The battery builders club

Yes we do. Yes we do.

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nah their 50ah ones are

they can charge at the same current as their discharge 100amps

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Given the awesome prices on the Samsung T40 21700 cells these days I am very tempted to try and squeeze a 13S2P pack inside the back of my Onewheel. However the battery tray requires a bit of creativity/experience that I am lacking at the moment.

The bottom of the tray is 190mm wide and 136mm long (this is where the inclination begins). Height is max 40mm so a honeycomb pattern is required.

The 18650 cells that I am currently running fit neatly 2 cells long in the 136mm lenght. Fits like a glove. But for 21700 cells I would either need to lengthen the board (I would rather not) or think of another configuration.

Anybody have an idea for me? BMS will be mounted externally during charging only so no need for space inside the frame.

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Does this look right? 40T cells, 10x0.15 nickel, 18xxx fish paper ring

turns out this IS the dude I ordered from off ebay! nickel passed the sparks text, salt water testing now

will report back in a few days

Any votes if I’m gonna die? The tab will be folded against the cell it’s welded too for the balance lead

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You can put fishpaper between for peace of mind. Everything else looks good

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This is the method @thisguyhere used to build my vanguard pack, seems solid so far so you should be good :ok_hand:

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Yes. Everyone dies eventually.

On another note why your fish rings so small? they should span to the edge of the cell where the negative portion is… defeats the whole purpose if it doesn’t… But they have internal rings so probably okay…

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I though using the small rings was okay? I read that here somewhere before

I can put some fish paper in the gap later, for now I need to concentrate on welding, this is literally the hardest thing ever

who told you this :joy:

20200506_135534

It is this spot that is at risk and what the extra fish paper helps against. The center of the cell around the positive terminal is hollow and doesn’t need much. But either way, there is shrink wrap and another ring underneath to protect the cells

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Will this be good? I’ll cut them to length and tack it with a strip of kapton before shrink wrap

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That solves like 99% of your problems.

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What’s the 1%?

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You didn’t line up the logos and that’s permanent.

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:scream::scream::scream:

Oh no!!

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Whelp, it’s trash now. Nice work @ZachTetra… :wink:

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You’re telling me the last 2 hours were for nothing!? I came all this way :sob:

1 of 2…gotta make the big current carriers. For a board that can’t do more than 80A max, will 12 awg be sufficient or should I go for 10 awg? (Having some issues with it, would like to avoid soldering a dozen more tabs to that stuff)

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:joy::joy::joy:

99jansens

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