A little help with my 12s2p battery?

Hey guys! I hope your day is going great so far! I’m new to this particular forum and came here because of the recommendation from one of the guys from the electric skateboard builders forum; they said that you’re more active, and I have more chances for my questions to be answered on here!

(Just in case, here’s the specs of my build:
Battery: 12s2p using Samsung 40T
Motors: 6374 170KV
ESC: Focbox Tenka

  • remote )

So I have two questions relating to my battery:

  1. Would I be able to use 0.2mm x 8mm nickel strips, or should I stick with something else like 10 AWG wire (or maybe I should use something even…tougher)? (Photo below)

  2. I’m ultra confused about how to connect my BMS to the battery since I’m planning to bypass it for discharge as well as my BMS has a separate charging port…So I’m super confused with the whole wiring of the bms ( i do understand where to solder my balancing wires, but in terms of the others… not so much(((( Can anyone please help me out on that matter? :pleading_face: :pleading_face: :pleading_face:

(Here’s the photo of the BMS that I’m using)

So if anyone would by any chance know the answer - can you please help me out?))

P.S - Sorry in advance @b264 for tagging you here! But from the recommendations and my personal experience, you’re very well informed on this matter, and maybe you’d be able to help me? Please excuse me just in case if I’m wrong!!!

Thank you in advance!

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My apologies! (it’s 11 AWG wire,not 10 AWG)


This is a useful read. I am not an expert on battery building, bou I would at least double stack that nickel strip.

How much of range do you expect with this setup? I can’t see getting more than 15-20km with it.

@glyphiks @Acido @pjotr47 @Battery_Mooch

Just tagging some of the masters in the field you are looking help for.


It would be of great assistance for us to be able to help you if you could provide a sketch of your intended layout


id only worry about having enough nickel/wire on the series connections from pack to pack when it comes to the whole “ampacity” thing…

And if you’re gonna keep it in a flat pack like what I currently see, and you were just going to jump the series connections right off of the end I’d say use wire because that’ll be quick and easy.

12 gauge would be more than sufficient, but if you have 10 or 11 happy days. I just solder it to the center of the nickel on each group.

For your BMS:
B- goes to the battery negative
C- charge port negative
P- cap off with heat shrink.

on your battery the main positive (aside from bms wires) will have a main wire connecting your xt-90 (or 60) AND another smaller wire conneted to you charge port.

on the main battery negative (aside from bms wires) youll have another main wire connected to your xt90

always remember cell group 1 STARTS at the main negative end…i f’d this up a good few times when adding bms wires in the beginning, not the end, just extra soldering work lol

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Inb4 Brian

Welcome to the forum @N4mby_Pamby ! It’s a good place



Oh sorry, I’ve completely forgotten! This is the layout that I’m followingIMG_6855

Lots of help provided already so you probably have a good amount of knowledge now, but I would suggest checking out my latest battery video. It’s a kind of similar layout to yours and I tried to explain the balance lead process pretty well.

Let me know if it helps you out

10s4p Video

How To Build a Compact 10s4p 18650 Electric Skateboard Battery (DIY Tutorial) - YouTube


Small addon: a 2p battery will sag a lot, and the motors are kind of overkill. Also don’t make the series connections out of nickel if you plan on drawing more than 30A, because they will get hot af.

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You think it will sag? Even though it’s 21700 (4000mah) cells still gonna sag? (Maybe It will, I’m unfortunately not that experienced with battery building) :sweat_smile: :sweat_smile: :sweat_smile:

And instead of using nickel strips, do you suggest using 12 AWG wires?

Yes, wires are way better than nickel for a series connection, you can look that up in the information @b264 posted. Just make sure that you don’t solder on top of the cells, heat is VERY bad for them. Solder onto the nickel first and weld it after.

And yes, I have a 12s3p 40t pack and it sags quite a bit when accelerating, a 2p pack will be even worse. That won’t mean that it won’t work though, just the range will be limited compared to let’s say a 10s3p pack at the same amperage.