[SMS]

In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out
my high-current power supply and zapped each cell 20 times. The packs
both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at once.
Also this is not for NiMH cells or Li-Ion cells, only NiCad cells.

[gregz]

SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out my
high-current power supply and zapped each cell 20 times. The packs both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads because
you must zap each individual cell, not the entire pack at once. Also this
is not for NiMH cells or Li-Ion cells, only NiCad cells.

I never had luck at maintaing operating voltage. If you don't run down the
cells much, you might get by. They will try to go back to the shorted
condition. I would say keep them on charge, but that is another reason they
go ad. Good luck.

Greg

[[email protected][_2_]]

On May 30, 6:08*pm, gregz wrote:
SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out my
high-current power supply and zapped each cell 20 times. The packs both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads because
you must zap each individual cell, not the entire pack at once. Also this
is not for NiMH cells or Li-Ion cells, only NiCad cells.

I never had luck at maintaing operating voltage. If you don't run down the
cells much, you might get by. They will try to go back to the shorted
condition. I would say keep them on charge, but that is another reason they
go ad. Good luck.

Greg

IMO, once you dissassemble the battery pack, what's
the point? The zapping may get you some more life,
but it's not like it;s a new set of batteries. And
considering the effort in taking apart and putting it
back together, I'd just go with new. You can buy new
batteries to replace them with on Ebay. I did that last
year with my Dewalt driver/drill. For $17 it's better
than when it was new 30 years ago.

[bob haller]

On May 30, 6:34*pm, "
wrote:
On May 30, 6:08*pm, gregz wrote:





SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out my
high-current power supply and zapped each cell 20 times. The packs both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads because
you must zap each individual cell, not the entire pack at once. Also this
is not for NiMH cells or Li-Ion cells, only NiCad cells.

I never had luck at maintaing operating voltage. If you don't run down the
cells much, you might get by. They will try to go back to the shorted
condition. I would say keep them on charge, but that is another reason they
go ad. Good luck.

Greg

IMO, once you dissassemble the battery pack, what's
the point? *The zapping may get you some more life,
but it's not like it;s a new set of batteries. *And
considering the effort in taking apart and putting it
back together, I'd just go with new. *You can buy new
batteries to replace them with on Ebay. *I did that last
year with my Dewalt driver/drill. *For $17 it's better
than when it was new 30 years ago.

or get the pack rebuilt by PRIMECELL.COM, higher capacity cells and
fresh too

[harry]

On May 30, 10:47*pm, SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out
my high-current power supply and zapped each cell 20 times. The packs
both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at once.
Also this is not for NiMH cells or Li-Ion cells, only NiCad cells.

"Whiskers" of cadmium metal short the cells out.
Zapping them just blows the whiskers apart.
Sometimes works.

[Jim Yanik]

gregz wrote in

rg:

SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in
each) that wouldn't charge (charger gave the fast blink error). I
hauled out my high-current power supply and zapped each cell 20
times. The packs both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at
once. Also this is not for NiMH cells or Li-Ion cells, only NiCad
cells.

I never had luck at maintaing operating voltage. If you don't run down
the cells much, you might get by. They will try to go back to the
shorted condition. I would say keep them on charge, but that is
another reason they go ad. Good luck.

Greg


I suggest he find a local battery rebuilder and have them redone right
with new cells.
Or if your charger can handle them,get higher capacity NiMH cells
installed.

they don't short like NiCds do.

--
Jim Yanik
jyanik
at
localnet
dot com

[[email protected]]

On Thu, 31 May 2012 07:59:10 -0700 (PDT), harry wrote:

On May 30, 10:47*pm, SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out
my high-current power supply and zapped each cell 20 times. The packs
both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at once.
Also this is not for NiMH cells or Li-Ion cells, only NiCad cells.

"Whiskers" of cadmium metal short the cells out.
Zapping them just blows the whiskers apart.

Since the whisker grew in the first place, it'll grow right back.

Sometimes works.

Sometimes. For a short time. Bottom line; replace the cells.

[hr(bob) [email protected]]

On May 31, 10:33*am, "
wrote:
On Thu, 31 May 2012 07:59:10 -0700 (PDT), harry wrote:
On May 30, 10:47*pm, SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out
my high-current power supply and zapped each cell 20 times. The packs
both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at once..
Also this is not for NiMH cells or Li-Ion cells, only NiCad cells.

"Whiskers" of cadmium metal short the cells out.
Zapping them just blows the whiskers apart.

Since the whisker grew in the first place, it'll grow right back.

Sometimes works.

Sometimes. *For a short time. *Bottom line; replace the cells.

If you can keep the battery pack on a constant ;low charge, that will
usually prevent the wiskers from forming a real short, it apparantly
burns them off oas the just get to the shorting point. But if no
constant charging, then good luck.

[[email protected]]

On Thu, 31 May 2012 10:33:36 -0700 (PDT), "hr(bob) "
wrote:

On May 31, 10:33*am, "
wrote:
On Thu, 31 May 2012 07:59:10 -0700 (PDT), harry wrote:
On May 30, 10:47*pm, SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out
my high-current power supply and zapped each cell 20 times. The packs
both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at once.
Also this is not for NiMH cells or Li-Ion cells, only NiCad cells.

"Whiskers" of cadmium metal short the cells out.
Zapping them just blows the whiskers apart.

Since the whisker grew in the first place, it'll grow right back.

Sometimes works.

Sometimes. *For a short time. *Bottom line; replace the cells.

If you can keep the battery pack on a constant ;low charge, that will
usually prevent the wiskers from forming a real short, it apparantly
burns them off oas the just get to the shorting point. But if no
constant charging, then good luck.

Requiring a constant charge makes a batteries pretty useless. ;-)

The point being, that once a dendrite forms, it's made a channel through the
insulator. After (part of) that dendrite is burned out, another will quickly
form because 1) the insulation barrier is compromised, and 2) because the
dendrite isn't completely gone. It will regrow quickly.