13s4p 48v battery cell layout help
- Thread starter nocarrier
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eMark
100 kW
13s4p = 52 18650 30Q 3000mAh 15A cells - 12Ah capacity ... $274 ... Samsung 30Q 18650 3000mAh 15A Battery
13s3p = 39 21700 BAK 5000mAh 15A cells - 15Ah capacity .. $225 ... BAK 21700 5000mAh 15A Battery (N21700CG)
Shouldn't be a problem arranging only 39 (3p) cells compared to 52 (4p) cells. Then won't be necessary to offset cells for hot gluing together for twelve or eleven 2s3p and one or two 1s3p to fit available space.
Isolation between cells needed? ...
endless-sphere.com
[IMG alt="spinningmagnets"]https://endless-sphere.com/sphere/data/avatars/m/5/5883.jpg?1676495170[/IMG] spinningmagnets - Apr 9, 2021
"The cells in the center of the pack will run hotter than the cells at the edge, which can passively shed "some" heat. This means the cells that are not on the edge will degrade sooner, and the pack will have reduced capacity when those cell degrade.
As a general rule, I am not a fan of hot-gluing.
I understand the desire to pack as many cells as possible into the limited space of the frame. If the cells can put out much more current than the controller/motor/throttle demand from them, then...the cells will not get "hot", but perhaps just warm."
13s3p = 39 21700 BAK 5000mAh 15A cells - 15Ah capacity .. $225 ... BAK 21700 5000mAh 15A Battery (N21700CG)
Shouldn't be a problem arranging only 39 (3p) cells compared to 52 (4p) cells. Then won't be necessary to offset cells for hot gluing together for twelve or eleven 2s3p and one or two 1s3p to fit available space.
Isolation between cells needed? ...
Isolation between cells needed?
I just built my first pack, 16Ah, 72V nominal. I glued the cells together with hot glue before welding and incased with heat shrink. After the build I saw some videos saying that it is important to add isolation between the cell groups. Is this an important safety issue? Should I be warried...
endless-sphere.com
"The cells in the center of the pack will run hotter than the cells at the edge, which can passively shed "some" heat. This means the cells that are not on the edge will degrade sooner, and the pack will have reduced capacity when those cell degrade.
As a general rule, I am not a fan of hot-gluing.
I understand the desire to pack as many cells as possible into the limited space of the frame. If the cells can put out much more current than the controller/motor/throttle demand from them, then...the cells will not get "hot", but perhaps just warm."
Last edited:
From-A-To-B
100 W
Your battery layout mostly looks good, but you've got at least two bottlenecks, especially if this will be connected with .15mm nickel. The blue lines are examples where you can fit 4 series connections and neatly chare current amongst the cells. The orange lines represent the bottleneck areas, at least in how I imagined you'd lay the nickel. There, you'll need to lay multiple layers of nickel or potentially start working with copper, depending on how much current this battery is going to deliver.
.15mmx10mm nickel strip is good for 5-7amps tops. So you've got potential problems, especially in that middle "T" series connection.
It's hard for me to recommend what you should do because I don't know the space you are working with or what the battery needs to do. More information would be helpful.
IMO - never skip cell holders, and hot glue is a poor excuse of a cell-holding material. Others have different opinions on this, and even I have used hot glue in the past... but there are better ways to hold cells and isolate cell groups.
.15mmx10mm nickel strip is good for 5-7amps tops. So you've got potential problems, especially in that middle "T" series connection.
It's hard for me to recommend what you should do because I don't know the space you are working with or what the battery needs to do. More information would be helpful.
IMO - never skip cell holders, and hot glue is a poor excuse of a cell-holding material. Others have different opinions on this, and even I have used hot glue in the past... but there are better ways to hold cells and isolate cell groups.
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