Precut busbar suppliers? Bus bar length?

tazzytazzy

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Nov 18, 2020
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Got my 280ah batteries from Amy. Packed very well. However, it's missing bus bars and screws, so I'm doing a bit of extra DIY. I'm new to metal working and such.

I'm looking for bus bars and it seems this website will cut to any length, is this a common thing? Copper 110 bus bars measuring 3/16 x 3/4 x 4, quantity of 7 comes to $3.82ea, plus $10 total shipping.

Some questions:
1) My eve 280ah batteries have a thickness of 71.5mm(2.81 inches). How long should the bus bars be? I am guessing around 101mm (4 inches).
2) Is this a decent price? This doesn't include drilling holes which I can do.
3) Do I have to worry about a supplier and it's quality? How would I check this? Maybe over thinking that.

Here's the website: https://www.midweststeelsupply.com/store/110copperflatbar

Anyone have a known supplier that will provide precut bars or should I just go for this one?

Thanks
 

HRTKD

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Apr 24, 2020
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I've purchased aluminum from Midwest Steel Supply. Quantity 8 of 2"x1/8"x8' aluminum flat bar. It took a little longer than I expected, but the price was better than my previous supplier. They did a better job packaging for shipment too. Midwest was upfront about extended shipping times, so it wasn't like it was a surprise.

I buy my stock in 72" lengths when it's being shipped. Your price of $3.82 each is pretty good.

When you drill your holes, they should be elongated slightly to allow for a small amount of battery expansion. This can be argued as being unnecessary if the cells are in a compression frame. I doubt that my cells are moving much, if at all, in my compression frame. If that's the case, why would I bother to elongate the hole?

I'll be making aluminum bus bars for my batteries soon. I've had the bar stock for a while, just haven't had good enough weather to get it done. My "plan" at this time is to drill holes that are slightly oversized instead of elongated.
 

tazzytazzy

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Nov 18, 2020
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Thanks for the response. Regarding the larger hole/elongated hole, are you not concerned by the less contact area of the terminal pad? I don't think the bar will 'float, around with the large hole since it will be tightened down.

How much longer should the bus bar be than the width between the terminals? 1/2 inch on each side enough?
 

HRTKD

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Thanks for the response. Regarding the larger hole/elongated hole, are you not concerned by the less contact area of the terminal pad? I don't think the bar will 'float, around with the large hole since it will be tightened down.

How much longer should the bus bar be than the width between the terminals? 1/2 inch on each side enough?

As I recall, the screw hole in my terminal is beveled. So a slightly oversized hole in the busbar isn't going to make a difference. I'm not talking about going from M6 to M12. More like M6 to M8.

The bus bar length needs to be long enough to cover both terminals. Extending the bus bar much beyond the terminal face doesn't give you any benefit.
 
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