Does anyone have useful experience with spotwelding nickel strips to Li
batteries with an AC spotwelder as the power source?
For equipment I have a Harbor Freight 240V portable spotwelder and a 240V
Variac to reduce its input voltage and power, a battery spotwelding
handpiece with a switch that closes when both electrodes have been pressed
against the nickel strip, and a 120/240V 40A timer I built that adjusts from
50mS to 1 or 3 Seconds.

Obviously I'll have to experiment to find a good setting, but this rig has
the power to destroy in a blinding flash if set incorrectly so I'd like to
find a reasonably safe starting point. The online advice is to try a 12V car
battery.

Thx, jsw

On Wed, 6 Sep 2023 07:29:44 -0400, "Jim Wilkins"
<muratlanne@gmail.com> wrote:

>Does anyone have useful experience with spotwelding nickel strips to Li
>batteries with an AC spotwelder as the power source?
>For equipment I have a Harbor Freight 240V portable spotwelder and a 240V
>Variac to reduce its input voltage and power, a battery spotwelding
>handpiece with a switch that closes when both electrodes have been pressed
>against the nickel strip, and a 120/240V 40A timer I built that adjusts from
>50mS to 1 or 3 Seconds.
>
>Obviously I'll have to experiment to find a good setting, but this rig has
>the power to destroy in a blinding flash if set incorrectly so I'd like to
>find a reasonably safe starting point. The online advice is to try a 12V car
>battery.

I have one of those handheld spot welders from HF, and I do run it
from a Variac to tone it down. I use 0.002" stainless steel foil as
the test case, and can easily find a variac setting that neatly welds
the foil sheets together without burning a hole. Having done that,
one can then try welding a battery tab on. Will likely take a higher
setting than for the foil, but the variac setting isn't that critical.

The 12-volt battery has the short-circuit current it has, which cannot
be changed unless one has a carbon-pile power resistor handy.

Joe Gwinn

"Joe Gwinn" wrote in message
news:cd0hfilu5afn4lltoj6i9l92v8s3p72je9@4ax.com...

I have one of those handheld spot welders from HF, and I do run it
from a Variac to tone it down. I use 0.002" stainless steel foil as
the test case, and can easily find a variac setting that neatly welds
the foil sheets together without burning a hole. Having done that,
one can then try welding a battery tab on. Will likely take a higher
setting than for the foil, but the variac setting isn't that critical.

Joe Gwinn

----------------------
Thanks.
Have you encountered any settings or combinations you consider dangerous?

On Wed, 6 Sep 2023 12:15:49 -0400, "Jim Wilkins"
<muratlanne@gmail.com> wrote:

>"Joe Gwinn" wrote in message
>news:cd0hfilu5afn4lltoj6i9l92v8s3p72je9@4ax.com...
>
>I have one of those handheld spot welders from HF, and I do run it
>from a Variac to tone it down. I use 0.002" stainless steel foil as
>the test case, and can easily find a variac setting that neatly welds
>the foil sheets together without burning a hole. Having done that,
>one can then try welding a battery tab on. Will likely take a higher
>setting than for the foil, but the variac setting isn't that critical.
>
>Joe Gwinn
>
>----------------------
>Thanks.
>Have you encountered any settings or combinations you consider dangerous?

Only running too hot. So start at zero on the variac, and work your
way up.

You may need some kind of fixture to hold the battery and tab, unless
you have three hands.

Joe Gwinn

"Joe Gwinn" wrote in message
news:5iphfi5flicoq5hi6i2h0f36i68gve2pcn@4ax.com...

On Wed, 6 Sep 2023 12:15:49 -0400, "Jim Wilkins"
<muratlanne@gmail.com> wrote:

>"Joe Gwinn" wrote in message
>news:cd0hfilu5afn4lltoj6i9l92v8s3p72je9@4ax.com...
>
>I have one of those handheld spot welders from HF, and I do run it
>from a Variac to tone it down. I use 0.002" stainless steel foil as
>the test case, and can easily find a variac setting that neatly welds
>the foil sheets together without burning a hole. Having done that,
>one can then try welding a battery tab on. Will likely take a higher
>setting than for the foil, but the variac setting isn't that critical.
>
>Joe Gwinn
>
>----------------------
>Thanks.
>Have you encountered any settings or combinations you consider dangerous?

Only running too hot. So start at zero on the variac, and work your
way up.

You may need some kind of fixture to hold the battery and tab, unless
you have three hands.

Joe Gwinn
------------------------
I have a benchtop electronic assembly press that could hold the fixture and
handpiece.

The handpiece pins compress a ways before closing the switch, and I can wire
it in series with the foot switch to trigger the timer only when both are
closed.
https://www.amazon.com/gp/product/B08R6Y9DNM/ref=ask_ql_qh_dp_hza

On 9/6/2023 2:45 PM, Jim Wilkins wrote:
> "Joe Gwinn"  wrote in message
> news:5iphfi5flicoq5hi6i2h0f36i68gve2pcn@4ax.com...
>
> On Wed, 6 Sep 2023 12:15:49 -0400, "Jim Wilkins"
> <muratlanne@gmail.com> wrote:
>
>> "Joe Gwinn"  wrote in message
>> news:cd0hfilu5afn4lltoj6i9l92v8s3p72je9@4ax.com...
>>
>> I have one of those handheld spot welders from HF, and I do run it
>> from a Variac to tone it down.  I use 0.002" stainless steel foil as
>> the test case, and can easily find a variac setting that neatly welds
>> the foil sheets together without burning a hole.  Having done that,
>> one can then try welding a battery tab on.  Will likely take a higher
>> setting than for the foil, but the variac setting isn't that critical.
>>
>> Joe Gwinn
>>
>> ----------------------
>> Thanks.
>> Have you encountered any settings or combinations you consider dangerous?
>
> Only running too hot.  So start at zero on the variac, and work your
> way up.
>
> You may need some kind of fixture to hold the battery and tab, unless
> you have three hands.
>
> Joe Gwinn
> ------------------------
> I have a benchtop electronic assembly press that could hold the fixture
> and handpiece.
>
> The handpiece pins compress a ways before closing the switch, and I can
> wire it in series with the foot switch to trigger the timer only when
> both are closed.
> https://www.amazon.com/gp/product/B08R6Y9DNM/ref=ask_ql_qh_dp_hza
>

If you are making a generic powerpack / battery its no big deal. Your
BMS choice will determine how it works. If you are rebuilding power
tool battery packs some of them now have anti repair serialize
components. You may be able to replace cells, but nothing else. Linus
Tech Tips can sometimes be a good resource for this sort of thing, but I
think they mostly produce information on YouTube.

Have a bucket of sand handy to drop batteries into, and be prepared to
rush batteries outside. A lot of first timers seem to have issue until
they get the "knack."

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

On 9/6/23 5:57 PM, Bob La Londe wrote:
> On 9/6/2023 2:45 PM, Jim Wilkins wrote:
>> "Joe Gwinn"  wrote in message
>> news:5iphfi5flicoq5hi6i2h0f36i68gve2pcn@4ax.com...
>>
>> On Wed, 6 Sep 2023 12:15:49 -0400, "Jim Wilkins"
>> <muratlanne@gmail.com> wrote:
>>
>>> "Joe Gwinn"  wrote in message
>>> news:cd0hfilu5afn4lltoj6i9l92v8s3p72je9@4ax.com...
>>>
>>> I have one of those handheld spot welders from HF, and I do run it
>>> from a Variac to tone it down.  I use 0.002" stainless steel foil as
>>> the test case, and can easily find a variac setting that neatly welds
>>> the foil sheets together without burning a hole.  Having done that,
>>> one can then try welding a battery tab on.  Will likely take a higher
>>> setting than for the foil, but the variac setting isn't that critical.
>>>
>>> Joe Gwinn
>>>
>>> ----------------------
>>> Thanks.
>>> Have you encountered any settings or combinations you consider
>>> dangerous?
>>
>> Only running too hot.  So start at zero on the variac, and work your
>> way up.
>>
>> You may need some kind of fixture to hold the battery and tab, unless
>> you have three hands.
>>
>> Joe Gwinn
>> ------------------------
>> I have a benchtop electronic assembly press that could hold the
>> fixture and handpiece.
>>
>> The handpiece pins compress a ways before closing the switch, and I
>> can wire it in series with the foot switch to trigger the timer only
>> when both are closed.
>> https://www.amazon.com/gp/product/B08R6Y9DNM/ref=ask_ql_qh_dp_hza
>>
>
>
> If you are making a generic powerpack / battery its no big deal.  Your
> BMS choice will determine how it works.  If you are rebuilding power
> tool battery packs some of them now have anti repair serialize
> components.  You may be able to replace cells, but nothing else.  Linus
> Tech Tips can sometimes be a good resource for this sort of thing, but I
> think they mostly produce information on YouTube.
>
> Have a bucket of sand handy to drop batteries into, and be prepared to
> rush batteries outside.  A lot of first timers seem to have issue until
> they get the "knack."

Linus Tech Tips also has a forum with quite an eclectic collection of
topics. I searched for "battery spot welder" and found a few hits, this
one has a little data in one post
https://linustechtips.com/topic/1317889-spot-welder-question/#comment-14581760
:

"Anyway i bought the kWeld and it works amazing, i hooked it up to a
cheep car battery from AutoZone ($70) and i was off welding all my
batteries without issue. I was welding at about 65J each hit and did 6
spots on each battery and the welds are super strong and hard to tear
apart using .2 nickel strips."

Didn't browse the other threads, and there are probably better search
terms. Enjoy.

I used to replace mass spectrometer filaments by spotwelding
0.030"x0.001" rhenium ribbon to 316SS posts, using a capacitive
discharge spot welder. As I recall it needed about 100-150J but rhenium
has a much higher melting point than nickel. Too little and no-stickum,
too much (over 200J?) and there was just a hole :-(.

--
Regards,
Carl

"Carl" wrote in message news:3K9KM.307241$f7Ub.303462@fx47.iad...

I used to replace mass spectrometer filaments by spotwelding
0.030"x0.001" rhenium ribbon to 316SS posts, using a capacitive
discharge spot welder. As I recall it needed about 100-150J but rhenium
has a much higher melting point than nickel. Too little and no-stickum,
too much (over 200J?) and there was just a hole :-(.
Regards,
Carl

----------------------
Thanks.

You fixed chem lab equipment? I used it but never learned repair.

That's a lot of energy. I built a battery fault simulator to the specs of
[big US car company] that generated Load Dump pulses of close to that
[nondisclosure agreement]. After a few pulses it overheated and fried their
protection device, which may have been the reason for side terminal
batteries.

A Load Dump occurs when the battery connection is corroded and opens from
vibration while the rotor current is at max. Then the alternator behaves
like an ignition or Tesla coil, converting the stored energy into output
voltage that rises until something absorbs the current.
https://m.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_suppression_of_transients_in_an_automotive_environment_application_note.pdf
"The surge energy rating needed for the suppressor can be found by taking
the integral of the surge power over time, resulting in approximately 85J."
Or 0.5LI^2, 0.5CV^2.

After moving into aerospace I made an electrical and optical fixture for
MOPA laser diodes with 0.001" x 0.005: Au ribbon bonded to the pads and free
on the other end. That stuff is NOT easy to work with. The signal input
needed to be a GHz transmission line with a custom series matching resistor
which I made into a connector by arranging a plastic tab to bear down on the
Au plated end pad, and slipped the ribbons under it. The power section
ribbons were spliced with silver epoxy. That was the most demanding delicate
job I ever had.

"Bob La Londe" wrote in message news:udaske$2liat$1@dont-email.me...

Have a bucket of sand handy to drop batteries into, and be prepared to
rush batteries outside. A lot of first timers seem to have issue until
they get the "knack."
Bob La Londe

-------------------

Thanks, good precaution, I can use the stove hot ash bucket. I was planning
to work outdoors anyway, to avoid smoke in the house. Are dead alkaline
batteries good to practice on?

On Thu, 7 Sep 2023 07:48:24 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:

<snip>
>Are dead alkaline batteries good to practice on?

I haven't seen a dead alkaline battery in years. They leak long before
going dead. All the big brands. Sometimes they leak before the store
can even sell them🙁

--
Leon Fisk
Grand Rapids MI

"Leon Fisk" wrote in message news:udcoqk$318ur$1@dont-email.me...

On Thu, 7 Sep 2023 07:48:24 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:

<snip>
>Are dead alkaline batteries good to practice on?

I haven't seen a dead alkaline battery in years. They leak long before
going dead. All the big brands. Sometimes they leak before the store
can even sell them🙁

Leon Fisk

------------------

Hmmm, I haven't seen leakage from primary cells in years. The Rayovac
Renewals I bought in the 90's and still use sometimes leak a bit but haven't
corroded the contacts, I wash and keep using them.

I bought a used Moultrie trail cam with a badly rusted battery contact
spring that I repaired by soldering a nickel foil strip to the undamaged
base.

On Thu, 7 Sep 2023 12:24:42 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:

<snip>
>Hmmm, I haven't seen leakage from primary cells in years. The Rayovac
>Renewals I bought in the 90's and still use sometimes leak a bit but haven't
>corroded the contacts, I wash and keep using them.
>
>I bought a used Moultrie trail cam with a badly rusted battery contact
>spring that I repaired by soldering a nickel foil strip to the undamaged
>base.

I've started using Energizer Lithium AA and AAA's. Expensive as all get
out but will be worth it if they don't leak. It's only been a year or
so, not long enough to learn much yet.

I've not had any leakage problem with rechargeables either but they
aren't really the best choice for a lot of devices...

--
Leon Fisk
Grand Rapids MI

On Thu, 7 Sep 2023 12:24:42 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:

<snip>
>I bought a used Moultrie trail cam with a badly rusted battery contact
>spring that I repaired by soldering a nickel foil strip to the undamaged
>base.

Posted some pictures I took here (expire in 31 days):

https://postimg.cc/gallery/Q51f76Z

The thermometer was a real pain to clean up. Has an outside probe
cord. Decided it would be easiest to do it in place.

Battery dates were all good yet. I'd take a peek at the batteries
off/on but you'd have to do it almost daily I think. All items worked
till the leakage caused a problem. The TV remote and Timer are used
daily🤷

--
Leon Fisk
Grand Rapids MI

On 9/7/2023 4:48 AM, Jim Wilkins wrote:
> "Bob La Londe"  wrote in message news:udaske$2liat$1@dont-email.me...
>
> Have a bucket of sand handy to drop batteries into, and be prepared to
> rush batteries outside.  A lot of first timers seem to have issue until
> they get the "knack."
> Bob La Londe
>
> -------------------
>
> Thanks, good precaution, I can use the stove hot ash bucket. I was
> planning to work outdoors anyway, to avoid smoke in the house. Are dead
> alkaline batteries good to practice on?
>
I have not a clue. I've never done it. I did once spent an afternoon
trying to solder (not lithium) cells with about an 80% failure rate.
Never tried spot welding cells myself.

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

On 9/6/2023 6:31 PM, Carl wrote:
> On 9/6/23 5:57 PM, Bob La Londe wrote:
>> On 9/6/2023 2:45 PM, Jim Wilkins wrote:
>>> "Joe Gwinn"  wrote in message
>>> news:5iphfi5flicoq5hi6i2h0f36i68gve2pcn@4ax.com...
>>>
>>> On Wed, 6 Sep 2023 12:15:49 -0400, "Jim Wilkins"
>>> <muratlanne@gmail.com> wrote:
>>>
>>>> "Joe Gwinn"  wrote in message
>>>> news:cd0hfilu5afn4lltoj6i9l92v8s3p72je9@4ax.com...
>>>>
>>>> I have one of those handheld spot welders from HF, and I do run it
>>>> from a Variac to tone it down.  I use 0.002" stainless steel foil as
>>>> the test case, and can easily find a variac setting that neatly welds
>>>> the foil sheets together without burning a hole.  Having done that,
>>>> one can then try welding a battery tab on.  Will likely take a higher
>>>> setting than for the foil, but the variac setting isn't that critical.
>>>>
>>>> Joe Gwinn
>>>>
>>>> ----------------------
>>>> Thanks.
>>>> Have you encountered any settings or combinations you consider
>>>> dangerous?
>>>
>>> Only running too hot.  So start at zero on the variac, and work your
>>> way up.
>>>
>>> You may need some kind of fixture to hold the battery and tab, unless
>>> you have three hands.
>>>
>>> Joe Gwinn
>>> ------------------------
>>> I have a benchtop electronic assembly press that could hold the
>>> fixture and handpiece.
>>>
>>> The handpiece pins compress a ways before closing the switch, and I
>>> can wire it in series with the foot switch to trigger the timer only
>>> when both are closed.
>>> https://www.amazon.com/gp/product/B08R6Y9DNM/ref=ask_ql_qh_dp_hza
>>>
>>
>>
>> If you are making a generic powerpack / battery its no big deal.  Your
>> BMS choice will determine how it works.  If you are rebuilding power
>> tool battery packs some of them now have anti repair serialize
>> components.  You may be able to replace cells, but nothing else.
>> Linus Tech Tips can sometimes be a good resource for this sort of
>> thing, but I think they mostly produce information on YouTube.
>>
>> Have a bucket of sand handy to drop batteries into, and be prepared to
>> rush batteries outside.  A lot of first timers seem to have issue
>> until they get the "knack."
>
> Linus Tech Tips also has a forum with quite an eclectic collection of
> topics.  I searched for "battery spot welder" and found a few hits, this
> one has a little data in one post
> https://linustechtips.com/topic/1317889-spot-welder-question/#comment-14581760 :
>
> "Anyway i bought the kWeld and it works amazing, i hooked it up to a
> cheep car battery from AutoZone ($70) and i was off welding all my
> batteries without issue. I was welding at about 65J each hit and did 6
> spots on each battery and the welds are super strong and hard to tear
> apart using .2 nickel strips."

Interwetingly I watched one of the first if not the first video of the
Linus Tech guys trying to make a power pack with lithium cells. They
sent may of the tiny soldiers to the lithium cemetery.

Maybe it was their first video on using reclaimed cells. I forget.
After a while it all runs together.

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

On 9/7/2023 12:45 PM, Bob La Londe wrote:
> On 9/7/2023 4:48 AM, Jim Wilkins wrote:
>> "Bob La Londe"  wrote in message news:udaske$2liat$1@dont-email.me...
>>
>> Have a bucket of sand handy to drop batteries into, and be prepared to
>> rush batteries outside.  A lot of first timers seem to have issue until
>> they get the "knack."
>> Bob La Londe
>>
>> -------------------
>>
>> Thanks, good precaution, I can use the stove hot ash bucket. I was
>> planning to work outdoors anyway, to avoid smoke in the house. Are
>> dead alkaline batteries good to practice on?
>>
> I have not a clue.  I've never done it.  I did once spent an afternoon
> trying to solder (not lithium) cells with about an 80% failure rate.
> Never tried spot welding cells myself.
>

I have a couple or few battery packs for my 18V DeWalt drills/etc
that I think have bad cells . I also have a TIG welder with a "spot"
setting - though I think that is more accurately a "tack" setting . I
also have an HF stud welder (body work) , and I think one of those might
work to re weld battery tie strips in my battery packs .
But which one ? The TIG is adjustable for both time and amperage ,
the stud welder is what it is .
<stir-stir-stir>
--
Snag
Men don't protect women because they're weak .
We protect them because they're important .

"Leon Fisk" wrote in message news:udd26n$32hnm$1@dont-email.me...

On Thu, 7 Sep 2023 12:24:42 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:

<snip>
>I bought a used Moultrie trail cam with a badly rusted battery contact
>spring that I repaired by soldering a nickel foil strip to the undamaged
>base.

Posted some pictures I took here (expire in 31 days):

https://postimg.cc/gallery/Q51f76Z

The thermometer was a real pain to clean up. Has an outside probe
cord. Decided it would be easiest to do it in place.

Battery dates were all good yet. I'd take a peek at the batteries
off/on but you'd have to do it almost daily I think. All items worked
till the leakage caused a problem. The TV remote and Timer are used
daily🤷

Leon Fisk
Grand Rapids MI

------------------------------------
Your climate is similar to ours in New England.
I wonder if your local stores received a batch that had been stored in a
very hot warehouse somewhere else. When I was testing field returns I
noticed short lifetimes of Lithiums from Arizona ambulances. The batteries
internally logged their charge level and temperature histories.

On Thu, 7 Sep 2023 17:27:24 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:

<snip>
>Your climate is similar to ours in New England.
>I wonder if your local stores received a batch that had been stored in a
>very hot warehouse somewhere else. When I was testing field returns I
>noticed short lifetimes of Lithiums from Arizona ambulances. The batteries
>internally logged their charge level and temperature histories.

Maybe... but this has been going on for years now and bought from
different stores. Some of the batteries came with product. I suspect
it started when manufacturing was moved to China...

A very different "horse" but I've had really good luck with Eneloop
rechargeables. They have "Made in Japan" on them🤷

--
Leon Fisk
Grand Rapids MI

"Bob La Londe" wrote in message news:udd2bh$32onq$4@dont-email.me...

Interwetingly I watched one of the first if not the first video of the
Linus Tech guys trying to make a power pack with lithium cells. They
sent may of the tiny soldiers to the lithium cemetery.
Bob La Londe

-------------------------

I bought most of a case of cell phone chargers that were nearing or at low
voltage expiration, where the BMS shuts them off. By connecting a lab supply
directly to the tab strips I brought almost all of them back to full charge,
and top them off twice a year. They are all 18650s I can use to rebuild
laptop batteries, if I can open them without irreparable damage. The
immediate project is tabs on coin cells for the CMOS in laptops, though I
bought the spotwelder for joining sheet metal and wire.

"Snag" wrote in message news:uddbep$3452q$1@dont-email.me...

I have a couple or few battery packs for my 18V DeWalt drills/etc
that I think have bad cells . I also have a TIG welder with a "spot"
setting - though I think that is more accurately a "tack" setting . I
also have an HF stud welder (body work) , and I think one of those might
work to re weld battery tie strips in my battery packs .
But which one ? The TIG is adjustable for both time and amperage ,
the stud welder is what it is .
<stir-stir-stir>
Snag

----------------------
The few numerical specs I found for nickel tab spot welders ran around 1000A
at 8-12V. Do you have a Variac to reduce the power of the stud welder? Their
current rating, mainly for the carbon brush, is for continuous use because
they are resistive and heat up and the catalogs say they can withstand 5
times or more current briefly and intermittently.

I've read that the resistance is necessary to reduce current between
adjacent windings when the brush bridges them, the same as for DC motors. I
think a few tenths of a volt drop at full load is enough. The brush
composition has a voltage and resistance rating accordingly.

Didn't see a mention of Unitek. It is (or was) a company that
made precision capacitor discharge welders for smallish work.
They used to be common tools in physics labs for welding wires
and foils made of refractory metals. I think they were probably
developed to assemble vacuum tube internals.

Don't know if you could still find one, but it seems to me
it'd be close to ideal for welding directly to battery cells.

HTH,

bob prohaska

"bob prohaska" wrote in message news:udds4t$3624s$2@dont-email.me...

Didn't see a mention of Unitek. It is (or was) a company that
made precision capacitor discharge welders for smallish work.
They used to be common tools in physics labs for welding wires
and foils made of refractory metals. I think they were probably
developed to assemble vacuum tube internals.

Don't know if you could still find one, but it seems to me
it'd be close to ideal for welding directly to battery cells.

HTH,

bob prohaska

-------------------------
Battery tab spotwelders start at around $30 on Amazon.

I will build something I might be able to buy for the engineering and
troubleshooting experience. That's part of how I advanced from assembler to
machine designer, and technician to circuit designer.

On Thu, 7 Sep 2023 17:48:52 -0400
Leon Fisk <lfiskgr@gmail.invalid> wrote:

>Maybe... but this has been going on for years now and bought from
>different stores. Some of the batteries came with product. I suspect
>it started when manufacturing was moved to China...
<snip>

Took a look at the two remaining Energizer AAA batteries from the HF
Flash/Utility light and they have "Made in USA" on them. The Duracell's
of late have "Made in China". Some older Duracell I still had on the
bench were "Made in USA". So not that simple of an explanation...

--
Leon Fisk
Grand Rapids MI

On Fri, 8 Sep 2023 06:38:40 -0400, "Jim Wilkins"
<muratlanne@gmail.com> wrote:

>"bob prohaska" wrote in message news:udds4t$3624s$2@dont-email.me...
>
>Didn't see a mention of Unitek. It is (or was) a company that
>made precision capacitor discharge welders for smallish work.
>They used to be common tools in physics labs for welding wires
>and foils made of refractory metals. I think they were probably
>developed to assemble vacuum tube internals.
>
>Don't know if you could still find one, but it seems to me
>it'd be close to ideal for welding directly to battery cells.
>
>HTH,
>
>bob prohaska
>
>-------------------------
>Battery tab spotwelders start at around $30 on Amazon.
>
>I will build something I might be able to buy for the engineering and
>troubleshooting experience. That's part of how I advanced from assembler to
>machine designer, and technician to circuit designer.

Jewelers also use capacitor discharge welders.

Joe Gwinn

Bob La Londe <none@none.com99> writes:

>Have a bucket of sand handy to drop batteries into, and be prepared to
>rush batteries outside.

A *steel* bucket....
A famous DC hardware store had a outdoor sand ashtray bucket
that was plastic.

The store burned down.....
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