I am using two 3D-printed end caps to build 7S4P batteries for ~24V electric scooters (no, they aren’t mine lol). I plan to expand the same holder for my ebike packs and ultimately create a versions for various individual P groups.
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Why not buy the Samsung 40T or 50E for $5 each?
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I´m torn between these model 3 and molicel p42a, for a gokart battery based on the NESE modules. But I think I go with Molicel p42A, due to the higher discharge rate. I had high hope for these model 3 batteries, but seeing they only do 15amp dicharge, was a bit disappointing to me.
I guess it comes down to capacity vs. discharge rate
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P42a is only £3.25 now
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Yes I know… The price is grate on these molicel… And I´m from EU, so thats perfect for me.
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In case anyone is interested in this.
Heres a spreadsheet with tons of various batteries / pack builds all worked out for $/Wh and $/g and such
you should definitely make a copy and edit it. things on the far let re inputs, things on the right are outputs.
Units are SI so enjoy that 
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I bought the Hoover board in Hope’s of salvaging the power , charging port and cells. I’m a bit lost now because I have not seen this type of connection. I have tried to take the top off but it keep sparking. I’m sure I’m missing a step but I’ve messed with this enough that my mind spinning. Google/Youtube had a bunch of XT60 and XT90 connections. Which what I was hoping for. Any help or suggestions to point me in the right direction is greatly appreciated.
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Just a note, I was reading somewhere that the top is aluminium, so it would be impossible to spotweld
May be worth checking
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10s1p 40T double stagger, waiting for the silicone to cure (neutral 2+ of course)… tomorrow we weld!
Damn this thing is cute!
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Here is a little update on my solderless 3d printer PETG 10s4p built. It took almost 2 weeks to print 20 18650 holders. Next step is to print 45mm standoff x 40 and the positive shields x 10.
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Splicing the + charge cable and - BMS cable into the main battery leads,
they feel solid but not sure if such a lump of solder could cause issues, start again or ok?
i’ll flatten the spikes…
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The solders look a little cold dude.
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thanks, yeh, think the iron i have isn’t hot enough,
what’s the implication of cold solder here? is there more resistance and therefore heat?
Just not a good bond
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Cold. I’d expose a little more wire. Make sure they’re intertwined with some mechanical lock. Wrap with thin solid wire if you can.
Definitely need more heat as a minimum. Use the chip tip
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+1
Buy a cheap 80w iron to use for situations like this where you need maximum heat.
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will do, thanks for the advice!
@iespobolamas
Oh oh it’s mid stream. Strip more of the wires you’re T-ing into the main wire and wrap them around the main, twist once, then wrap them back around the main toward the direction they came from.
I think I said that right. It shouldn’t pull off when you tug if its right. 
You’ve gotta heat up the 12g to temp there, not just the 16g wire intersecting it. That’s why your solders on top.
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cheers,
they do feel solid and i can’t pull them apart, though i will redo them using all the advice, a hotter iron and make sure i heat the 12g.
Any concerns with tapping them “mid stream” as you put it, is there benefit to soldering the +charge and -bms wires at the battery B- and B10?