# Headway 3 cell holder



## Yabert (Feb 7, 2010)

Hi

Someone have experience assembly with 3 cell holder for the 38120S headway cells?

That work fine?
How the fixation from two and more holder worked?
Do you have picture of some assembly exept those ones below?

I thinking about fixing 384 headway 38120S cells with those holder. Good idea or no?

Thanks


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## DavidDymaxion (Dec 1, 2008)

I found the little bus bars would not fit with this style of holder. You'll need to do custom bus bars (probably a better idea anyway for a large number of cells). I didn't try it, but it looks like the little bus bars would work fine with the 4 cell holders that arrange the cells as a grid rather than a honeycomb.


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## Yabert (Feb 7, 2010)

Yeah! It's why I think used costom bus bar like those ones below.

So, in fact, this kind of assembly with cells holder seem nice...., but someone know if the hundred of plastic connexion will work fine?
Or it's more like crappy plastic holder with inacurate dimensions?

Well, someone have experiment those 3 cells holder to do an assembly?

Thanks!


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## steven4601 (Nov 11, 2010)

Hi,

Nice pack, Id like to do something very similar. The fact that the headway cells need some sort of support to prevent mechanical stress at their electrical connections made me worried about that layout.

How are you going to prevent the cells from flexing their electrical connections? 

Connecting the cells like this is quite practical space wise, but require intensive care for mechanical rigidity of the battery box to prevent flexing. 

Also on a side note, have you considered variation in cell series-impedance causing unequal cell load & temperature aggravating the effect when using low-impedance bus-bars between every series-stage of your pack? 


Steven


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## DavidDymaxion (Dec 1, 2008)

I only hooked up 2 of them, but was impressed with the strength and how accurate the fit was.

It looks like I would have the same issue as in the pic, an extra ring that I would need to cut off.

To get the number of cells I want to fit, the honeycomb style packs in slightly more cells than the square grid style.


Yabert said:


> ... So, in fact, this kind of assembly with cells holder seem nice...., but someone know if the hundred of plastic connexion will work fine?
> Or it's more like crappy plastic holder with inacurate dimensions?
> 
> Well, someone have experiment those 3 cells holder to do an assembly?
> ...


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## Yabert (Feb 7, 2010)

DavidDymaxion said:


> I only hooked up 2 of them, but was impressed with the strength and how accurate the fit was.


Thanks! It's exactly what I need to know.
Others experiment?




> an extra ring that I would need to cut off


Yeah! 9P (90Ah) would be just perfect, but I don't have the extra space needs for 48 more cells. I will just cut it.


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## Yabert (Feb 7, 2010)

Any other recommendation? 

Manzanitamicro guys!
Currentevtech guys!

Comments please!

Thanks


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## frodus (Apr 12, 2008)

I've had several customers use those holders without any issues. They're pretty nice little holders. I think the older style of red ones weren't as strong.

They're cheap and easy. the only reason I chose to make my own holders is because of the weird shape of my pack. I'd say they're a good fit for a project that needs staggered cells.


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## DavidDymaxion (Dec 1, 2008)

I bought a small number of cells from Manzanita Micxro, I was happy with their service.


Yabert said:


> Any other recommendation?
> 
> Manzanitamicro guys!
> Currentevtech guys!
> ...


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## Yabert (Feb 7, 2010)

Thanks!
I will continue my design with these cells holder.


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## steven4601 (Nov 11, 2010)

how are you going to overcome stressing the electrical cell connections when connecting them end-to-end ?


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## Yabert (Feb 7, 2010)

I won't do!

After two years to play with Headway cells, it seem than the negative end is the weakest link on cells...
The positive end seem strongly fixed to the cells.

So in fact, I will only support the negative end with the holder. The bus bar will connect the 8 cells end to each other to add strenght to the assembly.
I think the friction generated by the set screw between each cells ends and the bus bar will isolate the cells end from each other.
The cells holder will be here to support each negative ends and connect each three cells to each other to do a complete bloc of 384 cells.

Wish me good luck...


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## steven4601 (Nov 11, 2010)

Well no structure is perfectly rigid so expect flexing the battery pack .


What I was trying to explain the negative end will be experiencing torsion from the flexing. 

It does not matter where you place the cell blocks. What matters is how you prevent the pack from bending/flexing.


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