Got a nicad battery pack to replace in a small loran set. It has 7
individual cells that are in series hookup by means of thin straps soldered
on tops and bottoms of pair, and wires coming off the pack to a small plug.

The replacement battery pack doesn't have the wires needed, so it looks like
I'm going to have to transfer the ones on the old/bad pack to the new/good
pack.

These wires were soldered onto the positive and negative battery contacts.
The question being how can I do that without damaging the batteries? My old
soldering stuff is too hot to use on these delicate things. So, what do I
go to for this task?

In article ,
"RB" wrote:

Got a nicad battery pack to replace in a small loran set. It has 7
individual cells that are in series hookup by means of thin straps soldered
on tops and bottoms of pair, and wires coming off the pack to a small plug.

The replacement battery pack doesn't have the wires needed, so it looks like
I'm going to have to transfer the ones on the old/bad pack to the new/good
pack.

These wires were soldered onto the positive and negative battery contacts.
The question being how can I do that without damaging the batteries? My old
soldering stuff is too hot to use on these delicate things. So, what do I
go to for this task?

Your old soldering stuff isn't too hot, but if the tip isn't SHINY,
replace it. Scuff the battery with steel wool or scotchbrite or an
X-acto knife. Use some good rosin flux! (Required!) You should be able
to solder a small dollop of solder onto the battery very quickly. Then,
put another drop of flux on top of the solder, set the stripped and
tinned wire end into the flux drop, and reflow the solder.

If you have trouble with the rosin core solder ... I've found that acid core
(plumbing) solder works well for soldering to the large, flat NiCad battery
case area. I know that purists will reply here that acid core flux is not
desirable for electronic applications due to the fact that the acid is
corrosive. But I'd ask these people to keep in mind that most batteries
will only last a few years so a 40-year life is not essential in this
application. So, if you can't get the solder to hold to the case with rosin
flux, try cleaning the area and using acid flux instead. Also, minimize the
time that the soldering iron is in contact with the case so you do not
damage the new battery and as suggested, use a well tinned iron.

Bob


"Smitty Two" wrote in message
news
Your old soldering stuff isn't too hot, but if the tip isn't SHINY,
replace it. Scuff the battery with steel wool or scotchbrite or an
X-acto knife. Use some good rosin flux! (Required!) You should be able
to solder a small dollop of solder onto the battery very quickly. Then,
put another drop of flux on top of the solder, set the stripped and
tinned wire end into the flux drop, and reflow the solder.

Your local Batteries Plus will spot-weld a pair of solder tabs onto a NiCd
cell for about $1.

RB wrote:
Got a nicad battery pack to replace in a small loran set. It has 7
individual cells that are in series hookup by means of thin straps soldered
on tops and bottoms of pair, and wires coming off the pack to a small plug.

The replacement battery pack doesn't have the wires needed, so it looks like
I'm going to have to transfer the ones on the old/bad pack to the new/good
pack.

These wires were soldered onto the positive and negative battery contacts.
The question being how can I do that without damaging the batteries? My old
soldering stuff is too hot to use on these delicate things. So, what do I
go to for this task?




It's generally not advisable to solder directly to nicad batteries. If
you do it, you want a real hot soldering iron and prep the surface well
first so the heat can be on it as short a time as possible but unless it
has tabs I don't recommend it.

On 14-Jan-2006, James Sweet wrote:

It's generally not advisable to solder directly to nicad batteries. If
you do it, you want a real hot soldering iron and prep the surface well
first so the heat can be on it as short a time as possible but unless it
has tabs I don't recommend it.

I've been making up battery packs for some of the Sony "Micro" radios lately
and agree with what James says. After having a maybe 50% success rate
soldering directly to the battery, I now have my local "Battery World" put
tags on the individual cells - they do the neatest spot welding ever. Well
worth the extra few pennies. BTW, MiMH cells are usually available in the
same physical size as the NiCads, they have a little extra capacity, don't
have as drastic a "memory" as the NiCads and do have the same voltage.
Worth looking at. Works for me, YMMV.

Haggis.

In article ,
Smitty Two wrote:
Your old soldering stuff isn't too hot

.... in fact, it's more likely to be too puny, leading to you sitting there
trying to solder it for 30 seconds, cooking the battery in the process.

A nice BIG iron, used QUICKLY is much preferable to a tiddly little
"safety" iron
--
--------------------------------------+------------------------------------
Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/

In article 1a8yf.79633$OU5.3863@clgrps13,
"Haggis" wrote:

On 14-Jan-2006, James Sweet wrote:

It's generally not advisable to solder directly to nicad batteries. If
you do it, you want a real hot soldering iron and prep the surface well
first so the heat can be on it as short a time as possible but unless it
has tabs I don't recommend it.

I've been making up battery packs for some of the Sony "Micro" radios lately
and agree with what James says. After having a maybe 50% success rate
soldering directly to the battery,

--snip--

At the hardware store, you can find a little "kit" (plastic bubble on a
cardboard backing) put out by Alpha solder (I think) that is a piece of
solid-core solder wrapped around a tube of flux. The stuff is advertised
for "non-electrical repairs", and mentions stainless steel. Makes it
easy to attach wires to NiCd cases. They make several of those kits, for
various uses; make sure you get the right one.

The flux is as runny as water, so *watch out*. Saturate a cotton swab
with the stuff, kind of "scrub" it onto the cell, and tin quickly with
the supplied solder and a hot, clean iron (I use a 100 watt gun). After
it's tinned, you can attach the wires using regular electronic solder.

No relationship, just a happy customer.

Isaac