Warning: Just a single 18650 cell has the potential to start a fire in your home / workplace. Building a battery is a very dangerous task that should only be done by an expert in electricity and electronics.
I made this thread in order to leave things crystal clear for the future.
I will update the head post with all the info required, asked, debated, requested in any other ES place.
I start with a small piece of info data I calculated as exactly as I could as deep research, I added to the data my own heat test about the max Amps that pure nickel and nickel plated steel strips stand in the right conductivity range.
Copper, nickel and steel amperage table (insulated)
The table take into account each material own resistivity, heat dissipation properties, average length for 18650 uses, ambience of work (insulated, in groups, in contact with heat generators) and measurements.
As the amount of heat released from a conductor is proportional to the square of the current (resistive heating--> Heat = amperes^2 * electrical resistance) the heat starts to increase exponentially. Beyond poor / bad values you could have melted insulators in high exterior temperatures / poor battery cooling, given the risk it suppose.
Below the optimal values the nickel stays mild and close to ambience temperature, so the efficiency is optimal under those current levels and you can measure with precision the heat generated exclusively by the cells.
As nickel and nickel plated steel are extremely difficult to difference at sight, there are an easy homemade test that could be done in order to check if you have one or another.
Take a strip sample and polish / scratch with a dremel tool or simply with a knife on a small area, and put into salty water for 12h to 24h. This is how it looks.
The upper samples are pure nickel ones, and the bottom ones are nickel plated steel. The corrosion is clearly shown. This doesn't discard the steel for welding purposes, if the strips are in good condition would be enough for batteries that will be used in dry environments.
Pure nickel and nickel plated steel corrosion test
![DSC_1394_E.jpg DSC_1394_E.jpg](https://endless-sphere.com/sphere/data/attachments/89/89652-6766c9de71f7100064353dff1fb86dbe.jpg)
You can watch a video of the test -------> http://www.youtube.com/watch?v=w40t0RxQd3Q
Where should I get authentic cells from Europe?
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
http://eu.nkon.nl/
https://www.akkuteile.de/
Where should I get authentic cells from USA?
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
http://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=18650+samsung
Where should I get authentic cells from any other place?
e.g. Samsung 26F http://aliexpress.com/item/10pcs-lo...-batteries/1405818812.html?recommendVersion=1
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
http://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=18650+samsung
Where should I get a Spot Welding machine from Europe?
Low cost classic
tested) http://aliexpress.com/item/Hand-hel...attery-Pack/594538510.html?recommendVersion=1
Low cost 788+
tested by other users) http://www.aliexpress.com/item/DHL-...er-Machine/2054203026.html?recommendVersion=1
- Review - : http://syonyk.blogspot.com.es/2015/05/overview-of-sunkko-788-welder.html
- Failure and repair of triacs - : http://syonyk.blogspot.com.es/2015/05/sunkko-788-welder-failure-and-repair.html
Recommended: JP spot welder http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865
Recommended: Sunko 709A upgraded (tested) http://www.aliexpress.com/store/product/SUNKKO-709A-High-Power-Spot-Welder-Soldering-Station-with-Universal-welding-pen/126412_1702832700.html
Make your own!: Arduino spot welder controller / solid state relay http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html#h2-universal-nbsp-arduino-solid-state-relay-dimmer
Make your own! (2): 6pence Resistance Spot Welder (brain board) https://endless-sphere.com/forums/viewtopic.php?f=31&t=81274&p=1196210#p1196210
Where should I get a Spot Welding machine from USA?
Low cost:
Recommended: http://www.ebay.com/itm/110V-Hobby-...32b5a1&pid=100011&rk=3&rkt=10&sd=151610987714
Recommended: JP spot welder http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865
Recommended: Sunko 709A upgraded (tested) http://www.aliexpress.com/store/product/SUNKKO-709A-High-Power-Spot-Welder-Soldering-Station-with-Universal-welding-pen/126412_1702832700.html
Make your own!: Arduino spot welder controller / solid state relay http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html#h2-universal-nbsp-arduino-solid-state-relay-dimmer
Make your own! (2): 6pence Resistance Spot Welder (brain board) https://endless-sphere.com/forums/viewtopic.php?f=31&t=81274&p=1196210#p1196210
Where should I get a Spot Welding machine from any other place?
Low cost: http://aliexpress.com/item/Hand-hel...attery-Pack/594538510.html?recommendVersion=1
Low cost 788+
tested by other users) http://www.aliexpress.com/item/DHL-...er-Machine/2054203026.html?recommendVersion=1
Recommended: JP spot welder http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865
Recommended: Sunko 709A upgraded (tested) http://www.aliexpress.com/store/product/SUNKKO-709A-High-Power-Spot-Welder-Soldering-Station-with-Universal-welding-pen/126412_1702832700.html
Where should I get nickel strips?
Nickel strips: (10 meters)(tested) http://aliexpress.com/item/Free-shi...ylindrical/2050759694.html?recommendVersion=1
Nickel strips: (~100 meters (1Kg)) http://aliexpress.com/store/product...e-for-battery-welding/610392_32261769234.html
Nickel strips: (~100 meters (1Kg)(tested)) http://aliexpress.com/item/FREE-SHI...Sheets-99-96-for-battery-spot/2054948107.html
Nickel plated STEEL strips (tested): http://aliexpress.com/item/100pcs-N...er-Equipment/1688446800.html?isOrigTitle=true
Where should I get a BMS?
http://liionbms.com/php/bms_options.php
Where should I get enormous battery shrink wrap?
http://stores.ebay.com/Atop-Authent...98732015&_sid=879188535&_trksid=p4634.c0.m322
http://aliexpress.com/store/group/PVC-heat-shrink-tube-battey-casing-parts/834897_252760614.html
Paralleling, serialing, balancing, BMS
http://liionbms.com/php/white_papers.php
Battery Deterioration
http://endless-sphere.com/w/index.php?title=Battery_Deterioration
https://www.youtube.com/watch?v=pxP0Cu00sZs
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
edit: moderator has received permission to add these links here
Self adhesive "fish paper" insulation sheets from ebay seller supowerbattery111
"8x Fish Adhesive Paper Electrical battery Pack Insulating"
http://www.ebay.com/itm/8x-Fish-Adh...730848?hash=item4ade741aa0:g:ZoYAAOSwEppUR2JZ
"Spot Welding Copper Strips to 18650 Battery Cells"
https://endless-sphere.com/forums/viewtopic.php?f=14&t=84680
"Brass for spot-welding 18650 parallel cell groups?"
https://endless-sphere.com/forums/viewtopic.php?f=14&t=85059
Supplier of honeycomb configuration plastic cell holders, plus 30-degree angled nickel bus-strips
https://www.aliexpress.com/item/186...battery-bracket-plastic-case/32729220653.html
I made this thread in order to leave things crystal clear for the future.
I will update the head post with all the info required, asked, debated, requested in any other ES place.
I start with a small piece of info data I calculated as exactly as I could as deep research, I added to the data my own heat test about the max Amps that pure nickel and nickel plated steel strips stand in the right conductivity range.
Copper, nickel and steel amperage table (insulated)
The table take into account each material own resistivity, heat dissipation properties, average length for 18650 uses, ambience of work (insulated, in groups, in contact with heat generators) and measurements.
As the amount of heat released from a conductor is proportional to the square of the current (resistive heating--> Heat = amperes^2 * electrical resistance) the heat starts to increase exponentially. Beyond poor / bad values you could have melted insulators in high exterior temperatures / poor battery cooling, given the risk it suppose.
Below the optimal values the nickel stays mild and close to ambience temperature, so the efficiency is optimal under those current levels and you can measure with precision the heat generated exclusively by the cells.
As nickel and nickel plated steel are extremely difficult to difference at sight, there are an easy homemade test that could be done in order to check if you have one or another.
Take a strip sample and polish / scratch with a dremel tool or simply with a knife on a small area, and put into salty water for 12h to 24h. This is how it looks.
The upper samples are pure nickel ones, and the bottom ones are nickel plated steel. The corrosion is clearly shown. This doesn't discard the steel for welding purposes, if the strips are in good condition would be enough for batteries that will be used in dry environments.
Pure nickel and nickel plated steel corrosion test
![DSC_1394_E.jpg DSC_1394_E.jpg](https://endless-sphere.com/sphere/data/attachments/89/89652-6766c9de71f7100064353dff1fb86dbe.jpg)
You can watch a video of the test -------> http://www.youtube.com/watch?v=w40t0RxQd3Q
Where should I get authentic cells from Europe?
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
http://eu.nkon.nl/
https://www.akkuteile.de/
Where should I get authentic cells from USA?
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
http://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=18650+samsung
Where should I get authentic cells from any other place?
e.g. Samsung 26F http://aliexpress.com/item/10pcs-lo...-batteries/1405818812.html?recommendVersion=1
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
http://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=18650+samsung
Where should I get a Spot Welding machine from Europe?
Low cost classic
Low cost 788+
- Review - : http://syonyk.blogspot.com.es/2015/05/overview-of-sunkko-788-welder.html
- Failure and repair of triacs - : http://syonyk.blogspot.com.es/2015/05/sunkko-788-welder-failure-and-repair.html
Recommended: JP spot welder http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865
Recommended: Sunko 709A upgraded (tested) http://www.aliexpress.com/store/product/SUNKKO-709A-High-Power-Spot-Welder-Soldering-Station-with-Universal-welding-pen/126412_1702832700.html
Make your own!: Arduino spot welder controller / solid state relay http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html#h2-universal-nbsp-arduino-solid-state-relay-dimmer
Make your own! (2): 6pence Resistance Spot Welder (brain board) https://endless-sphere.com/forums/viewtopic.php?f=31&t=81274&p=1196210#p1196210
Where should I get a Spot Welding machine from USA?
Low cost:
Recommended: http://www.ebay.com/itm/110V-Hobby-...32b5a1&pid=100011&rk=3&rkt=10&sd=151610987714
Recommended: JP spot welder http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865
Recommended: Sunko 709A upgraded (tested) http://www.aliexpress.com/store/product/SUNKKO-709A-High-Power-Spot-Welder-Soldering-Station-with-Universal-welding-pen/126412_1702832700.html
Make your own!: Arduino spot welder controller / solid state relay http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html#h2-universal-nbsp-arduino-solid-state-relay-dimmer
Make your own! (2): 6pence Resistance Spot Welder (brain board) https://endless-sphere.com/forums/viewtopic.php?f=31&t=81274&p=1196210#p1196210
Where should I get a Spot Welding machine from any other place?
Low cost: http://aliexpress.com/item/Hand-hel...attery-Pack/594538510.html?recommendVersion=1
Low cost 788+
Recommended: JP spot welder http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865
Recommended: Sunko 709A upgraded (tested) http://www.aliexpress.com/store/product/SUNKKO-709A-High-Power-Spot-Welder-Soldering-Station-with-Universal-welding-pen/126412_1702832700.html
Where should I get nickel strips?
Nickel strips: (10 meters)(tested) http://aliexpress.com/item/Free-shi...ylindrical/2050759694.html?recommendVersion=1
Nickel strips: (~100 meters (1Kg)) http://aliexpress.com/store/product...e-for-battery-welding/610392_32261769234.html
Nickel strips: (~100 meters (1Kg)(tested)) http://aliexpress.com/item/FREE-SHI...Sheets-99-96-for-battery-spot/2054948107.html
Nickel plated STEEL strips (tested): http://aliexpress.com/item/100pcs-N...er-Equipment/1688446800.html?isOrigTitle=true
Where should I get a BMS?
http://liionbms.com/php/bms_options.php
Where should I get enormous battery shrink wrap?
http://stores.ebay.com/Atop-Authent...98732015&_sid=879188535&_trksid=p4634.c0.m322
http://aliexpress.com/store/group/PVC-heat-shrink-tube-battey-casing-parts/834897_252760614.html
Paralleling, serialing, balancing, BMS
http://liionbms.com/php/white_papers.php
Battery Deterioration
http://endless-sphere.com/w/index.php?title=Battery_Deterioration
https://www.youtube.com/watch?v=pxP0Cu00sZs
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
edit: moderator has received permission to add these links here
Self adhesive "fish paper" insulation sheets from ebay seller supowerbattery111
"8x Fish Adhesive Paper Electrical battery Pack Insulating"
http://www.ebay.com/itm/8x-Fish-Adh...730848?hash=item4ade741aa0:g:ZoYAAOSwEppUR2JZ
"Spot Welding Copper Strips to 18650 Battery Cells"
https://endless-sphere.com/forums/viewtopic.php?f=14&t=84680
"Brass for spot-welding 18650 parallel cell groups?"
https://endless-sphere.com/forums/viewtopic.php?f=14&t=85059
Supplier of honeycomb configuration plastic cell holders, plus 30-degree angled nickel bus-strips
https://www.aliexpress.com/item/186...battery-bracket-plastic-case/32729220653.html