The battery builders club

If you suspect a single cell in a p group is bad, you need to tear down the group to bare single cells.

When you join X amount of cells in parallel, they essentially just become one cell.

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Yea, I think yinz all helped eliminate any other possibilities

If you mean 30Q, then that’s not really a great price. Especially if the goal is to open up and deconstruct whatever madness is inside that pack.

New, I’d likely end up with 60 for $330 or so. But I’d not likely elect to use them for a skateboard at this point with so many comparable options for less money.

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is it ok to heatshrink and then cut small holes for bms wiring?
if i do bms first then heatshrink will be almost impossible to do
i would cover the holes and exposed with with fishpaper and then glue it down to secure it

Random thought:

If you bypass discharge on the BMS, you’re not drawing large current and wouldn’t need such a heavy AWG black wire. Are there any disadvantages to using a smaller gauge with a connector so you could save space or use it to charge another pack?

Why would bypassing the BMS result in less current drawn?

I think he means use a smaller guage on the bms discharge cable. Which would also be charge - on a combined port BMS

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not quite as good as @skyart or similar but let me know what you guys think

kweld at 48.5j for welds
no welding in the middle of the negative
welds covered in fishpaper and the solder joints will be covered in fishpaper and then heat shrinked (balance leads will come afterwards)
put fishpaper in areas where leads of different voltages met
one area is a bit messy - but that is due to change of plans in the last minute in order to maximise space (still no crossing over and all good solder joints)

sorry for the not great photos

thanks a lot for looking

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I gave up on trying to understand the wiring haha but it looks good man

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yeah bit overcomplex
sadly needed to attach some 2p groups in parallel and then them all in series but for series i like to use 16awg to not heat the cells up so thats 4 wires per group
that just made things get very messy

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You used 4 cables for each S connection, why didn’t you just use 2 for each split p-group? that would’ve been a lot simpler.

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thats exactly what i did

a 12awg wire connecting p groups
then 2 16awg wires from each side of the p group to the next series group

I think I got it

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well done
your amazing
bit complex but what do you think structurally?

Thinking about the balance wires makes my head hurt, how you plan on routing those?

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No idea… sounds like paiiiin

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Wire gymnastics award goes to… Shua!

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Ah yeah I see it now. Looks like the best solution to me actually, well done. ESC’s gonna be top mounted then @Halbj613?

Well since the split packs are still in paralell by that single 12awg, you just pick one for the balance lead and thats it. Makes it actually more flexible in routing.

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You’ve come a long way. The soldering looks way better. Well done.
Be really careful with the enclosure. I worked on one of those (I think) and it cracked really easily. Could have been a faulty one.

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thank you very much

yep already tension signs building

should be an olympic sport

plan is to add fishpaper and heatshrink and then cut out tiny holes using an exacto knife for the balance leads then add fishpaper and some hot glue to secure it
felt like that is the best option here

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