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LifeP04 blue wrap

Norm01

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Joined
Feb 9, 2021
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Hi all, I am building a LifeP04, 12v, 302A battery set for my RV to replace two AGM’s. I purchased grade A CATL cells. I also purchased 8020 aluminum extrusion with the idea of building an exoskeleton around the batteries. I didn’t realize that the aluminum case on these batteries is positive. Obviously the batteries need to be well isolated from the aluminum frame and steel box below. I was going to 3M tape these together but now believe I will us HPDE between them. I’m also thinking it would be better to simply build a Woden box for them. Any thoughts and a question, does anyone know what would happen if the blue film rubes off between 2 batteries and the positives touch. Thanks.
 
I used plastic file folder material to separate my cells in case there was any leakage. I have a 3P16S pack and did not isolate the goups of three cells since the bus bars were attaching each group. I did isolate each group of three from the next group because they were in series.
I use the term leakage because I don't believe the aluminum has the same potential as the terminal top but it could be enough to cause imbalance or other inconsistancies.
 
I can’t take credit for this since another member suggested it many months ago but I use these plastic cutting mats between all of my cells. Affordable Dollar Store prodcut:

Cooking Concepts Flexible Chopping Mats, 2-ct. Packs​

SKU: 145661

I used a paper cutter to trim them down to size and put the plastic sheet between each battery cell. This gives you excellent cell to cell isolation. I then used kapton tape to secure the cells all together to make up the battery. Zoom in on the battery pic to see the plastic between the cells.

Lastly re-coat/tape over any holes/bare spots in the blue covering on the cells to be safe. I have not tested this myself but others state that the metal casing is conducting.
 

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I'd wrap the cells in kapton tape.
Now that would be pricey.
I can’t take credit for this since another member suggested it many months ago but I use these plastic cutting mats between all of my cells. Affordable Dollar Store prodcut:
Not saying its better than Woody’s suggestion, but I used this cutting board:
That is inexpesive and I could cut out two batteries per sheet. Comes with 15 pieces.

On one of two batteries,I also used this neoprene:
That pesky math required me to get three rolls of this to do two 8S battery packs with 280 ah cells.

When this case is done. Please post picks. I wanted to do something like this, but went for plywood instead.
 
OP doesn't come back to his own thread (like so many others), and members with 2k posts come up with bullshit. Why am I even bothering. I'll just stick to Will's videos.
 
OP doesn't come back to his own thread (like so many others), and members with 2k posts come up with bullshit. Why am I even bothering. I'll just stick to Will's videos.
I’m still waiting to see how much it’ll cost.
 
I'd wrap the cells in kapton tape.
nice, that material is quite robust in high temperatures, great idea.

kapton, also called polyimide is used in all sorts of builds.

1mil is pretty paper thin, and wrinkles easily with my clumsy application
2mil much easier to apply and feels much more robust to me. would recommend 2mil if can find.


1641344280068.png
1641344336819.png

207.2mm tall (8.1 inch tall, need 8.1 inches width total of tape)
173.93mm wide
71.65mm deep

to wrap one cell around the sides, this requires at minimum 4 faces, preferably 5 so there's no gap at the start/end.

counting distance around the cell...
left side + front + right side + back + left side
71.65mm + 173.93mm + 71.65mm + 173.93mm + 71.65mm = 388.88 mm length of tape per cell.

freedom time, 15.31 inches of tape per cell;

1 yard is 36 inches. 1 inch is 25.4mm. 1 yard is 914.4mm.

this beautiful roll of polyimide/kapton tape is 36 yards, or 1296 inches or 32918.4 mm.
1641344837965.png
https://www.amazon.com/Polyimide-Tape-Temperature-Electrical-Application/dp/B07HB9XKSD/
1641344850520.png

since that roll is 3inches wide and the cell is 207.2mm or 8.1 inches tall, we will need at least 8.1 inch / 3 inch = 2.7 and round up to 3 parallel runs of tape around the cell. so we need 3x the length of tape to cover the entire height of the cell.

recap!

15.31 inches of tape per cell
1296 inches of tape per 36yard roll.

1296 / 15.31 = 84.6 loops around the cell
84.6 loops around the cell / 3 strips wide = 28.2 cells worth of tape

28.2 cells worth of tape in the 17.95 usd roll of 1mil kapton/polyimide.

17.95 usd / 28 cells = 0.64 usd per cell for tape

64 cents per cell to wrap with polyimide/kapton seems rather affordable to me in my humble opinion.

just another option.
 
Hi all, I am building a LifeP04, 12v, 302A battery set for my RV to replace two AGM’s. I purchased grade A CATL cells. I also purchased 8020 aluminum extrusion with the idea of building an exoskeleton around the batteries. I didn’t realize that the aluminum case on these batteries is positive. Obviously the batteries need to be well isolated from the aluminum frame and steel box below. I was going to 3M tape these together but now believe I will us HPDE between them. I’m also thinking it would be better to simply build a Woden box for them. Any thoughts and a question, does anyone know what would happen if the blue film rubes off between 2 batteries and the positives touch. Thanks.
hi,

the existing blue wrap is vinyl i think. very easy to nick through and conduct. on my 302Ah CATL cells, there's already a few tiny spots that are gouged because i gently tapped it against an adjacent cell.

i got 8" wide 1mil kapton roll of tape and plan on wrapping each cell at least once around, maybe twice around, to give it a much more solid skin.

there was one forum member who posted problems with directly clamping them together and current flowing through unexpected areas. if i find the thread, will link.. in general it's good to add some sort of extra electrical isolation between the aluminum shell of the cell and any metal around it.

hope this helps! HDPE, kapton, polyimide tape, cooking mats, these all seem like non-problematic materials to me for this use.
 
1641346710598.jpeg
added picture of 302Ah CATL cell alongside roll of 8 inch wide 1mil thick kapton/polyimide tape
 
nice, that material is quite robust in high temperatures, great idea.

kapton, also called polyimide is used in all sorts of builds.

1mil is pretty paper thin, and wrinkles easily with my clumsy application
2mil much easier to apply and feels much more robust to me. would recommend 2mil if can find.


View attachment 78362
View attachment 78363

207.2mm tall (8.1 inch tall, need 8.1 inches width total of tape)
173.93mm wide
71.65mm deep

to wrap one cell around the sides, this requires at minimum 4 faces, preferably 5 so there's no gap at the start/end.

counting distance around the cell...
left side + front + right side + back + left side
71.65mm + 173.93mm + 71.65mm + 173.93mm + 71.65mm = 388.88 mm length of tape per cell.

freedom time, 15.31 inches of tape per cell;

1 yard is 36 inches. 1 inch is 25.4mm. 1 yard is 914.4mm.

this beautiful roll of polyimide/kapton tape is 36 yards, or 1296 inches or 32918.4 mm.
View attachment 78366
https://www.amazon.com/Polyimide-Tape-Temperature-Electrical-Application/dp/B07HB9XKSD/
View attachment 78367

since that roll is 3inches wide and the cell is 207.2mm or 8.1 inches tall, we will need at least 8.1 inch / 3 inch = 2.7 and round up to 3 parallel runs of tape around the cell. so we need 3x the length of tape to cover the entire height of the cell.

recap!

15.31 inches of tape per cell
1296 inches of tape per 36yard roll.

1296 / 15.31 = 84.6 loops around the cell
84.6 loops around the cell / 3 strips wide = 28.2 cells worth of tape

28.2 cells worth of tape in the 17.95 usd roll of 1mil kapton/polyimide.

17.95 usd / 28 cells = 0.64 usd per cell for tape

64 cents per cell to wrap with polyimide/kapton seems rather affordable to me in my humble opinion.

just another option.
Guess I’m wrong. Not expensive after all.
 
Now that would be pricey.
in fairness, the 1mil thick polyimide/kapton tape will provide little physical protection, it's like paper. that stuff is like 20 usd for 100 foot/36yard roll

2mil thick kapton tape is the thinnest i can seriously recommend. it doesn't wave in the wind like 1mil tissue paper. that's more challenging for me to find..

https://www.amazon.com/dp/B07LCT7CKD

take this for example
2mil thick 3 inch wide roll - 120usd!
5mil thick 3 inch wide roll - 200usd!!

that works out to
120usd/28cells=4.28 usd per cell
200usd/28cells=7.14 usd per cell!

anyways, i have no ties to big kapton, just know that it's on space rovers and stuff and think it a neat material

tldr 2mil thick tape costs more and is the minimum thickness to get good protection imo
 
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