18650 spot welding -how to- ULTIMATE REPOSITORY

[Pompecukor]

I am spot welding. As I wrote, that was from before I got my spot welder.
But thank you.

PS: one think I would be happy to know is where did you get those jointed paper gaskets?

 

[Allex]

just search ebay for 18650 insulator

 

[Solarpower]

I am spot welding. As I wrote, that was from before I got my spot welder.
But thank you.

PS: one think I would be happy to know is where did you get those jointed paper gaskets?

I bought this: https://m.fasttech.com/p/3952702

 

[jmz]

I am currently building a pack without the use of insulators.

I will be gluing and separating with kapton tape etc. to kep it rigid and avoid rubbing, but I am also interested in methods like conformal coating and even conformal coat + silicone potting to aid waterproofing and thermal management.

Does anyone here have any experience with conformal coating 18650 packs? Would it be safe to encapsulate the entire positive terminal (possible effect on venting effectiveness in the event of a short or overcharge (fortunately the Adaptto BMS seems much more reliable in this regard than others))?

 

[flippy]

conformal coating does nothing for cells in our usage. it only helps against weather corrosion and stuff. not to mention it is a total bitch to clean when you need to do work on the pack. ever tried to remove coating so you can weld/solder properly?
the coating would not stop venting. it would simply blow the coating off and possibly set it on fire.

 

[DaDo.Bzz]

Hello guys.

I know there could be somewhere here the answer, but there is lot of pages here and ballast. I have a quick question.

I have finally bought Sunkko 709A, have enough of soldering - it is very slow. I am able to weld nickel strip to battery very strong, but can not then weld nickel to nickel. It is very loose. I have tried almost all combinations (pulses, current) and don't have good result. And I have enough power, I can melt bottom nickel plate. Don't you have any experience with this?

Does anybody know how are that 4P,6P and 8P buttons meant? I can combine them, When 6P and 8P does it have 14 pulses? Also in manual is something about 2P, so when nothing is on I have 2 pulses? What about that times between pulses?

Thanks for every hint.

 

[Lash]

I have put together a shortish video (mostly of still pics with voice over) on my first battery build for the Stealth Flux Alpha. It is a Samsung 30Q 18650 battery build 18S10P using hot glue and a spot welder. It is pretty high level and basic, but hopefully is useful for beginners looking to build a high power battery. I learnt a lot from this forum so If I can give anything back that's the least I can do.

Apologies for sounding like a boring muppet if you watch it.

Cheers, Lash.

https://youtu.be/5kUqioWAR4g

 

[DVDRW]

Solder + welding combination:

80V 52AH triangle pack:

 

[Skrzypas]

I see you're (almost?) done with the project DVDRW! Nice beast. It's there a build thread?

 

[vex_zg]

Just FYI all

Bought 0.3mm strip here, and it tested ok, no rust (salt+water test, salt+vinegar+peroxide)

http://www.aliexpress.com/item/Free-shipping-18650-battery-nickel-strip-0-3mm-nickel-plate-18650-26650-cell-nickel-belt-Lithium/2050756060.html

It takes 1F charged to 18-20V to weld, around 200J

 

[Pompecukor]

Anyone have good reliable (trusted) supplier/lead for full nickel:
a.) 0.15 x 10mm
b.) 0.2 x 10mm

Ebay is full off nickel plated steel. And aliexpress is only good if you have confirmation first.
The ones I tried so far, all failed and the salt water test .
Thank you.

 

[Solarpower]

Did you look at the first post in this thread?

http://www.aliexpress.com/item/Free-shipping-18650-battery-nickel-strip-0-15mm-nickel-plate-li-ion-cell-nickel-belt-Cylindrical/2050759694.html?recommendVersion=1

 

[Pompecukor]

Did you look at the first post in this thread?

http://www.aliexpress.com/item/Free-shipping-18650-battery-nickel-strip-0-15mm-nickel-plate-li-ion-cell-nickel-belt-Cylindrical/2050759694.html?recommendVersion=1

Did you read my question? :?

(hint: 10mm width)

 

[Solarpower]

Tried asking the seller for 10mm? :?

 

[Pompecukor]

Tried asking the seller for 10mm? :?

Nope. Thought I'd as here first, in case anyone already had a "ready made" lead.

 

[irq]

Anyone have good reliable (trusted) supplier/lead for full nickel:
a.) 0.15 x 10mm
b.) 0.2 x 10mm

Ebay is full off nickel plated steel. And aliexpress is only good if you have confirmation first.
The ones I tried so far, all failed and the salt water test .
Thank you.

nkon sells pure nickel strips since a few weeks, i whould trust the dutch man way more than every chinese aliexpress reseller..

 

[Pompecukor]

Anyone have good reliable (trusted) supplier/lead for full nickel:
a.) 0.15 x 10mm
b.) 0.2 x 10mm

Ebay is full off nickel plated steel. And aliexpress is only good if you have confirmation first.
The ones I tried so far, all failed and the salt water test .
Thank you.

nkon sells pure nickel strips since a few weeks, i whould trust the dutch man way more than every chinese aliexpress reseller..

A. Out of stock.
B. Way over priced (you can trust him on this too) : 16.5 euro for a single meter. That is crazy.

 

[irq]

a) this changes nearly daily @ nkon
b) the pricing is wrong, 1m 10mm nickel -> 5€

http://eu.nkon.nl/rechargeable/18650-size/nikkel-battijersoldeerstrip-10mm.html

 

[ridethelightning]

I have put together a shortish video (mostly of still pics with voice over) on my first battery build for the Stealth Flux Alpha. It is a Samsung 30Q 18650 battery build 18S10P using hot glue and a spot welder. It is pretty high level and basic, but hopefully is useful for beginners looking to build a high power battery. I learnt a lot from this forum so If I can give anything back that's the least I can do.

Apologies for sounding like a boring muppet if you watch it.

Cheers, Lash.

https://youtu.be/5kUqioWAR4g

nice one Lash. very informative vid.
RTL

 

[Ballistrophobia]

Completely new to spot welding. This looks like a great thread, I will definitely take some time to read through this later.

I want to build a 10s4p pack using Samsung 25r's. They're rated for 20A continuous, so 4p should give me 80A continuous theoretically. I saw the amperage chart in the OP but I'm a little confused. What material, nickel or copper etc,and in what size will I need to purchase to safely spot weld my battery pack? I've seen some people on the internet suggest that Nickel strip would be enough, but that chart in the OP doesn't even come close to 80A...

Any tips or explanations any has for me would be greatly appreciated! Thanks

 

[ridethelightning]

Completely new to spot welding. This looks like a great thread, I will definitely take some time to read through this later.

I want to build a 10s4p pack using Samsung 25r's. They're rated for 20A continuous, so 4p should give me 80A continuous theoretically. I saw the amperage chart in the OP but I'm a little confused. What material, nickel or copper etc,and in what size will I need to purchase to safely spot weld my battery pack? I've seen some people on the internet suggest that Nickel strip would be enough, but that chart in the OP doesn't even come close to 80A...

Any tips or explanations any has for me would be greatly appreciated! Thanks

dont believe the specs, real world they will sag like crap at 20A and get hot, which will stuff the cells.
for 80A id be going 8p or even 10p. 10p should give you ~100A comfortably, but would def. struggle at spec 200A. need more cells in p for good performance/long lifespan.

RTL

 

[Offroader]

agreed, you can pulse them at 20A for 5 seconds, but anything long will raise the battery temp very quickly.

I find my 10 amp rated cells increase in temp very quickly if I push them at 7 amps on the street for more than 20 seconds. However, if I pulse them with off-road riding for lots of short bursts, they don't get nearly as hot.

 

[Ballistrophobia]

Thanks for the replies. I'm wanting to power a single brushless outrunner motor, it's rated for up to 80A max, but I don't expect it to pull much more than 20A or so under normal conditions ('it's very flat where I live). Even if I got 10A out of each 25r cell, I think I'll be ok with 4p.

With this new information, would you guys suggest just using nickel? Or a nickel and copper combo?

 

[Tats]

This question relates to the layout/design of a pack to minimise materials, ease of repair if required and safety. I see a lot of packs with every cell pretty much connected to every other cell in the parallel configuration and I'm wondering on the value of this vs just running the cell series connections within the pack and having external bus-bars to take the majority of the current and therefore make the parallel connections external to the pack.

e.g. Using basic Ohms law If I want say 25A current draw from the 10P battery - the bus-bars need to carry the total 25A current but each of the 10 series group of cells only draw 2.5A each. So I make 10-14s connections with nickel/whatever and on the final cell I solder or fuse this set of series cells to a busbar that can be insulated from the rest of the pack. Therefore I know that on any single piece of nickel within the pack it only has 2.5A on it. If I want to test the pack then I can isolate/check at the bus-bar each series connection easily. If I want to add additional capacity its just another 2 connections onto the bus-bar for each additional series group. To ensure a good connection to the bus-bar I drill a few holes in it and route the main leads through these and solder getting good stress-relieved connections across a large area.

Am I missing something with this approach? Note: my high school physics is very rusty....

 

[oatnet]

Am I missing something with this approach? Note: my high school physics is very rusty....

Research parallel before series vs series before parallel, there have been many discussions here.

In series before parallel, you will need a separate BMS for each series string. Even with a BMS alert, problems happen when you lose a single cell; all of the high v strings dump current into the low serial string trying to bring it up to their voltage. This can result in very high-amp transfers that exceed the capacity of your bus bar, at full pack voltage. Depending what the charge status is of the pack, this can drain the high strings below a safe LVC, or overcharge the cells in the low string at too high a c-rate or beyond safe HVC, or simply charge up a dead cell which is usually a bad idea.

Conventional wisdom here is to parallel before series - in the worst case one of the parallel strings drops voltage, and triggers the BMS, or kills the whole parallel row - but this failure happens at cell voltage, not pack voltage. A parallel row will drain itself propping up a failed cell, but cannot over volt the cell like a series-imbalance would.

-JD