. I used to keep replacements in my van but I found that if they weren't used within a certain time frame they would sulfate. So now I don't keep any of these in stock, instead I buy them as I need them. It's a little more inconvenient but I always get fresh ones this way.

Today I replaced two batteries in a fire alarm panel for a customer. He had bought a case of batteries, he said "a few months ago" and asked me to use his. I used two batteries that he had in stock. The batteries had a 5/13 date code. Although the batteries came right up and worked fine I have to wonder, how well will these two batteries, that have been sitting in a box for over a year perform as compared to two fresh ones? I guess what I'm asking, if anyone knows, how much life span is gone or lost by these batteries just sitting in a box for fourteen months? Thanks, Lenny



You could use them in Renee Everhart's alarm system. Nobody cares if she
gets burnt up in a fire.