Shorter (7cm) busbars: what are they for?

[trougnouf]

Hello all,

I just received my 304Ah EVE battery cells ordered on Alibaba and I am very confused about the busbars I got:

A box contains two 9 cm long busbars which allow connecting two cells sandwiched together (since I calculated the cell terminals center would be about 7.35 cm apart including minimal padding),

and 3 *shorter* 7 cm busbars, which don't seem useful in any way. The side to side terminal distance should be approximately 8.5 cm (including minimal padding) so the side-to-side busbars should actually be longer.

Am I misunderstanding something?

I was initially confused about this and assumed the seller (Amy) made a mistake when she told me that the "longer" busbars were actually "shorter", I had to order more busbars anyway because I wasn't getting enough for 25.6v / 2*12 cells battery so asked her about this at the same time, but haven't received a response so I think I'm on my own as far as creating more busbars anyway.

(the 7cm busbar is the one I just drew in the middle in this picture. the longer 10 cm ones shown there are what I assumed I would be receiving based on what made sense in my plan but I don't have those)

 

[HRTKD]

Maybe you got bus bars for a different size cell?

 

[trougnouf]

I guess so, that's all I can make sense of. Amy ended up getting back to me after I told her I received the batteries so I will ask her about it after I double check the size of the cells I got.

 

[trougnouf]

Got home and measured them, I think it's the eve datasheet / product specs that are wrong. I measured approximately 2.5 cm between the terminal and the smaller edge of the cell, which seems to match with the smaller busbars I received.

The datasheet shows 9 cm between terminals which would mean approximately 4 cm from terminal to small edge.

The width and length of the cells seem to match (though I didn't measure anything precisely).

 

[kid744]

Can you tell us which vendor? There are multiple Amy's.
Thanks,
Kid

 

[trougnouf]

Can you tell us which vendor? There are multiple Amy's.
Thanks,
Kid

Yes, I got them from Shenzhen Luyuan Technology Co., Ltd.

Besides forgetting to respond to my messages when I initially asked about more busbars they've been lovely and very helpful.

It will still be a little while before I have everything setup and tested; FreeCAD plans are slowly being finalized, currently 5 of the 6 shipping boxes are still unopened and the houseboat they will go in isn't ready to welcome them. (I will have to assemble them in place because the final battery will be too heavy to ever move.)

 

[kid744]

Thanks! I am going to be ordering batteries in the next couple of months and am collecting info on vendors to help decide who to go with.

Kid