Search found 178 matches

by vex_zg
Jun 30 2017 1:48am
Forum: Battery Technology
Topic: JP spot-welder, FET-switched, timed adj. pulse
Replies: 617
Views: 79712

Re: DIY spot-welder, FET-switched, processor-timed adj. puls

Hello, Can anyone tell me if it is permissible to replace the IRFB7430 fets working as flyback diodes for the JP welder with IRF2804, because the first are not available in the near store? The datasheet looks promissing, but I would like to ask you for a second opinion. Thank you in advance! what d...
by vex_zg
Jun 27 2017 2:33am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

good article covering all we know so far. the makita pack without slots was not resistance-welded I think. Notice no pressure dimples, but instead what looks like melted-pool remnants on weld joins. That would suggest microTig (pulse arc) or laser welding. Bosch pack has slots because resistance wel...
by vex_zg
Jun 22 2017 2:01am
Forum: Battery Technology
Topic: Brass for spot-welding 18650 parallel cell groups?
Replies: 70
Views: 11805

Re: Spot welding cheap yellow brass

I think if your goal is incremental improvement over existing spot welding, then brass is interesting. If your goal is to get to copper then it is not. If there was a solution to make copper work, why would anyone pursue nickel or brass? I can get copper to weld but the energy required for that wel...
by vex_zg
Jun 21 2017 2:17pm
Forum: Battery Technology
Topic: Brass for spot-welding 18650 parallel cell groups?
Replies: 70
Views: 11805

Re: Spot welding cheap yellow brass

I'm a bit disappointed actually that nobody picked up on this topic, but I'll let it stay in the archives of the internet...

anyway, I did some electrical testing, and roughly, this brass has typical resistance some 30-50% lower than pure nickel (for same cross section of course).
by vex_zg
Jun 18 2017 5:46pm
Forum: Battery Technology
Topic: Resistance Soldering Bus Strips to 18650 Cells
Replies: 116
Views: 16801

Re: Resistance soldering bus-strips onto cells

This process could probably be improved by using MOT as power source to be able to deliver more power in shorter amount of time. I've seen some DIY online where the process is done in 100s of milliseconds rather than 1000s like I'm doing. Don't know if it's better or worse, no reason not to conside...
by vex_zg
Jun 18 2017 2:57am
Forum: Battery Technology
Topic: Resistance Soldering Bus Strips to 18650 Cells
Replies: 116
Views: 16801

Re: Resistance soldering bus-strips onto cells

Interesting. You are using soldering paste instead of wire, good idea. It really solders much faster than a "normal" soldering does. Can you try forcefully ripping of the copper strip away from the solder joint? to test that it is a good joint. Sometimes when I soldered nickel strips onto ...
by vex_zg
Jun 17 2017 6:39pm
Forum: Battery Technology
Topic: Resistance Soldering Bus Strips to 18650 Cells
Replies: 116
Views: 16801

Re: Spot Welding Copper Strips to 18650 Battery Cells

I built a CD welder with weld energy measurement, I weld .2mm copper in range of 180-240J per weld, .2mm nickel takes around 80J, maybe less, per weld. I can run tests/video if more precise values are requested. 6 seconds with 50W sounds reasonable, but in my experience (using regular soldering, no...
by vex_zg
Jun 17 2017 2:49pm
Forum: Battery Technology
Topic: Resistance Soldering Bus Strips to 18650 Cells
Replies: 116
Views: 16801

Re: Spot Welding Copper Strips to 18650 Battery Cells

...but still much more Joules are to be pumped into the cell comparing to spot welding. This is not true though. Spot welding 0.2mm nickel takes considerable power. I've seen numbers around 200 Ws posted here and used that much with mixed success. I don't have a particularly good welder. My 0.2mm a...
by vex_zg
Jun 17 2017 3:24am
Forum: Battery Technology
Topic: Resistance Soldering Bus Strips to 18650 Cells
Replies: 116
Views: 16801

Re: Spot Welding Copper Strips to 18650 Battery Cells

It's not a bad idea, not sure if it's really beneficial- I just haven't looked into it. What makes you think it can take 10x more current, I'd be a bit worried about dodgy joints and fatigue related issues. Or a poor joint heating, failing and a bit of nickel coming loose. I tried it once, got a fe...
by vex_zg
Jun 10 2017 4:39pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

I think welding copper is a great idea - if you have a nice 10k pulse arc welder. If you have a spot welder, stick to nickel and optimize your design for current flow. You're missing almost nothing. 10000 $ Orion Pulse 250iEV is way too expensive. With all your experience Okashira, could we build t...
by vex_zg
Jun 09 2017 6:20pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

i tried tungsten, molybdenum, 30-70 copper tungsten. Tested for welding copper, nickel, copper-nickel. pure copper electrodes still work best for me. Tungsten/molybdenum cause more sparks and blowouts and stick much more. I have not yet tried zirconium copper (the electrodes I bought are quite big ...
by vex_zg
Jun 09 2017 5:09pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

i tried tungsten, molybdenum, 30-70 copper tungsten. Tested for welding copper, nickel, copper-nickel. pure copper electrodes still work best for me. Tungsten/molybdenum cause more sparks and blowouts and stick much more. I have not yet tried zirconium copper (the electrodes I bought are quite big i...
by vex_zg
Jun 08 2017 5:29pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

I just ordered it on aliexpress https://m.aliexpress.com/s/item/1895592146.html?spm=a2g0n.search-cache.0.0.FtWy6j They've got a range of thicknesses I was just making a joke about whether it had arrived yet having only just ordered it... Is it here yet? Ha! Lost in translation. Thanks for the link....
by vex_zg
Jun 08 2017 5:26pm
Forum: Battery Technology
Topic: Lithium Batteries Shipping Rules Discussions
Replies: 291
Views: 90703

Re: Lithium Batteries Shipping Rules Discussions

I have no specific evidence for this, but based on some posts here on ES: The vendors probably found that they couldn't sneak stuff past customs anymore without legitimate hazmat certifications, labelling correctly, etc. I suspect that in some countries customs is more thorough than others, and tho...
by vex_zg
Jun 08 2017 11:36am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

yeh .1mm is really weak. i easily welded some .2ni to .15cu on the test piece so id like to go with that- mechanically its much stronger, but ill have to be able to consistently weld it to use it. i reckon .2Cu will be a bit thick for me ive ordered a meter of both .1 & .15 so in about 3weeks i...
by vex_zg
Jun 08 2017 8:24am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 458
Views: 77678

Re: Spot Welding Copper Strips to 18650 Battery Cells

well done kdog. Was thinking (dreaming) of something similar, good to see how it looks in reality.

I experimented with .1mm and .2mm copper and really the .1mm is too weak mechanically.In my opinion. I would go with .2mm. It requires around 180Ws per weld, in my experience.
by vex_zg
Jun 08 2017 8:20am
Forum: Battery Technology
Topic: Lithium Batteries Shipping Rules Discussions
Replies: 291
Views: 90703

Re: Lithium Batteries Shipping Rules Discussions

I am in Sweden and there are no available shipping options for batteries in chinese shops (banggood, gearbest, fasttech...) Maybe it's time I switched back to coal and oil as power sources and go the full circle. I don't understand why they can't ship using boat or something, similar situation has h...
by vex_zg
May 12 2017 12:56am
Forum: Battery Technology
Topic: Simple charge voltage limiter board
Replies: 19
Views: 3077

Re: Simple charge voltage limiter board

good to know. I still haven't tested mine. I would still use a timer in addition, just as a failsafe. Don't want a fire just because a relay got stuck or something. Remember this device already is a failsafe above your charger's HVC. It's highly unlikely for both of them to fail. if you are using a...
by vex_zg
May 09 2017 6:44am
Forum: Battery Technology
Topic: Simple charge voltage limiter board
Replies: 19
Views: 3077

Re: Simple charge voltage limiter board

Hi guys. Back from holiday, received&tesed my board. It gets power from the 220V in line. The battery terminal is just for voltage measurement. 220V out line is switched on when battery voltage lies within the set minimum and maximum limits. As soon as the voltage exceeds the limit, 220V out li...
by vex_zg
May 02 2017 5:07pm
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 790
Views: 196027

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

Started my first pack. Comments and critiques welcome. Batteries are samsung 30Q. I'm building 4 modules of 5s6p, for a total of 20s6p. Each cell is capable 20A for a total pack capability of 120A. Using 0.15x7mm strips, I would need 6 strips per cell, per series connection which gets me 21A of cap...
by vex_zg
May 02 2017 5:04pm
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 790
Views: 196027

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

What do you plan on welding with that beast? Too powerful for batteries, too weak for metalworking... suprugu za kuhinju :) my wife for the kitchen board :) I wanted the ability to do copper welding at lower voltages to reduce blowouts. I can do .3mm copper now, probably even thicker, but still exp...
by vex_zg
May 01 2017 3:32pm
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 790
Views: 196027

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

quote [I started with something like that as goal but ended up building a 600ws 3F/20V CD welder myself, arduino controlled and configurable. I wanted something to weld .2mm copper and .3mm nickel, powerful reliable and customizable. Could not exactly find it so built it myself. Spent hundreds of h...
by vex_zg
Apr 29 2017 3:42pm
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 790
Views: 196027

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

Has anyone built this welder with an Arduino timer? Also a display option? http://www.avdweb.nl/tech-tips/spot-welder.html http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html click to enlarge. I started with something like that as goal but ended up building a 600ws 3F/20V ...
by vex_zg
Apr 26 2017 4:28pm
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 790
Views: 196027

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

Could I theoretically use 3 times 10awg wires and combine them to one? Because I won´t get a 1/0 wire at the moment that fast. :pancake: Is there any hardware shop with welding supply near you? They will have flexible, rubber coated, arc welding wire, it comes in number of monstrous gauges and is n...
by vex_zg
Apr 25 2017 7:59am
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 790
Views: 196027

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

flippy wrote:never, you will burn those out in 10 minutes. 4 AWG would be minimum IMHO.
I am using AWG 1/0, AWG 2/0 was too big and heavy, but 1/0 is OK.