Question on rechargeable batteries

[Michael Muderick]

I have a Dewalt 12 v. rechargeable drill and a Wahl Soldering pencil iron.
New batteries in both - the drill about a year ago, and the iron about two.
I don't use either of them very much. I leave them in the chargers, as
indicated by the manufacturers to be OK. Yet when I do use them, they seem
to die prematurely. I maybe get about 15 good minutes out of the drill, and
2 or 3 connections with the iron.

I was told that because of the memory effect of the batteries, that leaving
them in the chargers when not using them, actually causes this. I should
have just charged them an hour or day before I need them, and not leave them
in the charger. But then they are not ready for use when unexpectedly
needed.

1. Is the damage irreversible?
2. What is the best solution to this problem?

TIA
Michael@muderick.com

 

[Tom]

Possibly reversible.... Run them down , let cool for an hour, and charge for
the prescribed amount of time. Do this a few times- it might increase the
hold.
Then look for a cheap apliance timer- the kind you plug into the wall,
either 24 hour time or 7 day.
Set it to "top-off" your battery while not in normal use. Depending on the
charge current, somewhere between 1 hour/day to 1 hour/week.

Although aimed at nicds for radio controled flying- this website has some
good general info.
http://www.rcbatteryclinic.com/


"Michael Muderick" <mike@muderick.com> wrote in message
news:bio6b.4141$w41.199@nwrdny02.gnilink.net...

I have a Dewalt 12 v. rechargeable drill and a Wahl Soldering pencil iron.
New batteries in both - the drill about a year ago, and the iron about
two.
I don't use either of them very much. I leave them in the chargers, as
indicated by the manufacturers to be OK. Yet when I do use them, they
seem
to die prematurely. I maybe get about 15 good minutes out of the drill,
and
2 or 3 connections with the iron.

I was told that because of the memory effect of the batteries, that
leaving
them in the chargers when not using them, actually causes this. I should
have just charged them an hour or day before I need them, and not leave
them
in the charger. But then they are not ready for use when unexpectedly
needed.

1. Is the damage irreversible?
2. What is the best solution to this problem?

TIA
Michael@muderick.com

 

[JM]

quoting:

I have a Dewalt 12 v. rechargeable drill and a Wahl Soldering pencil iron.
New batteries in both - the drill about a year ago, and the iron about two.
I don't use either of them very much. I leave them in the chargers, as
indicated by the manufacturers to be OK. Yet when I do use them, they seem
to die prematurely. I maybe get about 15 good minutes out of the drill, and
2 or 3 connections with the iron.

Bad advice by the manufacturer. NiCads slowly cook to death if left on the
charger for weeks at a time. If this is the case, then your batteries would
be permantly dead, nothing will bring them back to life. This is not memory,
it's called "overcharge damage".

I was told that because of the memory effect of the batteries, that leaving
them in the chargers when not using them, actually causes this. I should
have just charged them an hour or day before I need them, and not leave them
in the charger. But then they are not ready for use when unexpectedly
needed.

"Memory" happens when a Nicad cell is continually discharged not all the way
dead before being recharged.

1. Is the damage irreversible?

Memory is completely reversable. Overcharge damage is not.

2. What is the best solution to this problem?

Run the drill until it gets slow, then rechagrge. Do that 2 or 3 times, see
if you notice any improvement. If there's no improvement, then it's got to
be overcharge damage, then at that time it will be time to buy new batteries.

 

[Jim Yanik]

"Michael Muderick" <mike@muderick.com> wrote in
news:bio6b.4141$w41.199@nwrdny02.gnilink.net:

I have a Dewalt 12 v. rechargeable drill and a Wahl Soldering pencil
iron. New batteries in both - the drill about a year ago, and the iron
about two. I don't use either of them very much. I leave them in the
chargers, as indicated by the manufacturers to be OK. Yet when I do
use them, they seem to die prematurely. I maybe get about 15 good
minutes out of the drill, and 2 or 3 connections with the iron.

I was told that because of the memory effect of the batteries, that
leaving them in the chargers when not using them, actually causes
this. I should have just charged them an hour or day before I need
them, and not leave them in the charger. But then they are not ready
for use when unexpectedly needed.

1. Is the damage irreversible?
2. What is the best solution to this problem?

TIA
Michael@muderick.com

NiCds like to be USED,not stored. I've had many NiCd packs that lasted
years when used regularly,but when left unused for long periods,failed
quickly.Newer NiMH cells have better characteristics in that respect,I
believe.

For tools that get used infrequently,it may be better/more practical to use
corded tools.

--
Jim Yanik,NRA member
jyanik@kua.net

 

[Michael Muderick]

thanks for the followup answers. I thought the chargers had circuitry to
cut back the charge after charged, and only trickle charge, or go on as
needed. I guess not.
mm