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Terry W. November 5th 06 04:27 PM

Rechargeable Batteries
 
I have recently purchased a new digital camera which uses re-chargeable
batteries. I have not used rechargeables for 10 years and have the
following questions:

The battery pack says charge for 16-20 hours. Will I damage them if they
stay on charge for, say, 3 days or more ?

Is it advisable/necessary to use/discharge the batteries totally before
recharging, or can I recharge them when they are half used. They used to
say that rechargeables developed a "memory" - is that still true?

I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?

Many thanks for your patience with a non-techie type and thanks in
anticipation of your replies.

Terry W.

Graham November 5th 06 04:45 PM

Rechargeable Batteries
 

I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?


I used to make chargers that recharged ordinary batteries when I was
a kid, they wern't all that successful as I remember, but the technique is
called "dirty DC".

Googling that term seems to be useless, as an AC/DC tribute band
uses the same name!

If you are interested, Googling
"dirty DC" "zinc carbon"
will give you the right info.



Dave Fawthrop November 5th 06 05:04 PM

Rechargeable Batteries
 
On Sun, 5 Nov 2006 16:45:05 -0000, "Graham" wrote:

|
| I've seen advertised charges that will recharge ordinary non-rechargeable
| batteries. Are these any good ?
|
|I used to make chargers that recharged ordinary batteries when I was
|a kid, they wern't all that successful as I remember, but the technique is
|called "dirty DC".
|
|Googling that term seems to be useless, as an AC/DC tribute band
|uses the same name!
|
|If you are interested, Googling
| "dirty DC" "zinc carbon"
|will give you the right info.

Google Advanced Search will do a better job.
delete all hits with "Tribute" or "band".
Lots more ways you can limit the search.

--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

Dave Plowman (News) November 5th 06 05:16 PM

Rechargeable Batteries
 
In article ,
Terry W. wrote:
I have recently purchased a new digital camera which uses re-chargeable
batteries. I have not used rechargeables for 10 years and have the
following questions:


The battery pack says charge for 16-20 hours. Will I damage them if
they stay on charge for, say, 3 days or more ?


That depends entirely on the charger - not battery. So you'd need to look
at the instructions for that. If it obviously switches off after charging
it should be ok.

Is it advisable/necessary to use/discharge the batteries totally before
recharging, or can I recharge them when they are half used. They used
to say that rechargeables developed a "memory" - is that still true?


It never was. It was a con to persuade you it was your fault batteries
didn't last.

I've seen advertised charges that will recharge ordinary
non-rechargeable batteries. Are these any good ?


No. And rechargeables cost so little more anyway.

--
*When the going gets tough, use duct tape

Dave Plowman London SW
To e-mail, change noise into sound.

EricP November 5th 06 05:28 PM

Rechargeable Batteries
 
On Sun, 05 Nov 2006 16:27:45 GMT, "Terry W."
wrote:

I have recently purchased a new digital camera which uses re-chargeable
batteries. I have not used rechargeables for 10 years and have the
following questions:

The battery pack says charge for 16-20 hours. Will I damage them if they
stay on charge for, say, 3 days or more ?


Probably, but it depends on the charger and battery type.

Is it advisable/necessary to use/discharge the batteries totally before
recharging, or can I recharge them when they are half used. They used to
say that rechargeables developed a "memory" - is that still true?

What sort of batteries are they?

I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?

Yes but only for a limited number of charges and not 100% capacity.
Normally 10x 15x for good alkaline batteries at 80% capacity.

Many thanks for your patience with a non-techie type and thanks in
anticipation of your replies.

Terry W.


TheOldFellow November 5th 06 05:40 PM

Rechargeable Batteries
 
Is it advisable/necessary to use/discharge the batteries totally before
recharging, or can I recharge them when they are half used. They used
to say that rechargeables developed a "memory" - is that still true?


It never was. It was a con to persuade you it was your fault batteries
didn't last.


What did happen was that a process called 'Dendritic Growth' occurred where
a crystal-like thingy developed inside that shorted out the plates of the
cell. I built a device to destroy them (found recently covered in dust!).

I don't think modern NICADs of NIMH rechargeables do it any more though.

R.

Guy King November 5th 06 05:46 PM

Rechargeable Batteries
 
The message
from "Terry W." contains these words:

I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?


Since you can get 4xAA for £2 from Aldi (and they're OK - I've had loads
and never a dud or low-capacity) why bother?

--
Skipweasel
Pay no attention to that man behind the curtain.

Peter Crosland November 5th 06 05:48 PM

Rechargeable Batteries
 
I have recently purchased a new digital camera which uses
re-chargeable batteries. I have not used rechargeables for 10
years and have the following questions:


The battery pack says charge for 16-20 hours. Will I damage them if
they stay on charge for, say, 3 days or more ?


That depends entirely on the charger - not battery. So you'd need to
look at the instructions for that. If it obviously switches off after
charging it should be ok.


Wrong! It depends on both. You need to use a charger designed for the type
of battery you wish to charge. For example Ni-Cad cells need a quite
differnt charging patter than say Li-Ion ones.

Is it advisable/necessary to use/discharge the batteries totally
before recharging, or can I recharge them when they are half used.
They used to say that rechargeables developed a "memory" - is that
still true?


It never was. It was a con to persuade you it was your fault batteries
didn't last.


Wrong! It was not a con at all, but has been repeatedly proven by
experiment. Ni-Cad cells are particularly prone to this.

I've seen advertised charges that will recharge ordinary
non-rechargeable batteries. Are these any good ?


Wrong again!

They do work but not very well. Not a good choice really unless you are
desparate.

No. And rechargeables cost so little more anyway.


Wrong! Unless of course you regard a price difference of at least 50% as
being insignificant.

Peter Crosland



The Natural Philosopher November 5th 06 06:56 PM

Rechargeable Batteries
 
Terry W. wrote:
I have recently purchased a new digital camera which uses re-chargeable
batteries. I have not used rechargeables for 10 years and have the
following questions:

The battery pack says charge for 16-20 hours. Will I damage them if they
stay on charge for, say, 3 days or more ?

Is it advisable/necessary to use/discharge the batteries totally before
recharging, or can I recharge them when they are half used. They used to
say that rechargeables developed a "memory" - is that still true?

I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?

Many thanks for your patience with a non-techie type and thanks in
anticipation of your replies.

It all depends on the cell chemistry. Lithium batteries will not allow
you to flatten them, and contain charge limiting circuitry anyway. And
can only be charged with chargers designed for them.

Nickel cells can be flattened, but again its not good for them
especially NiMh.

The can be trickled forever..they dump it all as heat anyway.
..

Terry W.


raden November 5th 06 08:10 PM

Rechargeable Batteries
 
In message , "Dave Plowman (News)"
writes
In article ,
Terry W. wrote:
I have recently purchased a new digital camera which uses re-chargeable
batteries. I have not used rechargeables for 10 years and have the
following questions:


The battery pack says charge for 16-20 hours. Will I damage them if
they stay on charge for, say, 3 days or more ?


That depends entirely on the charger - not battery. So you'd need to look
at the instructions for that. If it obviously switches off after charging
it should be ok.

Is it advisable/necessary to use/discharge the batteries totally before
recharging, or can I recharge them when they are half used. They used
to say that rechargeables developed a "memory" - is that still true?


It never was. It was a con to persuade you it was your fault batteries
didn't last.

I had the MOD and their European equivalents fooled then.


--
geoff

Dave Plowman (News) November 6th 06 12:13 AM

Rechargeable Batteries
 
In article ,
Peter Crosland wrote:
The battery pack says charge for 16-20 hours. Will I damage them if
they stay on charge for, say, 3 days or more ?


That depends entirely on the charger - not battery. So you'd need to
look at the instructions for that. If it obviously switches off after
charging it should be ok.


Wrong! It depends on both.


Wrong! It doesn't. ;-)

You need to use a charger designed for the
type of battery you wish to charge. For example Ni-Cad cells need a
quite differnt charging patter than say Li-Ion ones.


And how is this relevant? FWIW, there are battery chargers that cope
automatically with both types and varying number of cells too - and switch
off at the end of the charge cycle.

Is it advisable/necessary to use/discharge the batteries totally
before recharging, or can I recharge them when they are half used.
They used to say that rechargeables developed a "memory" - is that
still true?


It never was. It was a con to persuade you it was your fault batteries
didn't last.


Wrong! It was not a con at all, but has been repeatedly proven by
experiment. Ni-Cad cells are particularly prone to this.


Wrong! It has not been 'proved' at all under normal use.

I've seen advertised charges that will recharge ordinary
non-rechargeable batteries. Are these any good ?


Wrong again!


Have you missed something?

They do work but not very well. Not a good choice really unless you are
desparate.


No. And rechargeables cost so little more anyway.


Wrong! Unless of course you regard a price difference of at least 50% as
being insignificant.


FFS, it is insignificant over the life of the battery. 'Recharging'
alkaline batteries only partially works - and only even that for a few
times. As opposed to hundreds of times for a Ni-Cad or NiMH.

--
*Never kick a cow pat on a hot day *

Dave Plowman London SW
To e-mail, change noise into sound.

Peter Crosland November 6th 06 07:39 AM

Rechargeable Batteries
 
I suggest you go away and do some proper research before spouting
inaccuracies further Dave..

Peter Crosland



The Natural Philosopher November 6th 06 08:48 AM

Rechargeable Batteries
 
Dave Plowman (News) wrote:
In article ,
Peter Crosland wrote:
The battery pack says charge for 16-20 hours. Will I damage them if
they stay on charge for, say, 3 days or more ?
That depends entirely on the charger - not battery. So you'd need to
look at the instructions for that. If it obviously switches off after
charging it should be ok.


Wrong! It depends on both.


Wrong! It doesn't. ;-)


It does.

Dave Plowman (News) November 6th 06 09:57 AM

Rechargeable Batteries
 
In article ,
Peter Crosland wrote:
I suggest you go away and do some proper research before spouting
inaccuracies further Dave..


Peter Crosland


You need to be more specific. I have two chargers that are designed to
handle both Ni-Cad and NiMH - both of which may be left on indefinitely.

But the OP is presumably using the one supplied with the camera so that's
a red herring.

As regards 'memory' with Ni-Cads I stick by my view. It was never a
problem in normal use.

And if you think recharging alkaline batteries worth the effort or cost
you're the one who needs to do some research.

--
*Can fat people go skinny-dipping?

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) November 6th 06 11:04 AM

Rechargeable Batteries
 
In article ,
The Natural Philosopher wrote:
That depends entirely on the charger - not battery. So you'd need to
look at the instructions for that. If it obviously switches off after
charging it should be ok.


Wrong! It depends on both.


Wrong! It doesn't. ;-)


It does.


Lets be clear. Are you denying there are charges that auto sense between
Ni-Cad and NiMH and shut off after use?

--
*If you lived in your car, you'd be home by now *

Dave Plowman London SW
To e-mail, change noise into sound.

Peter Crosland November 6th 06 11:31 AM

Rechargeable Batteries
 
I suggest you go away and do some proper research before spouting
inaccuracies further Dave..


Peter Crosland


You need to be more specific. I have two chargers that are designed to
handle both Ni-Cad and NiMH - both of which may be left on
indefinitely.

But the OP is presumably using the one supplied with the camera so
that's a red herring.

As regards 'memory' with Ni-Cads I stick by my view. It was never a
problem in normal use.


The problem with, and always has been, with Ni-Cad cells is that they do
develope memory unless you discharge them fully and then recharge them. The
problem with them is that people seldom do this and indeed often leave them
on charge day after day.

And if you think recharging alkaline batteries worth the effort or
cost you're the one who needs to do some research.


Please point to the post where I said about alkaline cells.

--
Peter Crosland



Guy King November 6th 06 12:30 PM

Rechargeable Batteries
 
The message
from "Dave Plowman (News)" contains these words:

You need to be more specific. I have two chargers that are designed to
handle both Ni-Cad and NiMH - both of which may be left on indefinitely.


My fast=charger's like that. Shove anything in it and a while later it's
charged but leaving cells in for a week doesn't seem to have any adverse
effects. They're hot at the end of the fast-charge cycle but cool right
down to (as far as I can tell) ambient once it switches to trickle.

--
Skipweasel
Pay no attention to that man behind the curtain.

[email protected] November 6th 06 12:59 PM

Rechargeable Batteries
 
Peter Crosland wrote:

As regards 'memory' with Ni-Cads I stick by my view. It was never a
problem in normal use.


The problem with, and always has been, with Ni-Cad cells is that they do
develope memory unless you discharge them fully and then recharge them. The
problem with them is that people seldom do this and indeed often leave them
on charge day after day.


If you read up on the "memory effect" you will find that it is very
rare indeed. It only occurs when a NiCad is repeatedly charged and
discharged in *exactly* the same way (i.e. both times and levels). It
was discovered in NiCads used on satellites where the cycling was very
regular indeed.

Thus "memory effect" is very, very unikely indeed to be seen in any
domestic use of NiCad cells.

The only sensible reasons that I can think of for discharging before
recharging a-

To guarantee they are fully discharged before applying a full
charge which would otherwise overcharge them. A good
"intelligent" charger shouldn't need this.

To try and "even up" cells used in series so that all cells will
start completely discharged when charging them. However charging
cells in series is best avoided if you can. Discharging cells in
series completely is a *very* bad idea because the weakest cells
will get reverse charged towards the end of the discharge and
this does them no good at all.


--
Chris Green

[email protected] November 6th 06 01:24 PM

Rechargeable Batteries
 


On Nov 5, 5:48 pm, "Peter Crosland" wrote:
I have recently purchased a new digital camera which uses
re-chargeable batteries. I have not used rechargeables for 10
years and have the following questions:


The battery pack says charge for 16-20 hours. Will I damage them if
they stay on charge for, say, 3 days or more ?


That depends entirely on the charger - not battery. So you'd need to
look at the instructions for that. If it obviously switches off after
charging it should be ok.


Wrong! It depends on both. You need to use a charger designed for the type
of battery you wish to charge. For example Ni-Cad cells need a quite
differnt charging patter than say Li-Ion ones.


Well, obviously! We assume the OP has been provided with the charger
appropriate to his cells, in which case all that matters is whether the
charger is designed not to overcharge them.


Is it advisable/necessary to use/discharge the batteries totally
before recharging, or can I recharge them when they are half used.
They used to say that rechargeables developed a "memory" - is that
still true?


It never was. It was a con to persuade you it was your fault batteries
didn't last.


Wrong!

It was not a con at all, but has been repeatedly proven by
experiment. Ni-Cad cells are particularly prone to this.


Only under very particular circumstances such as spacecraft passing
regularly between night and day where the batteries were regularly
charged/discharged between the same points. It doesn't happen in normal
domestic use. Just google "nasa nicad memory effect".


I've seen advertised charges that will recharge ordinary
non-rechargeable batteries. Are these any good ?


Wrong again!

They do work but not very well. Not a good choice really unless you are
desparate.

No. And rechargeables cost so little more anyway.


Wrong! Unless of course you regard a price difference of at least 50% as
being insignificant.


You have to look at the lifecycle of the cells. Even 100% difference
would be insignificant when you take into account the number and
effectiveness of recharge cycles possible with true rechargeables.

MBQ


Guy King November 6th 06 04:13 PM

Rechargeable Batteries
 
The message
from contains these words:

If you read up on the "memory effect" you will find that it is very
rare indeed. It only occurs when a NiCad is repeatedly charged and
discharged in *exactly* the same way (i.e. both times and levels). It
was discovered in NiCads used on satellites where the cycling was very
regular indeed.


Can happen with model aircraft - run at full pelt until the onboard
electronics cut the power at a given voltage and then are recharged
using expensive controlled chargers. Exactly the situation you describe.

--
Skipweasel
Pay no attention to that man behind the curtain.

Dave Plowman (News) November 6th 06 04:52 PM

Rechargeable Batteries
 
In article ,
Peter Crosland wrote:
As regards 'memory' with Ni-Cads I stick by my view. It was never a
problem in normal use.


The problem with, and always has been, with Ni-Cad cells is that they do
develope memory unless you discharge them fully and then recharge them.


Not so - they have to be discharged to precisely the same point time and
time again - very unlikely in most uses.

The problem with them is that people seldom do this and indeed often
leave them on charge day after day.


That is an entirely different matter. Many early chargers were crude in
the extreme and would soon damage a battery by overcharging. But that's
got nothing to do with memory effect. Makers of these cheap crude chargers
might well imply it was, though.

And if you think recharging alkaline batteries worth the effort or
cost you're the one who needs to do some research.


Please point to the post where I said about alkaline cells.


You mentioned recharging non rechargeable batteries. I'd guess few use
zinc carbon types these days. But these can't be recharged satisfactorily
ether.

--
*Lottery: A tax on people who are bad at math.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) November 6th 06 06:21 PM

Rechargeable Batteries
 
In article ,
Guy King wrote:
If you read up on the "memory effect" you will find that it is very
rare indeed. It only occurs when a NiCad is repeatedly charged and
discharged in *exactly* the same way (i.e. both times and levels). It
was discovered in NiCads used on satellites where the cycling was very
regular indeed.


Can happen with model aircraft - run at full pelt until the onboard
electronics cut the power at a given voltage and then are recharged
using expensive controlled chargers. Exactly the situation you describe.


But a Ni-Cad gives an extremely stable output until near flat so the
situation you describe is OK. What does harm them is to run them *totally*
flat as many feel inclined to do.

--
*Income tax service - We‘ve got what it takes to take what you've got.

Dave Plowman London SW
To e-mail, change noise into sound.

Chris Hodges November 6th 06 08:40 PM

Rechargeable Batteries
 
Dave Fawthrop wrote:
On Sun, 5 Nov 2006 16:45:05 -0000, "Graham" wrote:

|
| I've seen advertised charges that will recharge ordinary non-rechargeable
| batteries. Are these any good ?
|
|I used to make chargers that recharged ordinary batteries when I was
|a kid, they wern't all that successful as I remember, but the technique is
|called "dirty DC".
|
|Googling that term seems to be useless, as an AC/DC tribute band
|uses the same name!
|
|If you are interested, Googling
| "dirty DC" "zinc carbon"
|will give you the right info.

Google Advanced Search will do a better job.
delete all hits with "Tribute" or "band".
Lots more ways you can limit the search.

Or use "-band" "-tribute" etc in the standard search.

--
Spamtrap in use
To email replace 127.0.0.1 with btinternet dot com

Chris Hodges November 6th 06 10:10 PM

Rechargeable Batteries
 
Peter Crosland wrote:
snip
The problem with, and always has been, with Ni-Cad cells is that they do
develope memory unless you discharge them fully and then recharge them. The
problem with them is that people seldom do this and indeed often leave them
on charge day after day.

snip
LiIons on laptops which are normally plugged in often suffer - my Compaq
now has about 20 minutes life from a nominal 2 hour battery. Toshibas
don't seem so bad though. This isn't technically memory effect, but it
might as well be to most users.

Chris

--
Spamtrap in use
To email replace 127.0.0.1 with btinternet dot com

Chris Hodges November 6th 06 10:17 PM

Rechargeable Batteries
 
Guy King wrote:
The message
from "Terry W." contains these words:


I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?



Since you can get 4xAA for £2 from Aldi (and they're OK - I've had loads
and never a dud or low-capacity) why bother?

I don't put stupidly cheap batteries in expensive kit in case they leak.
You can often get panansonics cheap and I've never had one leak on
me, Ikea's are Varta and again I've never had one leak. The "powercell"
pack I got aren't worth putting in anything but a cheap torch.

When the GPS or our previous digital camera had finished with a set of
alkalines there was a good month or so of life left for my cordless
mouse and they're pretty bright in a torch, so it's worth hanging on to
them.

btw some digital compacts, while they will work on NiMH/NiCad aren't as
good - slower recycle time especially (but not just) when using flash,
hardly any use per charge etc. Hopefully this shouldn't be as bad if
the camera has its own rechargeable and a charger though.

Chris

--
Spamtrap in use
To email replace 127.0.0.1 with btinternet dot com

Guy King November 6th 06 10:43 PM

Rechargeable Batteries
 
The message
from Chris Hodges contains these words:

Since you can get 4xAA for £2 from Aldi (and they're OK - I've had loads
and never a dud or low-capacity) why bother?

I don't put stupidly cheap batteries in expensive kit in case they leak.


I've got a dozen of them and despite abuse by the kids none have leaked
in the year or two I've had 'em.

--
Skipweasel
Pay no attention to that man behind the curtain.

Dave Plowman (News) November 7th 06 12:14 AM

Rechargeable Batteries
 
In article ,
Chris Hodges wrote:
LiIons on laptops which are normally plugged in often suffer - my Compaq
now has about 20 minutes life from a nominal 2 hour battery. Toshibas
don't seem so bad though. This isn't technically memory effect, but it
might as well be to most users.


I'm not overly impressed with the life of LiIon under some conditions,
although this may be down to the charger. They have their uses where the
small size/high capacity is vital, but don't like deep discharge as a
regular thing.

--
*Can atheists get insurance for acts of God? *

Dave Plowman London SW
To e-mail, change noise into sound.

The Natural Philosopher November 7th 06 08:00 AM

Rechargeable Batteries
 
Dave Plowman (News) wrote:
In article ,
Chris Hodges wrote:
LiIons on laptops which are normally plugged in often suffer - my Compaq
now has about 20 minutes life from a nominal 2 hour battery. Toshibas
don't seem so bad though. This isn't technically memory effect, but it
might as well be to most users.


I'm not overly impressed with the life of LiIon under some conditions,
although this may be down to the charger. They have their uses where the
small size/high capacity is vital, but don't like deep discharge as a
regular thing.

Yes. Or rather, no they certainly don't.

Failing capacity is a sure sign of interior damage.

I have to say that they seem to be getting better though.

[email protected] November 7th 06 09:30 AM

Rechargeable Batteries
 

Dave Plowman (News) wrote:
In article ,
Chris Hodges wrote:
LiIons on laptops which are normally plugged in often suffer - my Compaq
now has about 20 minutes life from a nominal 2 hour battery. Toshibas
don't seem so bad though. This isn't technically memory effect, but it
might as well be to most users.


I'm not overly impressed with the life of LiIon under some conditions,
although this may be down to the charger. They have their uses where the
small size/high capacity is vital, but don't like deep discharge as a
regular thing.


In my (limited) experience, the key words in the PP's post are
"normally plugged in". I know someone who always used their laptop on
mains power. When they came to use it on battery after about a year,
it was next to useless. The Lithium polymer battery in my mobile phone
seems to be going quite well after 3 years plus, and it's only ever on
charge when it needs to be.

Probably best to exercise batteries as they were intended to be used.
Attempts to extend their life by leaving them on permanent charge seem
to be counter productive.

--
"How much can I get away with and still go to heaven."


The Natural Philosopher November 7th 06 10:00 AM

Rechargeable Batteries
 
wrote:
Dave Plowman (News) wrote:
In article ,
Chris Hodges wrote:
LiIons on laptops which are normally plugged in often suffer - my Compaq
now has about 20 minutes life from a nominal 2 hour battery. Toshibas
don't seem so bad though. This isn't technically memory effect, but it
might as well be to most users.

I'm not overly impressed with the life of LiIon under some conditions,
although this may be down to the charger. They have their uses where the
small size/high capacity is vital, but don't like deep discharge as a
regular thing.


In my (limited) experience, the key words in the PP's post are
"normally plugged in". I know someone who always used their laptop on
mains power. When they came to use it on battery after about a year,
it was next to useless. The Lithium polymer battery in my mobile phone
seems to be going quite well after 3 years plus, and it's only ever on
charge when it needs to be.

Probably best to exercise batteries as they were intended to be used.
Attempts to extend their life by leaving them on permanent charge seem
to be counter productive.

Again, I think its down to the age, and quality of the cells and the
charge regulation circuitry.

Lithium cell actually are best stored at half charge, but they vary
markedly in terms of self discharge, internal resistance and peak power
delivery.

The good news is that its an area of rapid devlopment.

[email protected] November 7th 06 10:59 AM

Rechargeable Batteries
 
Chris Hodges wrote:
Peter Crosland wrote:
snip
The problem with, and always has been, with Ni-Cad cells is that they do
develope memory unless you discharge them fully and then recharge them. The
problem with them is that people seldom do this and indeed often leave them
on charge day after day.

snip
LiIons on laptops which are normally plugged in often suffer - my Compaq
now has about 20 minutes life from a nominal 2 hour battery. Toshibas
don't seem so bad though. This isn't technically memory effect, but it
might as well be to most users.

But won't be helped by a full discharge. It's just basic "worn out
battery" effect.

--
Chris Green

John Laird November 7th 06 11:56 AM

Rechargeable Batteries
 
The Natural Philosopher wrote:
wrote:

In my (limited) experience, the key words in the PP's post are
"normally plugged in". I know someone who always used their laptop on
mains power. When they came to use it on battery after about a year,
it was next to useless. The Lithium polymer battery in my mobile phone
seems to be going quite well after 3 years plus, and it's only ever on
charge when it needs to be.

Probably best to exercise batteries as they were intended to be used.
Attempts to extend their life by leaving them on permanent charge seem
to be counter productive.

Again, I think its down to the age, and quality of the cells and the
charge regulation circuitry.


Well, that covers all bases ! Not that I would disagree.

Lithium cell actually are best stored at half charge, but they vary
markedly in terms of self discharge, internal resistance and peak power
delivery.

The good news is that its an area of rapid devlopment.


Indeed - apparently Toshiba have some super new technology that permits
1-minute recharge times, although I suspect it may never arrive in the
initially announced form.

--
"VD is nothing to clap about."


The Natural Philosopher November 7th 06 12:15 PM

Rechargeable Batteries
 
John Laird wrote:
The Natural Philosopher wrote:
wrote:
In my (limited) experience, the key words in the PP's post are
"normally plugged in". I know someone who always used their laptop on
mains power. When they came to use it on battery after about a year,
it was next to useless. The Lithium polymer battery in my mobile phone
seems to be going quite well after 3 years plus, and it's only ever on
charge when it needs to be.

Probably best to exercise batteries as they were intended to be used.
Attempts to extend their life by leaving them on permanent charge seem
to be counter productive.

Again, I think its down to the age, and quality of the cells and the
charge regulation circuitry.


Well, that covers all bases ! Not that I would disagree.

Lithium cell actually are best stored at half charge, but they vary
markedly in terms of self discharge, internal resistance and peak power
delivery.

The good news is that its an area of rapid devlopment.


Indeed - apparently Toshiba have some super new technology that permits
1-minute recharge times, although I suspect it may never arrive in the
initially announced form.


yeah..I wouldn't say that that particular cell is either more than
vapourware, or actually any use apart from possible automotive
applications. BEVs need to get down to about 3-5 minute recharge times -
of at least 70-80% capacity anyway - without sever loss of efficiency
and damage.

But of the 7 or 8 lithium packs I have that fly my model planes, the
very worst one on power delivery.. it gets hot and loses power if used a
high power (20A on a 2000mAh pack) continuously..is the very best on
charge retention.

Some of the high discharge ones are a lot worse..and don't seem to be
lasting well either.

So it would seem that there are many micro adjustments to cell
construction and chemistry that can optimise in different directions,
but not ALL directions.

But anyway they are streets ahead of nickel cells in every respect
except the ability to go flat and survive, the recharge times and the
cost.


Guy King November 7th 06 09:49 PM

Rechargeable Batteries
 
The message
from Chris Hodges contains these words:

Since you can get 4xAA for £2 from Aldi (and they're OK - I've had loads
and never a dud or low-capacity) why bother?


I don't put stupidly cheap batteries in expensive kit in case they leak.



I've got a dozen of them and despite abuse by the kids none have leaked
in the year or two I've had 'em.

I've had some leak in the packaging and some leak in a torch - 2
different pound shop packs.


Are we still talking NiMHs here, or primary cells? I'd not use cheapie
primary cells for anything.

--
Skipweasel
Pay no attention to that man behind the curtain.

Chris Hodges November 7th 06 10:11 PM

Rechargeable Batteries
 
Guy King wrote:
The message
from Chris Hodges contains these words:


Since you can get 4xAA for £2 from Aldi (and they're OK - I've had loads
and never a dud or low-capacity) why bother?


I don't put stupidly cheap batteries in expensive kit in case they leak.



I've got a dozen of them and despite abuse by the kids none have leaked
in the year or two I've had 'em.

I've had some leak in the packaging and some leak in a torch - 2
different pound shop packs.

Chris

--
Spamtrap in use
To email replace 127.0.0.1 with btinternet dot com

Dave Fawthrop November 8th 06 04:29 AM

Rechargeable Batteries
 
On Tue, 7 Nov 2006 21:49:35 GMT, Guy King wrote:

|The message
|from Chris Hodges contains these words:
|
| Since you can get 4xAA for ?2 from Aldi (and they're OK - I've had loads
| and never a dud or low-capacity) why bother?
|
|
| I don't put stupidly cheap batteries in expensive kit in case they leak.
|
|
| I've got a dozen of them and despite abuse by the kids none have leaked
| in the year or two I've had 'em.
|
| I've had some leak in the packaging and some leak in a torch - 2
| different pound shop packs.
|
|Are we still talking NiMHs here, or primary cells? I'd not use cheapie
|primary cells for anything.

I use cheapie Lidl Alkaline cells for low current uses where I expect them
to last for months or even years. Smoke detectors, IR TV hoofadoofas and
the like, also cheapie Lidl torches which I leave around and expect them to
work when picked up after years sitting unused. NiMHs self discharge
much faster and need recharging regularly. NiMhs are fine for regularly
used torches cameras, GPSs and other high current uses.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

Peter Parry November 8th 06 07:11 PM

Rechargeable Batteries
 
On Mon, 6 Nov 2006 11:31:08 -0000, "Peter Crosland"
wrote:


The problem with, and always has been, with Ni-Cad cells is that they do
develope memory unless you discharge them fully and then recharge them.


They don't, and in domestic batteries never have. What they do
develop is voltage depression which is caused not by failing to
discharge them fully, that is irrelevant, but simply by consistently
overcharging them.
--
Peter Parry.
http://www.wpp.ltd.uk/

Dave Fawthrop November 8th 06 10:00 PM

Rechargeable Batteries
 
On Wed, 08 Nov 2006 22:10:28 +0000, Chris Hodges
wrote:

|Dave Fawthrop wrote:
| NiMhs are fine for regularly
| used torches cameras, GPSs and other high current uses.
|Funny you should say that, my Garmin doesn't like even freshly charged
|NiMHs - you get ~3 hours life compared to a quoted 22 from alkalines. 1
|walk instead of quite a few.

I never believe quoted figures, only what I find on test.

I get two thirds of knack all from alkalines, a full days walk from NiMH
with another pair as backup. All I need :-)
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

Chris Hodges November 8th 06 10:08 PM

Rechargeable Batteries
 
Guy King wrote:
The message
from Chris Hodges contains these words:


Since you can get 4xAA for £2 from Aldi (and they're OK - I've had loads
and never a dud or low-capacity) why bother?


I don't put stupidly cheap batteries in expensive kit in case they leak.


I've got a dozen of them and despite abuse by the kids none have leaked
in the year or two I've had 'em.


I've had some leak in the packaging and some leak in a torch - 2
different pound shop packs.



Are we still talking NiMHs here, or primary cells? I'd not use cheapie
primary cells for anything.

Primaries - at least I was, and assuming that was what you meant about
Aldi. Might have to go there if they've got NiMH that cheap.

Chris

--
Spamtrap in use
To email replace 127.0.0.1 with btinternet dot com

Chris Hodges November 8th 06 10:10 PM

Rechargeable Batteries
 
Dave Fawthrop wrote:
NiMhs are fine for regularly
used torches cameras, GPSs and other high current uses.

Funny you should say that, my Garmin doesn't like even freshly charged
NiMHs - you get ~3 hours life compared to a quoted 22 from alkalines. 1
walk instead of quite a few.

--
Spamtrap in use
To email replace 127.0.0.1 with btinternet dot com


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