Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
Larry Jaques
 
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Default Rebuilding NICAD Battery Packs

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

TIA.


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Grant Erwin
 
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Larry Jaques wrote:
I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?


It appears that spotwelding is the method of choice for attaching tabs
to nicads. Spotwelding is normally done with, um, a spotwelder. - GWE
  #3   Report Post  
patrick mitchel
 
Posts: n/a
Default

Bah, freeze the cells then do a quicky with a good soldering iron- usually
does the deed without damaging the vent plastic on the top (+) of the cell.-
did the same for a bunch of makita 9.6 stick packs/a drill master 12 v
battery (2 of them) and a 9.6 black and decker. Can get the cells pretty
reasonably at batteryspace.com or american scientific had some 6v-sub c
packs for sale pretty cheap- but used. Pat


  #4   Report Post  
Tim Killian
 
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It's not a good idea to build NiCd packs using cells from different
lots, or to mix used cells with new ones. If one of the cells is
under-capacity versus the rest, it will go into reversal during discharge.


Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

TIA.


================================================== ============
Like peace and quiet? Buy a phoneless cord.
http://www/diversify.com/stees.html Hilarious T-shirts online
================================================== ============


  #5   Report Post  
Jeff Wisnia
 
Posts: n/a
Default

Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

TIA.


================================================== ============
Like peace and quiet? Buy a phoneless cord.
http://www/diversify.com/stees.html Hilarious T-shirts online
================================================== ============


I usually buy cells with solder tabs already spot welded on them, but in
a pinch I've used silver bearing conductive epoxy with excellent
results. The stuff isn't cheap, but a little goes a long way, and you
can store it forever in the kitchen freezer.

I've never felt good about soldering directly to battery cells except
for the old LeClanche carbon-zinc ones, back in the days when most of
the commercially available (greater than 1.5 volt) dry cell batteries
had their individual cells connected together by bare wire soldered to
the zinc cans and brass carbon rod contacts.

Happy Holidays,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"


  #6   Report Post  
patrick mitchel
 
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Tim Killian wrote in message
...
It's not a good idea to build NiCd packs using cells from different
lots, or to mix used cells with new ones. If one of the cells is
under-capacity versus the rest, it will go into reversal during discharge.

Ok, he's got a dead pack(s). If he does put them back together and he gets
one cell that calls it quits, where's he out worse than he was (is?) OTOH if
he manages to good a viable pack that gets him further down the road for a
little sweat equity....cool. Pat


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Tim Wescott
 
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Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

If the cells are that old they're all at end-of-life anyway. Buy all
new cells and build your own pack. Batteries America will cell you
sells (?).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
  #8   Report Post  
Larry Jaques
 
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On Sat, 11 Dec 2004 08:51:18 -0800, Grant Erwin
calmly ranted:

Larry Jaques wrote:
I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?


It appears that spotwelding is the method of choice for attaching tabs
to nicads. Spotwelding is normally done with, um, a spotwelder. - GWE


Everybody needs a little ass, but nobody needs a smart ass.

OK, for the literalists: I don't have a spot welder. What do you
suggest I use?


================================================== ============
Like peace and quiet? Buy a phoneless cord.
http://www/diversify.com/stees.html Hilarious T-shirts online
================================================== ============

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Peter Fairbrother
 
Posts: n/a
Default

Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?


I've never _re_built packs, but I have soldered them together.

The best way I know is to use a hot hammerhead iron - that's a soldering
iron with a bit with two working ends, so you heat both cells at once.

The bit is about 1 inch long and 1/2 inch diameter, and looks like this:

| iron
| ||
| ___||___
| _/ \_
| |_ bit _|
| \________/
|

I have turned a few from copper, it's not hard - unfortunately I don't have
any now, and I can't get back to the shop before mid-Jan (long holidays!).

You really need at least a 40 watt iron, although it can be done with a
smaller one. Wait for it to get hot


People who make up a lot of packs tend to put the cells in the fridge before
soldering, use 60/40 tin/lead solder rather than the leadfree type (naughty,
but then the cells are full of cadmium ...), and make up a frame so the
cells slide easily into the right position. You heat up the ends of two
cells at once, make sure they are wet with solder, remove the iron and
quickly slide one cell to meet the other.

Then cover with heatshrink for mechanical strength.

Never had a problem once I figured out how to do it - and you could of
course practice with the hootered cells first.


It might be worth while googling "hammerhead soldering cell" , some good
links there.

Below is a post I wrote in answer to a similar question, not an immediate
answer but should have some relevant tips.


However, Tim's point about reversal during discharge sounds relevant. I've
always been a good boy and never tried mixing cells tho'. Perhaps you could
try to find the set of cells whose capacities match best.


--
Peter Fairbrother


Hawkey wrote:

Sh*T u aint kidding...30 odd pounds just for the bit!! I think I will
forget it. thanks anyway ;-)


Presuming you want to use it to end-to-end solder a few battery packs, why
not just get a lump of copper, shape it, stick it on the end of an existing
bit, preferably a worn-out one, and use that? You could use tap-and-die to
thread it, or hard solder/braze, or just drill an undersized hole and hammer
it together, whatever seems appropriate and available to attach the lump of
copper. Should be almost free.




Shape. Shape it like the bits you see in photographs, either with the ends
like the end of a flat screwdriver with the tip cut off, or with the ends
round with an extra lump in the middle between the ends. The cross section
area at the middle should be about 3x the area of the working ends.

The bulk of the metal holds the heat, and you want a good but not too good
thermal transfer to the working end - the bulk of the metal is too hot for
the joint, and the heat flowing down the constriction allows it to cool a
little. Possibly more importantly, the thermal constrictions also help
balance the heat flow between the ends, so that one end doesn't suck all the
heat out of the tip.

(the bulk has to be too hot, else when you touched it to the piece to be
soldered it would cool down below the right temperature. The element in the
iron cannot give out heat at the rate the heat flows out at the tip when
soldering, it heats the tip up between making joints. The tip looses heat
from convection and more importantly radiation when it is not making a
joint, but the equilibrium temperature of a fixed wattage iron when left in
air is usually far too hot, which is one reason why you want a Temperature
Controlled iron if you can afford one. Incidently, those spiral wire stands
you sometimes see are partly designed to stop the iron overheating while
switched on but not in immediate use)




Cladding. I usually iron-plate my bits so they will last longer, but I make
sub-millimetre bits with capillary traps [snipped myself, this is long
enough already]. Some people nickel plate, but I don't like to, the finish
is harder to wet with solder, and the chemicals nastier. Actual cladding is
probably beyond the home workshop, but I've never tried.

Anyway, you wouldn't need to bother cladding them - the reason for cladding
is that the solder dissolves the bit, but it would take ages to eat away a
large lump of copper. The tip will oxidise too, but again that will take a
long time to matter, just keep the ends covered in fresh solder. You can
redress it with a file without worrying about filing away the iron layer,
there isn't one , and as it's almost free you can just make a new one if
it ever burns away too much to be used.




You'll still have to buy the iron, I haven't bought one in years so I'm very
out-of-date here, but the Antex TCS, item XY45Y from Maplins at 40, is a 50
watt Temperature Controlled iron. It has the temperature control in the
handle. I haven't used the latest model, but the earlier versions are okay
to use, although the temperature control isn't terribly accurate.

A "proper" adjustable temperature TC iron, which can be controlled within a
few degrees, will have a seperate solder station with a transformer and
electronics, and a few extra wires for a thermocouple in the iron. Maplins
item BP53H is around 50, and seems a good buy. If you are going into
production I'd get a ~100w TC iron and station with fume extraction,
150-ish.


"Gun" type irons are not suitable.


Fixed wattage irons in the 30-250 watt range are easily available, though
not through electronics retailers. I'd suggest 40 watts for joining cells.
The Weller SP40 is the best-known, around 20, and the only iron for which
hammerhead tips are actually available afaik. Cheaper 40W irons are
available for around 10, eg http://www.tooled-up.com/Product.asp?PID=4308
at 7, or http://www.tooled-up.com/Product.asp?PID=28096 at 8. And so on.

By the way, you do not want the "hammerhead" tips that stained glass people
use, they ends are not symmetrical and they are not designed for
simultaneous use of both ends (one way to identify them is that they are
usually bent slightly in the middle).



Another alternative is a butane gas powered iron, about 15; the cheap
versions are usully overpowered and get too hot anyway, adding a large tip
will cool them down to a sensible temperature. Plus you can do repairs in
the field. The tip will be harder to make though.



The cheapest solution? Use a 30 watt mains iron, available from around 2 in
a market, with a large mass tip which you make as above, and leave it a
while to get hot before and between uses. The tips for these are usually
solid copper rods which fit into the barrel, and a hammerhead tip would be
easy to make for this type of iron. A bit of practice and some patience is
needed, but you _can_ do quick joints on cells this way.



A bad "tip" (sorry...), but it might be useful - modern electronic solder is
lead-free, and a good thing too, but if you are only using it very
occasionally then fluxed 60-40 tin/lead solder will probably be a bit easier
to use when soldering cells directly, as it melts at a lower temperature,
wets slightly more easily, and stays liquid a little longer. And you will be
recycling your battery packs, won't you?


YMWV, no matter how good the theory is soldering is an art and needs
practice to get right!

  #10   Report Post  
Larry Jaques
 
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Default

On Sat, 11 Dec 2004 09:51:25 -0800, "patrick mitchel"
calmly ranted:

Bah, freeze the cells then do a quicky with a good soldering iron- usually
does the deed without damaging the vent plastic on the top (+) of the cell.-
did the same for a bunch of makita 9.6 stick packs/a drill master 12 v
battery (2 of them) and a 9.6 black and decker. Can get the cells pretty
reasonably at batteryspace.com or american scientific had some 6v-sub c
packs for sale pretty cheap- but used. Pat


Aren't these stainless cans? I've never had good luck soldering them.
I tried a few years ago and they didn't hold together worth a damn.


================================================== ============
Like peace and quiet? Buy a phoneless cord.
http://www/diversify.com/stees.html Hilarious T-shirts online
================================================== ============



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Larry Jaques
 
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Default

On Sat, 11 Dec 2004 12:17:09 -0800, Tim Wescott
calmly ranted:

Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

If the cells are that old they're all at end-of-life anyway. Buy all
new cells and build your own pack. Batteries America will cell you
sells (?).


I can buy new packs off Ebay for less than I can get new cells
locally. But I hate to toss good cells if they can be put to
use once again. Besides, I'm a tighta^H^H^H^H^H^Hfrugal person.


================================================== ============
Like peace and quiet? Buy a phoneless cord.
http://www/diversify.com/stees.html Hilarious T-shirts online
================================================== ============

  #12   Report Post  
Peter Fairbrother
 
Posts: n/a
Default

reposted, original seems lost in the aether, apologies if double posted

Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?


I've never _re_built packs, but I have soldered them together.

The best way I know is to use a hot hammerhead iron - that's a soldering
iron with a bit with two working ends, so you heat both cells at once.

The bit is about 1 inch long and 1/2 inch diameter, and looks like this:

| iron
| ||
| ___||___
| _/ \_
| |_ bit _|
| \________/
|

I have turned a few from copper, it's not hard - unfortunately I don't have
any now, and I can't get back to the shop before mid-Jan (long holidays!).

You really need at least a 40 watt iron, although it can be done with a
smaller one. Wait for it to get hot


People who make up a lot of packs tend to put the cells in the fridge before
soldering, use 60/40 tin/lead solder rather than the leadfree type (naughty,
but then the cells are full of cadmium ...), and make up a frame so the
cells slide easily into the right position. You heat up the ends of two
cells at once, make sure they are wet with solder, remove the iron and
quickly slide one cell to meet the other.

Then cover with heatshrink for mechanical strength.

Never had a problem once I figured out how to do it - and you could of
course practice with the hootered cells first.


It might be worth while googling "hammerhead soldering cell" , some good
links there.

Below is a post I wrote in answer to a similar question, not an immediate
answer but should have some relevant tips.


However, Tim's point about reversal during discharge sounds relevant. I've
always been a good boy and never tried mixing cells tho'. Perhaps you could
try to find the set of cells whose capacities match best.


--
Peter Fairbrother


Hawkey wrote:

Sh*T u aint kidding...30 odd pounds just for the bit!! I think I will
forget it. thanks anyway ;-)


Presuming you want to use it to end-to-end solder a few battery packs, why
not just get a lump of copper, shape it, stick it on the end of an existing
bit, preferably a worn-out one, and use that? You could use tap-and-die to
thread it, or hard solder/braze, or just drill an undersized hole and hammer
it together, whatever seems appropriate and available to attach the lump of
copper. Should be almost free.




Shape. Shape it like the bits you see in photographs, either with the ends
like the end of a flat screwdriver with the tip cut off, or with the ends
round with an extra lump in the middle between the ends. The cross section
area at the middle should be about 3x the area of the working ends.

The bulk of the metal holds the heat, and you want a good but not too good
thermal transfer to the working end - the bulk of the metal is too hot for
the joint, and the heat flowing down the constriction allows it to cool a
little. Possibly more importantly, the thermal constrictions also help
balance the heat flow between the ends, so that one end doesn't suck all the
heat out of the tip.

(the bulk has to be too hot, else when you touched it to the piece to be
soldered it would cool down below the right temperature. The element in the
iron cannot give out heat at the rate the heat flows out at the tip when
soldering, it heats the tip up between making joints. The tip looses heat
from convection and more importantly radiation when it is not making a
joint, but the equilibrium temperature of a fixed wattage iron when left in
air is usually far too hot, which is one reason why you want a Temperature
Controlled iron if you can afford one. Incidently, those spiral wire stands
you sometimes see are partly designed to stop the iron overheating while
switched on but not in immediate use)




Cladding. I usually iron-plate my bits so they will last longer, but I make
sub-millimetre bits with capillary traps [snipped myself, this is long
enough already]. Some people nickel plate, but I don't like to, the finish
is harder to wet with solder, and the chemicals nastier. Actual cladding is
probably beyond the home workshop, but I've never tried.

Anyway, you wouldn't need to bother cladding them - the reason for cladding
is that the solder dissolves the bit, but it would take ages to eat away a
large lump of copper. The tip will oxidise too, but again that will take a
long time to matter, just keep the ends covered in fresh solder. You can
redress it with a file without worrying about filing away the iron layer,
there isn't one , and as it's almost free you can just make a new one if
it ever burns away too much to be used.




You'll still have to buy the iron, I haven't bought one in years so I'm very
out-of-date here, but the Antex TCS, item XY45Y from Maplins at 40, is a 50
watt Temperature Controlled iron. It has the temperature control in the
handle. I haven't used the latest model, but the earlier versions are okay
to use, although the temperature control isn't terribly accurate.

A "proper" adjustable temperature TC iron, which can be controlled within a
few degrees, will have a seperate solder station with a transformer and
electronics, and a few extra wires for a thermocouple in the iron. Maplins
item BP53H is around 50, and seems a good buy. If you are going into
production I'd get a ~100w TC iron and station with fume extraction,
150-ish.


"Gun" type irons are not suitable.


Fixed wattage irons in the 30-250 watt range are easily available, though
not through electronics retailers. I'd suggest 40 watts for joining cells.
The Weller SP40 is the best-known, around 20, and the only iron for which
hammerhead tips are actually available afaik. Cheaper 40W irons are
available for around 10, eg http://www.tooled-up.com/Product.asp?PID=4308
at 7, or http://www.tooled-up.com/Product.asp?PID=28096 at 8. And so on.

By the way, you do not want the "hammerhead" tips that stained glass people
use, they ends are not symmetrical and they are not designed for
simultaneous use of both ends (one way to identify them is that they are
usually bent slightly in the middle).



Another alternative is a butane gas powered iron, about 15; the cheap
versions are usully overpowered and get too hot anyway, adding a large tip
will cool them down to a sensible temperature. Plus you can do repairs in
the field. The tip will be harder to make though.



The cheapest solution? Use a 30 watt mains iron, available from around 2 in
a market, with a large mass tip which you make as above, and leave it a
while to get hot before and between uses. The tips for these are usually
solid copper rods which fit into the barrel, and a hammerhead tip would be
easy to make for this type of iron. A bit of practice and some patience is
needed, but you _can_ do quick joints on cells this way.



A bad "tip" (sorry...), but it might be useful - modern electronic solder is
lead-free, and a good thing too, but if you are only using it very
occasionally then fluxed 60-40 tin/lead solder will probably be a bit easier
to use when soldering cells directly, as it melts at a lower temperature,
wets slightly more easily, and stays liquid a little longer. And you will be
recycling your battery packs, won't you?


YMWV, no matter how good the theory is soldering is an art and needs
practice to get right!

  #13   Report Post  
Bob May
 
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I've done a bit of rebuilding myself. What I've done is to make sure that I
solder to the tab left over after I've cut it free from the bad cell. This
keeps the heat down on the cell itself. I also use a good hot iron and work
quickly, first tinning the tab and then letting the battery get back to
normal before soldering the two batteries together.

--
Why isn't there an Ozone Hole at the NORTH Pole?


  #14   Report Post  
Tim Wescott
 
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Larry Jaques wrote:

I can buy new packs off Ebay for less than I can get new cells
locally. But I hate to toss good cells if they can be put to
use once again. Besides, I'm a tighta^H^H^H^H^H^Hfrugal person.

I guess the point is that they're not good cells at this point --
they're just cells that haven't given up quite yet.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
  #15   Report Post  
ATP
 
Posts: n/a
Default


"Larry Jaques" wrote in message
...
I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

TIA.

You might be able to find new packs on ebay at a very decent price.




  #16   Report Post  
Larry Jaques
 
Posts: n/a
Default

On Sun, 12 Dec 2004 00:37:41 +0000, Peter Fairbrother
calmly ranted:

reposted, original seems lost in the aether, apologies if double posted


It came through, too.


Larry Jaques wrote:


Who here has rebuilt packs and how did you attach the cells?


I've never _re_built packs, but I have soldered them together.


OK, I'll see what I have in real solder and give it a try on the
old dead cells. I don't need the double head because I'll keep the
tab on the good cell to affix to the new pack.


You really need at least a 40 watt iron, although it can be done with a
smaller one. Wait for it to get hot


I have a brand new 100w stained glass iron, temp controller, and flux,
but I'll probably use the Weller soldering gun.


People who make up a lot of packs tend to put the cells in the fridge before
soldering, use 60/40 tin/lead solder rather than the leadfree type (naughty,
but then the cells are full of cadmium ...), and make up a frame so the
cells slide easily into the right position. You heat up the ends of two
cells at once, make sure they are wet with solder, remove the iron and
quickly slide one cell to meet the other.

Then cover with heatshrink for mechanical strength.


It comes with a plastic cover and a fiber/mica shield on top. Both
are reusable.


Never had a problem once I figured out how to do it - and you could of
course practice with the hootered cells first.


Hootered cells? I didn't know there were male and female NiCads.
g (See www.Hooters.com for our idea of what that word means.)
chuckle


However, Tim's point about reversal during discharge sounds relevant. I've
always been a good boy and never tried mixing cells tho'. Perhaps you could
try to find the set of cells whose capacities match best.


Both packs were in the same kit originally and may even be from the
same batch, so that may not be a problem.

Thanks, all. (But where are the fake spotwelder recipes?)



--

From time to time, we have been tempted to believe that society has
become too complex to be managed by self-rule, that government by
an elite group is superior to government for, by, and of the people.
But if no one among us is capable of governing himself, then who
among us has the capacity to govern someone else?
All of us together, in and out of government, must bear the
burden. The solutions we seek must be equitable, with no one
group singled out to pay a higher price.

-President Ronald Reagan
First Inaugural Address
Tuesday, January 20, 1981

  #17   Report Post  
Larry Jaques
 
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On Sat, 11 Dec 2004 16:50:47 -0800, Tim Wescott
calmly ranted:

Larry Jaques wrote:

I can buy new packs off Ebay for less than I can get new cells
locally. But I hate to toss good cells if they can be put to
use once again. Besides, I'm a tighta^H^H^H^H^H^Hfrugal person.

I guess the point is that they're not good cells at this point --
they're just cells that haven't given up quite yet.


They're only about 2.5 years old and have had maybe 50 charges
each, so my guess is that they still have life in them.
Of course, I'll reglue a sneaker whose sole tried to fall off
if the uppers are in good condition, too. YMMV.


--

From time to time, we have been tempted to believe that society has
become too complex to be managed by self-rule, that government by
an elite group is superior to government for, by, and of the people.
But if no one among us is capable of governing himself, then who
among us has the capacity to govern someone else?
All of us together, in and out of government, must bear the
burden. The solutions we seek must be equitable, with no one
group singled out to pay a higher price.

-President Ronald Reagan
First Inaugural Address
Tuesday, January 20, 1981

  #18   Report Post  
Old Nick
 
Posts: n/a
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On Sat, 11 Dec 2004 20:29:10 -0500, "ATP"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

(1) You might look at NiMH cells as replacements. I know this is not
in answer to your question, but you get a HEAP more energy per
charge.....= longer running.


You might be able to find new packs on ebay at a very decent price.


But buy only a few until you have tested them, and NEVER buy Titanium
brand.

I bought 16 from bloody Ebay, and well over half got very hot and
leaked when charged -by the charger supplied by the battery vendor-,
and also on my other smart charger that had successfully charged many
a NiMH until then. I returned them (postage starting to eat into
"savings") and they came back "tested"...with the crystalline crap
still showing on them!

Never again. Maybe my loss, but I have had one good, and two bad,
encounters with dealers on Ebay. Enough.

I never even had a reply on the lack of the 4 x AA NiMH cells I was
supposed to get with the charger.

I found a few other complaints about these Titanium brand. They claim
a .1% failure rate or something. Well in that case, suck it up guys,
and keep sending me new ones until I get decent bloody cells!

Oh yeah, and the rating system. This mob that sold to me had a 98.7%
favourable rating. So maybe I am just the unluckiest SOB on the Net.
---
Only worry about the things you can control.

Then you have stuff all to worry about!
  #19   Report Post  
Spehro Pefhany
 
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On Sun, 12 Dec 2004 12:08:40 +0800, the renowned Old Nick
wrote:

I found a few other complaints about these Titanium brand. They claim
a .1% failure rate or something. Well in that case, suck it up guys,
and keep sending me new ones until I get decent bloody cells!


There's circumstantial evidence that counterfeit Sony NiMH cells are
being sold on eBay. They have markedly lower capacity than the real
Sony cells.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
  #20   Report Post  
Martin H. Eastburn
 
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Bob May wrote:

I've done a bit of rebuilding myself. What I've done is to make sure that I
solder to the tab left over after I've cut it free from the bad cell. This
keeps the heat down on the cell itself. I also use a good hot iron and work
quickly, first tinning the tab and then letting the battery get back to
normal before soldering the two batteries together.

--
Why isn't there an Ozone Hole at the NORTH Pole?


Yep - what everyone is talking about a hot iron is not temperature, but
the temp after putting it on a sink.

This really indicates a large or massive (physically) heater and tip.
It might be a 100 or 150 watt iron. Notice this isn't the temp like 700 degree.
One would expect these to reach that temp easily after warm up time.

File the tip clean - and use the heal of your shoe (inside parts to keep them
looking nice) as a shield. This melted rubber (stinks a little) coats the
iron so solder won't run all over the tip or the back...
Have a area the size needed tinned once the rest is shielded.

Martin
[ who owns a 100 Watt Black Beauty and gave his 300 watt to a friend doing gutters ]

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder


  #21   Report Post  
Peter Fairbrother
 
Posts: n/a
Default

and again, maybe third time lucky!

reposted, original seems lost in the aether, apologies if double posted

Larry Jaques wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?


I've never _re_built packs, but I have soldered them together.

The best way I know is to use a hot hammerhead iron - that's a soldering
iron with a bit with two working ends, so you heat both cells at once.

The bit is about 1 inch long and 1/2 inch diameter, and looks like this:

| iron
| ||
| ___||___
| _/ \_
| |_ bit _|
| \________/
|

I have turned a few from copper, it's not hard - unfortunately I don't have
any now, and I can't get back to the shop before mid-Jan (long holidays!).

You really need at least a 40 watt iron, although it can be done with a
smaller one. Wait for it to get hot


People who make up a lot of packs tend to put the cells in the fridge before
soldering, use 60/40 tin/lead solder rather than the leadfree type (naughty,
but then the cells are full of cadmium ...), and make up a frame so the
cells slide easily into the right position. You heat up the ends of two
cells at once, make sure they are wet with solder, remove the iron and
quickly slide one cell to meet the other.

Then cover with heatshrink for mechanical strength.

Never had a problem once I figured out how to do it - and you could of
course practice with the hootered cells first.


It might be worth while googling "hammerhead soldering cell" , some good
links there.

Below is a post I wrote in answer to a similar question, not an immediate
answer but should have some relevant tips.


However, Tim's point about reversal during discharge sounds relevant. I've
always been a good boy and never tried mixing cells tho'. Perhaps you could
try to find the set of cells whose capacities match best.


--
Peter Fairbrother


Hawkey wrote:

Sh*T u aint kidding...30 odd pounds just for the bit!! I think I will
forget it. thanks anyway ;-)


Presuming you want to use it to end-to-end solder a few battery packs, why
not just get a lump of copper, shape it, stick it on the end of an existing
bit, preferably a worn-out one, and use that? You could use tap-and-die to
thread it, or hard solder/braze, or just drill an undersized hole and hammer
it together, whatever seems appropriate and available to attach the lump of
copper. Should be almost free.




Shape. Shape it like the bits you see in photographs, either with the ends
like the end of a flat screwdriver with the tip cut off, or with the ends
round with an extra lump in the middle between the ends. The cross section
area at the middle should be about 3x the area of the working ends.

The bulk of the metal holds the heat, and you want a good but not too good
thermal transfer to the working end - the bulk of the metal is too hot for
the joint, and the heat flowing down the constriction allows it to cool a
little. Possibly more importantly, the thermal constrictions also help
balance the heat flow between the ends, so that one end doesn't suck all the
heat out of the tip.

(the bulk has to be too hot, else when you touched it to the piece to be
soldered it would cool down below the right temperature. The element in the
iron cannot give out heat at the rate the heat flows out at the tip when
soldering, it heats the tip up between making joints. The tip looses heat
from convection and more importantly radiation when it is not making a
joint, but the equilibrium temperature of a fixed wattage iron when left in
air is usually far too hot, which is one reason why you want a Temperature
Controlled iron if you can afford one. Incidently, those spiral wire stands
you sometimes see are partly designed to stop the iron overheating while
switched on but not in immediate use)




Cladding. I usually iron-plate my bits so they will last longer, but I make
sub-millimetre bits with capillary traps [snipped myself, this is long
enough already]. Some people nickel plate, but I don't like to, the finish
is harder to wet with solder, and the chemicals nastier. Actual cladding is
probably beyond the home workshop, but I've never tried.

Anyway, you wouldn't need to bother cladding them - the reason for cladding
is that the solder dissolves the bit, but it would take ages to eat away a
large lump of copper. The tip will oxidise too, but again that will take a
long time to matter, just keep the ends covered in fresh solder. You can
redress it with a file without worrying about filing away the iron layer,
there isn't one , and as it's almost free you can just make a new one if
it ever burns away too much to be used.




You'll still have to buy the iron, I haven't bought one in years so I'm very
out-of-date here, but the Antex TCS, item XY45Y from Maplins at 40, is a 50
watt Temperature Controlled iron. It has the temperature control in the
handle. I haven't used the latest model, but the earlier versions are okay
to use, although the temperature control isn't terribly accurate.

A "proper" adjustable temperature TC iron, which can be controlled within a
few degrees, will have a seperate solder station with a transformer and
electronics, and a few extra wires for a thermocouple in the iron. Maplins
item BP53H is around 50, and seems a good buy. If you are going into
production I'd get a ~100w TC iron and station with fume extraction,
150-ish.


"Gun" type irons are not suitable.


Fixed wattage irons in the 30-250 watt range are easily available, though
not through electronics retailers. I'd suggest 40 watts for joining cells.
The Weller SP40 is the best-known, around 20, and the only iron for which
hammerhead tips are actually available afaik. Cheaper 40W irons are
available for around 10, eg http://www.tooled-up.com/Product.asp?PID=4308
at 7, or http://www.tooled-up.com/Product.asp?PID=28096 at 8. And so on.

By the way, you do not want the "hammerhead" tips that stained glass people
use, they ends are not symmetrical and they are not designed for
simultaneous use of both ends (one way to identify them is that they are
usually bent slightly in the middle).



Another alternative is a butane gas powered iron, about 15; the cheap
versions are usully overpowered and get too hot anyway, adding a large tip
will cool them down to a sensible temperature. Plus you can do repairs in
the field. The tip will be harder to make though.



The cheapest solution? Use a 30 watt mains iron, available from around 2 in
a market, with a large mass tip which you make as above, and leave it a
while to get hot before and between uses. The tips for these are usually
solid copper rods which fit into the barrel, and a hammerhead tip would be
easy to make for this type of iron. A bit of practice and some patience is
needed, but you _can_ do quick joints on cells this way.



A bad "tip" (sorry...), but it might be useful - modern electronic solder is
lead-free, and a good thing too, but if you are only using it very
occasionally then fluxed 60-40 tin/lead solder will probably be a bit easier
to use when soldering cells directly, as it melts at a lower temperature,
wets slightly more easily, and stays liquid a little longer. And you will be
recycling your battery packs, won't you?


YMWV, no matter how good the theory is soldering is an art and needs
practice to get right!

  #22   Report Post  
Jerry Martes
 
Posts: n/a
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Larry

Try a little Stay-Clean (a Harris proiduct) as the flux next time you want
to soft solder stainless. It makes soft soldering stainless easy.

I have been successfull with soldering tabs on all the "good quality"
batteries I've worked with. I have ruined some "import/low cost" cells by
overheating them with the soldering iron.

Jerry

"Larry Jaques" wrote in message
...
On Sat, 11 Dec 2004 09:51:25 -0800, "patrick mitchel"
calmly ranted:

Bah, freeze the cells then do a quicky with a good soldering iron- usually
does the deed without damaging the vent plastic on the top (+) of the
cell.-
did the same for a bunch of makita 9.6 stick packs/a drill master 12 v
battery (2 of them) and a 9.6 black and decker. Can get the cells pretty
reasonably at batteryspace.com or american scientific had some 6v-sub c
packs for sale pretty cheap- but used. Pat


Aren't these stainless cans? I've never had good luck soldering them.
I tried a few years ago and they didn't hold together worth a damn.


================================================== ============
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  #23   Report Post  
Old Nick
 
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On Sun, 12 Dec 2004 06:49:31 +0000, Peter Fairbrother
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

and again, maybe third time lucky!

reposted, original seems lost in the aether, apologies if double posted


We have seen all 3 posts, or I have.
---
Only worry about the things you can control.

Then you have stuff all to worry about!
  #24   Report Post  
patrick mitchel
 
Posts: n/a
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Larry Jaques wrote in message
Aren't these stainless cans? I've never had good luck soldering them.
I tried a few years ago and they didn't hold together worth a damn.

If they are stainless, I havent had a problem getting the solder to stick.I
was using a weller soldering gun (140 watts I think) with some thick copper
wire as the tip. Some of the cells have exhibited rust when left to the
elements.I usualy hit the area to be soldered with a coarse sandpaper, and
use a "nokorode" soldering flux- cleaning the flux off afterwards. I try to
peel the solder tabs off the dead cells with some needle nose pliers.
Usually successful. I tried to solder the cells directly without the solder
tabs but found that if you drop the pack : ( then the solder joint breaks- I
guess since there isn't any flex in the solder.The whole idea of tossing
something in the waste stream just because it isn't a hunnert % any longer,
old or cheap just doesn't cut it with me. There's always more things to
spend money on than there is money...(plastic non withstanding) Pat


  #25   Report Post  
 
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On Sat, 11 Dec 2004 08:24:54 -0800, Larry Jaques
wrote:

I recently replaced one of the two dead Ryobi 14.4v batt packs which
several years of abuse before dying on me. It appears that just a few
of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.

Who here has rebuilt packs and how did you attach the cells?

TIA.

Soldering works fine if you use a hot iron (at least
20w) and complete the joint in no more than two or three
seconds. Use 60-40 lead/tin solder and an active flux -
Bakers soldering fluid or similar killed acid type flux so
that you get immediate solder wetting.

Use the solder connection for electrical
continuity only.For mechanical retention use epoxy resin
assisted as appropriate by duct tape or shrink wrap.

Jim





  #26   Report Post  
Larry Jaques
 
Posts: n/a
Default

On Sun, 12 Dec 2004 06:49:31 +0000, Peter Fairbrother
calmly ranted:

and again, maybe third time lucky!

reposted, original seems lost in the aether, apologies if double posted


Triple-posted.


--

From time to time, we have been tempted to believe that society has
become too complex to be managed by self-rule, that government by
an elite group is superior to government for, by, and of the people.
But if no one among us is capable of governing himself, then who
among us has the capacity to govern someone else?
All of us together, in and out of government, must bear the
burden. The solutions we seek must be equitable, with no one
group singled out to pay a higher price.

-President Ronald Reagan
First Inaugural Address
Tuesday, January 20, 1981

  #27   Report Post  
Ted Edwards
 
Posts: n/a
Default

Larry Jaques wrote:

of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.


I see anumber of suggestions about soldering cells together directly.
IMO, this is a very bad idea. I've never ssen a comercial pack done
this way. If successful at all, any vibration or mechanical stress
would almost certainly either cause the connection to fail or damage the
top of the cell.

If you are going to try soldering, use bit of copper braid, preferably
pre-tinned such as a bit of the shield braid off a piece of coax. Cut
off a length about equal to a cell diameter, tin the very ends and bend
in the middle to form a broad V. Tin the cell ends in a small area.
Work quickly with a hot iron. solder one end of the braid to the
positive end of one cell. Slip a plastic insulating disc over the braid
to prevent shorts. Solder the other end of the braid to the other
cell's negative then fold to make a compact joint.

And, yes, I do plan to build me a capacitor discharge spot welder but I
won't give out the circuit 'til I've designed, built and tried it.

Ted


  #28   Report Post  
Larry Jaques
 
Posts: n/a
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On Mon, 13 Dec 2004 00:08:07 GMT, Ted Edwards
calmly ranted:

Larry Jaques wrote:

of the dozen cells in each pack have gone bye-bye. I'd like to rebuild
one from the dregs of the other and wondered what you guys used to
spotweld the cells together. I've heard that they don't like to be
soldered _at_all_.


I see anumber of suggestions about soldering cells together directly.
IMO, this is a very bad idea. I've never ssen a comercial pack done
this way. If successful at all, any vibration or mechanical stress
would almost certainly either cause the connection to fail or damage the
top of the cell.


Good point there, Ted.


If you are going to try soldering, use bit of copper braid, preferably
pre-tinned such as a bit of the shield braid off a piece of coax. Cut
off a length about equal to a cell diameter, tin the very ends and bend
in the middle to form a broad V. Tin the cell ends in a small area.
Work quickly with a hot iron. solder one end of the braid to the
positive end of one cell. Slip a plastic insulating disc over the braid
to prevent shorts. Solder the other end of the braid to the other
cell's negative then fold to make a compact joint.


Used desoldering wick works well for that. BTDT, fixed the Bose 501
woofer carbon leads that way twice in the last decade and a half.


And, yes, I do plan to build me a capacitor discharge spot welder but I
won't give out the circuit 'til I've designed, built and tried it.


OK, I'll give you until (how does next Wednesday sound?) to do that.



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