Please review my battery pack so I don't make a šŸ”„

With sturdy spacers, imo not needed. But if the spacers are prone to cracking bending or meltingā€¦ I still say not needed, and get better spacers.

Mechanical stress is a real thing that can be a strong factor to this; Iā€™ve had big issues with it on my packs as well:

btw you can get neutral cure silicon amazon prime!

https://www.amazon.co.uk/gp/product/B005X685NK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

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Hereā€™s some pictures of my latest battery build- 0329191311 0329191229a 0329191316 0331192234 0329191315 0331192215a 0331191701 0401191900 0329191610 0329191616 0331191756 0401191901a 0329191610b 0331191704 0401191901

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Is there a reason why you out the fishpaper everywhere but not between the p-packs?

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There is fishpaper between the ppacks but only where terminals touch in the picture below there is fish paper where itā€™s red but not where itā€™s blue. Screenshot_2019-04-02-07-19-07~2

the blue one was my question.

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Where the blue is there are no terminals of the battery so nothing to touch and short.

but itĀ“s the place where the battery flex. because of this flex the packs can rub on ech other and damage the thin plastic cover around the cells. as you for sure know the main part of the outer cell is the negative pole. so if two packs damage there isolation next to each other over time you short your packs.

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@Andy87 Thanks for pointing that it i will definitely take that into consideration for future builds and possibly add some fish paper there on this one. however there is kapton tape over the positive cap and there are 2 layers of shrink wrap one over each of the parallel packs that fold inward a bit and covers most of the positive cap and one over the 2 parallel packs that are next to each other so the chances of it shorting that way are very slim.

Andyā€™s talking about the cell bodies rubbing together and wearing through the insulation. Cell bodies are attached to cell negative.

Heā€™s not talking about the caps/terminals.

Fish paper is more abrasion resistant than kapton or shrink wrap.

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@deucesdown I get that but the main problem would be the positve cap touching the cell body which is negitive but if the positive cap is covered it cant short on the negitive cell body.

If you have a connection from positive on one to negative on the next group in series, and the wrap wears between those groups, the cell bodies contact and essentially short positive of the first through the negative (body) of the next which is the negative of the first. Itā€™d be like shorting positive to negative on the first group directly, just via the cell bodies.

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Issue still remains I believe because the cells that are stacked ā€œfurtherā€ into the series donā€™t actually have 0V on the GND side they have all the voltage from packs before them.

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@Andy87 @deucesdown @wafflejock There is a very slight chance this will happen but just to be safe i will add fishpaper in this area on this pack and in future packs!

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This is worth reconsidering. Imagine what happens if you connect cell negatives of two touching P-groups together.

The chance may or may not be slight. The consequence is pretty serious.

Iā€™m only harping because this is the ā€œreview my packā€ thread! :slight_smile:

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@Andy87 @deucesdown @wafflejock Fishpaper has now been added between the P-groups! 0402191830

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Awesome result guys, potentially saved a burnt down esk8.

Its not obvious at first but p-groups can short each other out across the negative outside can via the nickel strip that joins the p groups. If the thin shrink wrap gets damaged from vibration etc. Shown in this diagram way above on post #65

image

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How many strips of 15x0,2 nickel would be needed for P conections, then series are done with tinned copper. 4p being up to 30a each. 3 strips?

I recommend making your packs like @taz

Or use bat pcbs

20190320_095658 20190328_192310 20190328_192901 esk8_3d_print_parts_53341586_389244764964514_5669782827451320914_n IMG_20180302_190516 IMG_20181211_214212 IMG_20181223_204324 IMG_20181224_010216 IMG_20181226_154148 IMG_20181226_181241 IMG_20181226_191718 IMG_20181226_212235 IMG_20181228_005415 kaly_23967099_154594015291245_8845322177872920576_n kaly_23967283_184690598763067_3377711132255977472_n kaly_26071448_143051296405025_252030592189726720_n kaly_26335502_889707451204571_2964203307473567744_n kaly_26396395_1545315622223599_536620953493307392_n received_203103473977359 received_10160006390310521 received_10160006654470521 20190320_095642 20190320_095650

take a look at my battery p0rn folder

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