under/over charged batteries

[[email protected]]

I sometimes leave a device unused for years. Other times I leave it plugged
in. Is there a poor man's guide to fixing batteries with "memory" (or
whatever) problems?


- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[[email protected]]

Basically put them through some discharge/charge cycles.

Alot of times nothing works, NiCds have a finite life.

 

[mike]

Basically put them through some discharge/charge cycles.

Alot of times nothing works, NiCds have a finite life.

What chemistry?
Cycling a BATTERY may do more harm than good if any of the cells
are shorted, common with disused NiCd's
Cycling the CELLS individually has a higher probability of success.

 

[[email protected]]

On 10/19/2013 6:34 PM, jurb wrote: > Basically put them through some discharge/charge cycles. > > Alot of times nothing works, NiCds have a finite life. > What chemistry? Cycling a BATTERY may do more harm than good if any of the cells are shorted, common with disused NiCd's Cycling the CELLS individually has a higher probability of success.

If any of the cells are shorted that "harm" doesn't matter much does it ? Ithink one of the problems is when the cells become unbalanced. In that case I agree that cycling them individually is much better, but in alot of cases that is impossible or at least impractical.

As far as battery technology has come lately, their limitations are still the main reason we do not have electric cars. Adequate batteries are not cheap for cars. The motors are great, outperforminh gas by quite a margin, partly because they don't need a transmission.

NiCds would be a total waste in cars for example. Capacity versus size makes them unsuitable even for modern cellphones. NiCds simply are outdated, and of a technology that should advance for a bunch of reasons. Some advancesin technology are not desirable, I can think of quite a few, but batteriesneed to improve. Even the latest and greatest have a finite life.

They are also all environmental nightmares. Even if they don't improve capacity much, if they could get them to last longer it would be a definite step in the right direction.

Too bad there are so many problems eith retrofitting newer batteries into older equipment that used to use NiCds. One of the problems of course is industry's refusal to do it because it would not help their profits.

 

[Phil Allison]

Too bad there are so many problems eith retrofitting
newer batteries into older equipment that used to use
NiCds. One of the problems of course is industry's
refusal to do it because it would not help their profits.

** Back in 1996, I bought a Bosch 4.8 volt cordless screwdriver - made in
Switzerland - very basic, just forward and reverse, a handy workshop tool
rather than a tradesman's weapon.

It is now on it's third set of four subC NiCd cells - Sanyo SCR1300s.

Mechanicals are still good, so I expect to fit another set some time in the
future.

Purchase price in 1996 was A$45.

Four SCR1300s cost me A$14.

FYI:

the charger puts out 560mA and has an electronic timer that cuts it off
after 2.5 hours.

Too simple.


..... Phil

 

[mike]

If any of the cells are shorted that "harm" doesn't matter much does it ?

I assume, because of the question mark, that that was a question.
If a cell in your dustbuster is shorted and the charger is stupid, like
the one that comes with a dustbuster,
you can melt the wall-wart...or get it hot enough to open the thermal
fuse in the transformer, if it has one.

In high charge rate devices, you can overheat the cells or the charger
components causing cascading failures.

Many, many consumer devices are designed, and I use that word loosely,
to charge a partially discharged battery. The designers don't seem to
care about fault conditions and domino failures.

I would have taken pictures of the laptop battery that exploded due to a
shorted NiCd, but I managed to get it outside before it exploded
and never found the cell.

So, yes, it can matter quite a lot.

I think one of the problems is when the cells become unbalanced. In that
case I agree that cycling them individually is much better, but in alot
of cases that is impossible or at least impractical.

 

[William Sommerwerck]

"mike" wrote in message

Cycling a BATTERY may do more harm than good if any of the cells
are shorted, common with disused NiCd's
Cycling the CELLS individually has a higher probability of success.

This correct. In a battery, one or more cells might have less capacity than
the others, and will go into reversal before the others have discharged. (I
actually once saw this with an alkaline N cell in a HP calculator!)

 

[William Sommerwerck]

Too bad there are so many problems eith retrofitting newer

batteries into older equipment that used to use NiCds. One
of the problems of course is industry's refusal to do it
because it would not help their profits.

I use NiMH cells in many devices, and they work fine. The Sony products I have
that were designed to recharge nicads have no problem with NiMHs.

The basic rule (at least for power tools) is... Recharge the device at the
first sign the voltage is dropping.

 

[[email protected]]

"I assume, because of the question mark, that that was a question..."

Actually it was rhetorical but good answer. The battery is toast but there is always the issue of the elcheapo charger.

I remember most NiCds charge through a resistor to limit the current, at least the smaller ones like in cordless phones. However I wouldn't put it past them to just let the trsansformer choke on the current to limit it. In that case yup, the charger could fry.

I thought exploding batteries was a more recent phenomenon, but then again there are more things in heav.... wait heaven has absolutely nothing to do with this,...

You know newer cars are like that now. You can't just stick a completely dead battery in them because it will fry the alternator. Cheap junk.

 

[William Sommerwerck]

"Jeff Liebermann" wrote in message

There's no such thing as "memory effect" but there are other problems
with similar symptoms:
<http://en.wikipedia.org/wiki/Memory_effect>

I am generally suspicious of urban legends, but that of "nicad memory" goes
back at least 50 years. I remember reading (in trade magazines) about
rechargeable toothbrushes "losing" their capacity until being run down. I
didn't disbelieve it then, and I don't disbelieve it now.

There's no way to "fix" a dead or dying battery.

You probably don't remember Motorola's (I think) charger for Honeywell
electronic flashes. It used "pulse" charging -- a heavy burst of current,
followed by briefly shorting the battery. Bert Keppler reported in "Modern
Photography" that it did, indeed, "heal" or "fix" older battery packs with
degraded performance.

There is also a wide variety of good (and bad) advice on how to extend

your battery life. See the various articles at:
<http://www.batteryuniversity.com>
<http://gizmodo.com/5952938/everything-you-need-to-know-about-batteries>

I find that the limiting factor to battery life is the charger design,

especially the EOC (end-o-charge) detection. Rather than think about
how one would extend battery life, think about all the ways one could
intentionally destroy a battery with a charger. For example:
1. Charge beyond 100% capacity.
2. Forget to turn off.
3. Re-start the charge cycle when the AC power hiccups.
4. No battery cooling.
5. Quick charge a battery that can't take a quick charge.
6. Overly simplistic charging circuit without stages or EOC
detection.
7. Failure to recognize a dead battery and charge it anyway.
8. EOC detection by battery heating. If the battery gets warm, it's
already overcharged.
9. Failure to recognize that the battery is under load, such as
operating a cell phone while charging.
10. No accommodation for Li-Ion battery inflation when charged.
11. etc.

No argument with any of this.

I've seen all of these in various devices. The problem is that

manufacturers believe consumers are more interested in fast charge
times and long run times, than they are in battery life. So, they set
the charge controller to as close to 100.0% as possible, and charge to
this point as fast as possible. The result is short battery life.
Fortunately, some laptop manufacturers now have a setting in the CMOS
to allow charging to something less than 100.0% in order to extend
battery life.

Two points... Some (if not many) li-ion battery packs have their own chargers.
(The pack for my PDA does.) This increases the probability the battery will be
correctly charged.

When plugged into the charger, my HP notebook won't charge the battery if it's
at 95% capacity or higher. It has to discharge below 95% before the charger
attempts to top it off.

Note that the acceptable range of charge and temperature (green area)
is outside of where literally all users and chargers operate Li-Ion
batteries.

I think you're misreading the graph. The temperature is in Celsius, not
Fahrenheit.

 

[William Sommerwerck]

I have had zero problems with the OEM li-ion batteries that came with anything
I own. The one in my PDA failed gracefully after seven years (almost to the
day), and the third-party replacement is coming up on three years.

Notice I said OEM. The third-party li-ion batteries for my Olympus E-500 and
Yaesu handy-talky failed a few weeks after purchase. The original batteries
are still working, years later.

 

[[email protected]]

*+-the others, and will go into reversal before the others have discharged. (I
*+-actually once saw this with an alkaline N cell in a HP calculator!)

N? Sounds like HP41C



- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[[email protected]]

One is an Acer Aspire One netbook I didn't touch for two years and now the
battery won't charge, but the computer works well with the adapter
plugged in.

Then there was this Siemens SX56 smartphone that I replaced the battery on
and it charged once, then when it discharged, it refused to turn on or
recharge. I had bought it used five years ago and never tried to use it until
recently, so I never knew it ever working. I wish I could find an easily
identifiable short.

A long time ago I had gotten a used Compaq Aero 4/25 and ev'tho I changed the
battery with a new one from Varta three times, it never worked right without
being plugged in.

I wonder if there isn't some poor man's trick by putting a resistor in the
adaptor jack or something.

- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[William Sommerwerck]

...and go into reversal before the others have discharged.

N? Sounds like HP41C.

Could have been, but in this case it was a 28S.

 

[William Sommerwerck]

wrote in message

One is an Acer Aspire One netbook I didn't touch for two years
and now the battery won't charge, but the computer works well
with the adapter plugged in.

When I'm not using my HP, I leave it plugged in. If the battery drops below
95%, the charger will bring it up to 95%, and halt.

 

[mike]

One is an Acer Aspire One netbook I didn't touch for two years and now the
battery won't charge, but the computer works well with the adapter
plugged in.

Then there was this Siemens SX56 smartphone that I replaced the battery on
and it charged once, then when it discharged, it refused to turn on or
recharge. I had bought it used five years ago and never tried to use it until
recently, so I never knew it ever working. I wish I could find an easily
identifiable short.

Depends. Many Lithium chips disconnect permanently when the battery
voltage falls
below some threshold. Others will recover if you open the pack and charge
each cell individually to > 3.5V or so.

A long time ago I had gotten a used Compaq Aero 4/25 and ev'tho I changed the
battery with a new one from Varta three times, it never worked right without
being plugged in

Compaq Aero is my example of a BAD design. There's nothing in between
the power jack and the battery except a FET. The charge current limit is in
the power brick. I made the mistake of charging it from a stiff supply
at the "rated" voltage.
The FET caught fire and burned a hole in the board.

I wonder if there isn't some poor man's trick by putting a resistor in the
adaptor jack or something.

- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[Bob F]

mike wrote:
and domino failures.

I would have taken pictures of the laptop battery that exploded due
to a shorted NiCd, but I managed to get it outside before it exploded
and never found the cell.

That must have been a long time ago. I haven't heard of NiCds in laptops in
years.

 

[[email protected]]

*+-> N? Sounds like HP41C.

*+-Could have been, but in this case it was a 28S.

My mom bought me the first HP41C sold in NYC on New Year's Eve 1979 from
Bloomingdales. It still runs like a song. When I took finance after
engineering school, I programmed a root finder for NPV while my classmates
where struggling with log tables. Since I wrote the program myself, I was
allowed to use it.


- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]