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.
"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?
"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
"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 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."
Are dead alkaline batteries good to practice on?
Are dead alkaline batteries good to practice on?
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.
"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 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 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."
On 9/7/2023 4:48 AM, Jim Wilkins wrote:
"Bob La Londe" wrote in message news:udaske$2liat$1@dont-email.me...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.
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?
Never tried spot welding cells myself.
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.
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.
Maybe... but this has been going on for years now and bought from<snip>
different stores. Some of the batteries came with product. I suspect
it started when manufacturing was moved to China...
"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.
Have a bucket of sand handy to drop batteries into, and be prepared to
rush batteries outside.
Have a bucket of sand handy to drop batteries into, and be prepared to
rush batteries outside.
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