Gotcha. Yeah in that case I dont think it matters much. Someone smarter than me, please feel free to correct me 
I have not seen this to make much of a difference, but if you are worried in the resistance of the longer wire, simply use a larger guage for that wire.
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Hi Guys. First time on the forum and looking forward to learning about DIY Eskate projects! Its been on my list for a while now to build one.
Im dropping in from the efoil builders forum and had a battery-related question for my efoil build. @tinp123 recommended I check this forum out.
Im building an 18650 based 12s8p pack. Actually 2x 6s8p pack I will run in parallel. These batteries will be used for my efoil and electric fat tire cargo bike build. This will be my second battery build and am looking to make things a little more secure and capable of handling higher currents (100A). Ive ordered a kweld which will hopefully be lightyears better than my car battery + starter solenoid welder.
One thing I would really like to do with this battery is use nickel (or maybe nickel plated copper) plate instead of strips. Ive seen this done on other packs and imagine its not only easier to work with since you donāt need hundreds of individual strips, but also capable of handling higher currents without heating. Does anyone know where I can find some maybe 0.3mm thick plate or sheet? I havenāt been able to find anything in the US yet. I did see some on Aliexpress but shipping would be over a month and I was hoping to work on this over the Christmas holiday.
Thanks!
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Welcome to the esk8.news forums!
Youāll be putting those two packs in series, not parallel, correct?
What cells are you considering using? That 100A will be just your short-period max draw, not continuous (or close to it)?
I donāt have any 0.3mm nickel vendor recommendations but Iām sure someone else will have some good suggestions. Nickel plating copper doesnāt really make it any easier to spot weld so expect to use a LOT of current and be doing a lot of testing.
Using small nickel or nickel-plated steel pieces on top of the copper, to create the necessary hot spots, is an option a few have used successfully. But with just needing to handle 100A and having an 8P pack you might not need to use copper to get the overall pack efficiency you want. Wide nickel sheets and good series connections between the P-groups can go a long way.
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0.3mm is pretty thick, and you are going to need a pretty rowdy battery on your kweld to get decent welds. Most of us use 0.2mm to great effect. 30mm x 0.2mm nickel strip can be had on AliExpress, but takes a while to ship. Every once in awhile there will be a listing on ebay stateside, but not usually.
You might be able to find someone who can sell you some. I would if I didnt need all of what I have for my clientās builds.
Alternatively, check out the nickel offerings from DRI and see if any of this will work for your pack layout:
https://derelictrobot.com/search?type=product&q=Nickel
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Welcome! 
Here are some guys in USA that could help you source wide nickel, 0.2mm thickness. 0.3mm is rarely used around here.
@Skyart @kevingraehl @BenjaminF @thisguyhere @M.Hboards
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barring some super expensive industrial grade spot welder, really doubt anything diyāers are using will be effective for 0.3mm nickelā¦
i mean, it struggles at 0.2mm.
if i have high ampacity needs, i just solder on some additional copper onto the nickel strips.
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Okay, sounds fine.
Thatās different. Thatās not 12s, thatās still 6s. Unless you mean you want to run the two 6s packs in series, not parallel.
A couple things here.
First, 100A is no sweat for an 8p pack as long as the cells are halfway decent. No problem there.
Second, IMO thereās no need for either copper OR 0.3mm thick nickel for that level of current, as long as you get the design right.
A single layer of 0.2mmx30mm nickel is more than enough for 100A when you lay the P-groups out in straight lines.
Third, you will have trouble welding 0.3mm nickel, much less 0.3mm copper. And as stated above, you donāt need it.
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He mentioned e-foil, which draws a LOT of current even when just cruising. Iād say up to maybe 60-80A continuous.
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Wow thanks for all the replies guys!
yes sorry, I meant 2x 6s packs in series to make 12s. Not parallel.
Im using Samsung 30Q cells with a 15A rating. My VESC on the efoil is set to 100A max battery current to keep all the components within a pretty conservative load range (I was able to run an entire pack down, about 20 minutes, at WOT in my pool with the board strapped down. Nothing but the batteries even broke a sweat). When riding I rarely use full throttle and the average cruise current if Iām going for range is around 40-50A. 60-70 if Iām riding fairly fast.
Good to know that 0.3 might be too much to weld. I think I just read or saw on a video that the kweld can handle 0.3 pretty easily but Iāve never tried and have zero experience with it yet.
I imagine if I use plate vs. individual strips then the 0.2 would be fine. Sounds like 30mm wide would be perfect for my layout. Any idea where I could find some without waiting a month to get it from Ali?
Iāve been trying to upload a picture of my cad model but I cant post images or links on here yet (I guess because Iām a newbie?)
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Just found something on ebay from the seller higher_wire (id post a link but cant do that either yet). Seems alot easier to find now that im setting my sights on 0.2mm. The stuff from Higher_wire sounds like legit Nickel.
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DRI has .2mm nickel precut for 8P 18650 and 21700
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Itās always best to assume that any new nickel strip/sheet is in fact nickel plated steel, unless proven otherwise by your own tests.
Either the spark test, or the salt water test.
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Thanks. I checked DRI and unfortunately, it looks like the 8p strips they have are for 21700 packs and for a straight side by side setup. Im having to stagger my cells to fit them in the space I have available. Man I wish I could post a pic of my cad model!
I think i may try this ebay stuff. seller claims its the real deal nickel and they are located in US! I will spark or saltwater test before building to make sure its legit. hopefully thatās the last time those things see salty water lol.
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im using 18650 cells.
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Yeah, that layout should be just fine with 0.2*30 nickel strip.
Those final series connections (the red ones) will not work as shown there though, because the entire 100A will be concentrated into a much smaller cross section (not to mention uneven current sharing between the cells in the first and last p-groups.)
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Thanks for the input. im planning on flattening out a piece of 10-12awg wire and soldering along the entire length of the red tabs. These two wires would merge into on 8awg positive lead. I saw a picture were someone took a 30mm strip and folded it in half (hot dog style). That way they could solder the wire to the strip first, then spot weld the other half to the cells and then fold the half with the wire over top of the cellsā¦ Not sure if that makes sense. wish i could find the picture again.
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