Bog's Modular PW

bogptrsn

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Joined
Oct 27, 2017
Messages
34
Getting closer. Been working on this since 2017. Many different designs but feel confident in this design.


image_eqjfqz.jpg



image_xcdpxf.jpg



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Bog
 

Oz18650

Active member
Joined
Oct 2, 2017
Messages
200
Welcome!
What are the details of the design you will be using?
If I am following correctly, it looks like you are using 14S28P on the board?
I hope everything goes well for you.
 

Eratigena

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Feb 2, 2018
Messages
3
I like your simplistic design! Do you plan to make several vertikal slide-outs? In germany we call that "apothekerschrank" for the kitchen. Slim and high vertikal drawers. Or how do you plan to install and increase the wall as whole concept?
 

bogptrsn

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Joined
Oct 27, 2017
Messages
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Oz18650 said:
Welcome!
What are the details of the design you will be using?
If I am following correctly, it looks like you are using 14S28P on the board?
I hope everything goes well for you.

I am using 6p modular packs so it will have the potential to be 14s168p.


Eratigena said:
I like your simplistic design! Do you plan to make several vertikal slide-outs? In germany we call that "apothekerschrank" for the kitchen. Slim and high vertikal drawers. Or how do you plan to install and increase the wall as whole concept?

The max will be 14s168p. Currently I have enough processed cells for 14s132p.


Do BMS leads need to be the same length? With my design I plan on having the BMS off to the left side and did know if it matters if the BMS leads are different length when talking about 6'. Here is a picture of my fusing.

image_lpcvzk.jpg
 

bogptrsn

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Joined
Oct 27, 2017
Messages
34
Sorry my question got buried in my previous reply. Do you recommend balance leads being the same length? Right now if I did not make them the same length they would vary from 18"-72". Should I make them all 72"? It will look worse but may balance better. Thoughts?


image_ouoqbn.jpg


Close up of fusing.
 

Korishan

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Jan 7, 2017
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6,445
I did quick calculation (Voltage Calculator) and here's the results:

Wire Size: 28 AWG
Wire Length: 1Ft
Line Voltage: 5V
Line Amps: 0.5A
Voltage drop: 0.065
Voltage drop percentage: 1.30%
Voltage at the end: 4.935

Inputting your wire size, balance current, and wire lengths will make the above calculations more accurate.
 

bogptrsn

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Joined
Oct 27, 2017
Messages
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Korishan said:
I did quick calculation (Voltage Calculator) and here's the results:
...

Inputting your wire size, balance current, and wire lengths will make the above calculations more accurate.

Very helpful. Thank you. Didn't realize such low voltage and short distances had that much loss.
 

Korishan

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Remember depending on the amp draw, it'll effect the voltage drop. Same goes with wire size. So maybe you want the wires to be 26 AWG instead of 30 AWG for instance. I used 5V as it made things easier to test, but you need to check the calcs based on what "your" high voltage will be. Some do 4.2V, others 3.8V. Just depends on what you are going to limit your voltages to.
 

RikH

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Joined
Nov 22, 2018
Messages
85
bogptrsn said:
It will look worse but may balance better. Thoughts?


image_ouoqbn.jpg


Close up of fusing.

I understand what you mean. You make it visual attractive as possible as far as I can see. Can't you put the balance leads in a tube or something? Make a hole where it should come out. Inside you can make them all the same length. Nice setup by the way!
 

Korishan

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If you "really" want to make the balance leads the same length and make them visually appealing, you could just make them a little longer, and the furthest one have 1 loop, then would get an extra loop with each one closer to the unit.
Another option would be to put the bms in the middle and run the wires out from it like a spider web kind of thing, but you'd still need some kind of loops.

Oooorrrr, you could have each strand go out to it's respective section, then dip down behind the board and then show back up right next to the spot where it dipped. The only difference between each run would be how much wire is "behind" the board that isn't visible. But from the front, you wouldn't be able to see how long the wires were.

Another idea would be to run the wires through a grove made in the board. Then as each wire passes another section, another wire is added and the grove gets a little bit wider and all the wires are ran ribbon style up to the bms.
 

XtronX

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Joined
Nov 27, 2019
Messages
3
How's your project? I think it's a really cool build.
 

bogptrsn

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Oct 27, 2017
Messages
34
XtronX said:
How's your project? I think it's a really cool build.
Been busy so I haven't moved very far from my last post. Should have more time soon so plan on getting at it again.
 
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