On Thu, 20 Dec 2012 13:50:40 -0800 (PST), in sci.electronics.repair you wrote:

On Dec 20, 12:38 pm, Bob E. wrote:
Do what Mr. Cook suggests, it is what I frequently do.

I second this. I've done this several times with "non-replaceable" cells in
shavers, etc. and have had no failures related to quick-soldering, only the
usual slow degradation over time of the cell chemistry.

Tin the wire, emery-paper the terminals, clean, drop of flux, quick solder.

Also, use fairly small wire for the attachment and put a tiny blob
of solder on the wire to be attached... Then a quick touch with
the iron will melt both blobs together. The secret is minimum heat
and time, but it is easy to do...... and be sure to use the
emery paper on the batt terminals first....

Hi Andy,

I decided to do what the majority of respondents recommended.

I have a 200/260W Weller solder gun and when I gave it some thought,
when someone spot welds a tab onto the battery, it creates a momentary
hot spot on the battery. The Weller gun can't to worse than a spot weld as
long as the time is short and proper preparation is made.

By golly, I had no trouble at all and the results turned out great!

Thanks to everyone and Merry Christmas, John

I have a 200/260W Weller solder gun and when I gave it some thought,
when someone spot welds a tab onto the battery, it creates a momentary
hot spot on the battery. The Weller gun can't to worse than a spot weld
as long as the time is short and proper preparation is made.

Oh, yes it can. A spot weld takes a fraction of a second, and the heat appears
over a small area.


By golly, I had no trouble at all and the results turned out great!

I hope so. I've seen connections of this sort fail * with the solder blob
simply falling off the battery.

* as do spot welds, of course

On Sat, 22 Dec 2012 06:14:53 -0800, "William Sommerwerck"
wrote:

I have a 200/260W Weller solder gun and when I gave it some thought,
when someone spot welds a tab onto the battery, it creates a momentary
hot spot on the battery. The Weller gun can't to worse than a spot weld
as long as the time is short and proper preparation is made.

Oh, yes it can. A spot weld takes a fraction of a second, and the heat appears
over a small area.

A bit more than a fraction of second. See video at:
http://www.youtube.com/watch?v=G7LKhhyokbQ
starting at 0:50. I would guess(tm) about 1/2 second for the spot
weld. I would also guess(tm) that the heat affected zone on the
battery is much larger with the high wattage Weller because of the
longer dwell time and larger thermal contact area. When I was
soldering batteries, the cell was noticably warm after soldering. When
doing the same with a CD welder, it was stone cold.

By golly, I had no trouble at all and the results turned out great!

I test my battery packs with a West Mountain Radio CBA-II.
http://www.westmountainradio.com/product_info.php?products_id=cba4
If there's a problem, it will be obvious on the graphs.

I hope so. I've seen connections of this sort fail * with the solder blob
simply falling off the battery.

Not if you sandpaper the base metal. When I solder to a battery, the
solder will wet to the edge of the sandpaper zone, but not into the
non-sandpapered area. That implies that there's some manner of
coating on the battery case that should be removed with an abrasive
before soldering.

* as do spot welds, of course

The real problems are in high current applications, where the weld
turns into a fuse. Power tools are a good example. I did a lousy job
of replacing NiMH cells in a Makita 18V driver. After about 4 hrs of
use, the pack went to open. An autopsy showed that my welds had fused
open. I went to 4 spots instead of 2 spots per terminal, and it was
fine.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"William Sommerwerck" wrote in message
...
I have a 200/260W Weller solder gun and when I gave it some thought,
when someone spot welds a tab onto the battery, it creates a momentary
hot spot on the battery. The Weller gun can't to worse than a spot weld
as long as the time is short and proper preparation is made.

Oh, yes it can. A spot weld takes a fraction of a second, and the heat
appears over a small area.


By golly, I had no trouble at all and the results turned out great!

I hope so. I've seen connections of this sort fail * with the solder blob
simply falling off the battery.

But not if it is done properly in the way that has been carefully detailed,
and by someone who can solder properly in the first place. For a number of
years, I repaired 1st and 2nd generation cordless phones, and used to make
up my own battery packs at the rate of a couple a day. These repairs were
done for a two local phone shops, and for a travelling CB and accessory
salesman who called at many shops around the country, picking up the repairs
one week, and dropping them back the next. The batteries that I was joining
by soldering were of course NiCds back then, but I never had any problems
with exploding ones, or rapid failures, and trust me, if early failures had
been an issue, the shops would soon have been throwing them back at me ...

Arfa


* as do spot welds, of course