snowSPACEboard - A learning experience fueled by a snowy winter.

Gimme my money hoe

I’ll pay you once I find out if they could do 80A @ 12s /s

Build’s fucked. I have no fucking clue what happened, btu the battery was acting weird from the start. brand new pack. Already out of balance when I built it (one group was 90mV down)

Full charge it was still a 90mV delta.

two cycles later the difference is at a whopping 200mV.

Top balance that one questionable group

Hook it up to the bathtub water heater drain tester 9000000000000000 (like a 2.5A load)

All groups held perfectly tight and balanced all the way to 3.6v. When I checked on it again at 3.4v, the BMS had cut discharge already, bad group was down below 3V, rest were at 3.4. WHAT THE FUCK MAN

I cant even afford to build a new pack right now. I have plans for this summer that take priority, this entire build was done because I had ALL of the electronics already lying around.

Nothing is mechanically wrong with the pack. I removed the BMS, desoldered the main battery leads, will fully wrap the pack with a whole lotta fishpaper and take it to recycling. fuck me man

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Where’s the bad p-group (near the ends?)

Could you remove the p-group and run the board at 11s?

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Right in the center. Pack is just welded together. Nothing I can really do.

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That’s the spirit

(Throwing the pack cos one group is bad seems like overkill, maybe try and ASSess if it can be fixed or reconfigured?)

Just had an idea- could you cut the nickel on the troublesome p-group, then run a bypass wire around?
You’d have the dead weight of the dead p-group, but at least you don’t have to toss the pack

Edit: if you wanted to be extra jank, you could drain the dead p-group down to 0v, then just solder the bypass wire across the terminals (shorting the dead p-group). you wouldn’t even need to cut nickel.

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Wouldn’t some of the current end up going through that shorted p group anyways?

Maybe? But it shouldn’t matter if the + and - are shorted via the jumper wire, because the voltage of that p-group will never not be 0v.

oufff tbh that still stresses me out. I dont think im comfortable having a group at 0v, plus i’d need a new bms and charger.

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If you do want to attempt pack surgery, dont forget the sardine can technique for removing nickel sheets.




Using sharp flush cutters is crucial for this, but it allows you to break large nickel connections without having to tear up spot welds. Nickel is sheet metal after all. It acts like sheet metal, and can easily be torn.

For anyone reading this who is not Evan: DO NOT TRY THIS. IT’S WAY TOO EASY TO FUCK UP AND SHORT A CELL.

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This is more faith than you usually put in me. I’m usually on the receiving end of these warnings

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That’s one possible reading, certainly. Another is that I dont care enough about your well-being to include you in my disclaimer :kissing_heart:

I’m concerned that you have marketing/showroom quality photos depicting this

I’m an artist. I take pride in my craft.

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Its true. This method looks very cool, I almost want to have a circumstance that would require me trying it.

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It’s not :joy: i would never say something that pretentious unironically

Found a 12s4p 30Q brick in my stash of forgotten projects (meant for an ebike)

Cells are 4 years old, never cycled, perfectly balanced at the top. I’m impressed

Also, it got a little warm while riding haha

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Sigh

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That’s how I read it