In message , taz
writes
I Beg to differ with you.
I have on occasions, and know friends who have damaged
Ni-Cad batteries. They were damaged by partial depletion
then recharging. They were in sealed waterproof torches
and over a period of time the batteries were damaged by
that method of charging. I now always run my batteries from
full to empty no mater what type.
taz.


Top-up charging is the best regime for NiCd's used in a torch. Full
discharge every time simply wears out the cells unnecessarily.

Of course cells vary enormously in quality and it is virtually
impossible to buy decent ones from retail outlets.

--
Keith Lewis

I agree Keith there are a lot of variables to batteries and the way
they are charged. The trouble with most set-ups IMHO is one cell
will fail in the battery and then the battery as a unit starts to perform
badly. Good cells are hard to get hold of and can easily be damaged
by incorrect use. In my experience if a cell is sold with the label good for
2000 charge cycles I've found that, that number can be reduced by half
if not even 3/4. So in real terms a battery that should be good for 2000
charges sometimes only last for 500 maybe 1000 charges.
Not a scientific answer just my own experience.
taz.


Agreed

Cells are extremely variable and the ones on retail sale tend to give
good ones a bad name. Many are in "D" size cases but are only around
1200 mAH as opposed to an average of 4000 mAH for those available to
OEM's

We've been manufacturing NiCd powered lighting for over 20 years and
have been giving a 3 year guarantee for that time. We do however fit
rather good ones:-)
--
Keith Lewis

Agreed

Cells are extremely variable and the ones on retail sale tend to give
good ones a bad name. Many are in "D" size cases but are only around
1200 mAH as opposed to an average of 4000 mAH for those available to
OEM's

We've been manufacturing NiCd powered lighting for over 20 years and
have been giving a 3 year guarantee for that time. We do however fit
rather good ones:-)
--
Keith Lewis

If I need NiCad cells now I use the ones that power
emergency lights. They come pre-made into batteries
and do seem to be of higher quality.
taz.

In message , taz
writes
Agreed

Cells are extremely variable and the ones on retail sale tend to give
good ones a bad name. Many are in "D" size cases but are only around
1200 mAH as opposed to an average of 4000 mAH for those available to
OEM's

We've been manufacturing NiCd powered lighting for over 20 years and
have been giving a 3 year guarantee for that time. We do however fit
rather good ones:-)
--
Keith Lewis

If I need NiCad cells now I use the ones that power
emergency lights. They come pre-made into batteries
and do seem to be of higher quality.
taz.


They tend to be "high temperature" versions (gets warm in emergency
lighting luminaires) so separator design has to be good. Dendritic
crystal growth through separators is the usual failure mode of Nicd's


--
Keith Lewis

They tend to be "high temperature" versions (gets warm in emergency
lighting luminaires) so separator design has to be good. Dendritic
crystal growth through separators is the usual failure mode of Nicd's


--
Keith Lewis

Is that a white powdery substance. Or I'm I just
thinking of corrosion that forms on the aluminium
casing sometimes.
taz.

In message , taz
writes
They tend to be "high temperature" versions (gets warm in emergency
lighting luminaires) so separator design has to be good. Dendritic
crystal growth through separators is the usual failure mode of Nicd's


--
Keith Lewis

Is that a white powdery substance. Or I'm I just
thinking of corrosion that forms on the aluminium
casing sometimes.
taz.


No its internal and causes tiny short circuits through the separator.
Eventually these raise the self-discharge rate to unmanageable
proportions ( but you will probably find that straight off charge you
still get sufficient capacity).

The cases are nickel plated steel
--
Keith Lewis

No its internal and causes tiny short circuits through the separator.
Eventually these raise the self-discharge rate to unmanageable
proportions ( but you will probably find that straight off charge you
still get sufficient capacity).

The cases are nickel plated steel
--
Keith Lewis

Right I must be getting confused then :-)
Not hard I suppose. I understand what you
are saying about the internal circuits now and
as for the casing I obviously can't tell my nickel
from my ally. Thinking back though and this is me
trying to scratch back some resemblance of intelligence,
our batteries were placed in aluminium bodied torches
and with the added ingredient of see water it could of
been that environment that was causing the corrosion
inside the inside the torch and on the battery.

Well that theory makes sense to me. Yeah good one
taz. taz slinks of congratulating him self on how he
pulled it back without any one noticing. ;-)
Cheers taz.

In message , taz
writes
No its internal and causes tiny short circuits through the separator.
Eventually these raise the self-discharge rate to unmanageable
proportions ( but you will probably find that straight off charge you
still get sufficient capacity).

The cases are nickel plated steel
--
Keith Lewis

Right I must be getting confused then :-)
Not hard I suppose. I understand what you
are saying about the internal circuits now and
as for the casing I obviously can't tell my nickel
from my ally. Thinking back though and this is me
trying to scratch back some resemblance of intelligence,
our batteries were placed in aluminium bodied torches
and with the added ingredient of see water it could of
been that environment that was causing the corrosion
inside the inside the torch and on the battery.

Well that theory makes sense to me. Yeah good one
taz. taz slinks of congratulating him self on how he
pulled it back without any one noticing. ;-)
Cheers taz.


Sounds an excellent corrosive cocktail

Cheers
--
Keith Lewis

In article , taz24taz24
@blueyonder.co.uk says...
They tend to be "high temperature" versions (gets warm in emergency
lighting luminaires) so separator design has to be good. Dendritic
crystal growth through separators is the usual failure mode of Nicd's


--
Keith Lewis

Is that a white powdery substance. Or I'm I just
thinking of corrosion that forms on the aluminium
casing sometimes.
taz.


FWIW, The white powder associated with (leaking/venting) NiCds is
usually potassium hydroxide, a rather caustic material. A chemical
"cousin" is soduim hydroxide (lye). Don't ingest or get in eyes,
needless to say...

Woody

Is that a white powdery substance. Or I'm I just
thinking of corrosion that forms on the aluminium
casing sometimes.
taz.


FWIW, The white powder associated with (leaking/venting) NiCds is
usually potassium hydroxide, a rather caustic material. A chemical
"cousin" is soduim hydroxide (lye). Don't ingest or get in eyes,
needless to say...

Woody

It did tend to sting the skin if it came into contact with it.
taz.

Woody wrote:


FWIW, The white powder associated with (leaking/venting) NiCds is
usually potassium hydroxide

That's actually a bit of a relief. I assumed it had a lot of cadmium in
it, and I'd rather a hydroxide burn than cadmium poisoning!

Andy.