90 degree lug positions

[JJJJ]

Frustration.... Am trying to attach two lugs at 90 degrees from each other. This is for a battery to a terminal connection. It is a very short section of wire so the lugs nearly touch each other.

Each time I do this, one of the lugs shifts just a little taking it out of position. This keeps the lug from having a solid position on the terminal.

If only there was a swivel connection for something like this...

 

[timselectric]

Use a bus bar.

 

[JJJJ]

OK. I took another look at this. Channel locks and lineman pliers are very handy tools. I made sure the crimp connections were solid. Then with careful gentle movement was able to adjust the lug ends just enough to ensure a solid connection.

 

[timselectric]

I hate to say this but the lug hole is too big for the battery terminal to make a good connection.
Also make sure that the balance wire is on top.

 

[Steve_S]

This is NOT good !

That hole should be 1/4" or at worst 5/16"
You need as much surface contact between the lug/busbar & the terminal interface, do not consider the thread for carrying power.

Always place the BMS Leads ON TOP of busbar/lug

 

[JJJJ]

OK. Duly noted. Thank you for the feedback.

 

[OzSolar]

Building on Tim's suggestion

What about putting one end of bus bar in a vice and twisting the 90 into it with a pair of vice grips? That seems feasible. Might take a few tries to get it right.

 

[chrisski]

OK. I took another look at this. Channel locks and lineman pliers are very handy tools. I made sure the crimp connections were solid. Then with careful gentle movement was able to adjust the lug ends just enough to ensure a solid connection.
View attachment 130755

IME, 1/4” busbars are good for flat connections, but are extremely unforgiving. With zero flexibility, If both connections are not perfectly level to a degree less than my ruler can measure, perhaps 1/100th of an inch, the bar may not sit level on the stud and have a bad connection and cause heating.

A busbar could probably be fabricated for what you want and would be the best solution, unfortunately for me, that is beyond my fabrication skills. Especially with such a small area to work with, the small contact size, and busbar costing about $2 per inch.

Wire is the best way, but finding 1/4” lugs for thick wires is challenging.

 

[timselectric]

A company that I used to work for would buy lugs without holes. And we field drilled them for the application. I don't remember where they got them. And haven't seen them since. But, a bus bar is always a better option. If you can make it work.

 

[Steve_S]

Wire is the best way, but finding 1/4” lugs for thick wires is challenging.

Selterm carries them, that is where I get most of my lugs and now they are expanding their product lines to include proper Butt Connectors and more. https://selterm.com/

4mm Thick X 20mm Wide busbar would do the job quite nicely and can easily be shaped by using a Bench Vice and a good vice grip going slowly. Then once shaped to fit properly put the busbar into a High Quality heat-shrink tube to cover the exposed metal.

 

[JJJJ]

Already ordered some from Selterm. Was impressed with their quality. Never hurts to have proper parts in stock.

Like the bus bar suggestion. Next thing on the purchase list.

 

[chrisski]

Selterm carries them, that is where I get most of my lugs and now they are expanding their product lines to include proper Butt Connectors and more. https://selterm.com/

Thanks.
I do like @timselectric suggestion of lug blanks. As best as I can tell, lugs are made by taking a tube and crimping one end flat. It would be nice as he suggested if these lug blanks were available for as to drill holes.
https://selterm.com/

4mm Thick X 20mm Wide busbar would do the job quite nicely and can easily be shaped by using a Bench Vice and a good vice grip going slowly. Then once shaped to fit properly put the busbar into a High Quality heat-shrink tube to cover the exposed metal.

My fabrication skills are less than stellar, so what do you do to prevent the vice grips from scarring the copper? My idea would be to make it an inch or two longer and cut the scarring out.

Also, do you do anything at the bending point like take a torch to the copper to get it nice and hot?

The copper bars I have worked with are rated to about 300 amps and are 1/4” by 3/4”, about 6 mm X 19 mm.

Drilling busbars cost me $2 per inch to learn, so if I did bend mine, I’d want to be sure. Some of the Youtube videos I watch on this topic is something I’m not sure I’d want To do.

 

[Steve_S]

Well, I am a recovered Hot Rodder / Auto-Restorer (also have bodyman licence) so bending & forming metal to me is like blowing my nose, I just do it without thought anymore. Plus I have the tools which I use but 99.5% of folks won't have the kit.

I mentioned Vice Grips because most folks do have those at hand and if not, they are everywhere so easy & cheap to get. If one needs to be purchased, be sure to get a long wide nose. You can put tin or steel between the vice-grip jaws and the work piece to prevent scarring. Tape & other "softs" will work but you need a lot of it and it adds "slack" because tape "gives" when applying pressure - it can be done but slow & easy get's you there.

There should be no need to heat the copper to bend it, it's a soft metal and will not crack BUT you need to be able to apply pressure/force and of course the thicker it is the more force you need to apply. a Simple solution is to use a Long Steel Tube than you can slip the Vicegrip handle into and use the leverage it affords you to bend the thicker metal. 4mm to 8mm copper does not need that much force, really, it doesn't. (I suppose that depends if you're a 90Lb dude or a 200lb football player)

hope it helps.

 

[JJJJ]

I would imagine it might be good to cut the bar just a little longer before twisting it? It has been many years since I have worked with sheet metal and never with copper bar before.

I love the opportunity to get another tool. One of my favorite sayings is “new project, new tool”

 

[timselectric]

Yes
You can always cut it shorter. But it's hard to stretch.

 

[OzSolar]

I would imagine it might be good to cut the bar just a little longer before twisting it? It has been many years since I have worked with sheet metal and never with copper bar before.

I love the opportunity to get another tool. One of my favorite sayings is “new project, new tool”

If possible I wouldn't cut it until I had twisted it.

 

[JJJJ]

Excellent advice. My mechanic friend made the same suggestion as well.

Thank you

 

[JJJJ]

Really appreciate all of the suggestions.

The talent on this site never ceases to amaze me.

An order was placed today for copper bus bar material. Will definitely be looking at the use of protected vice grips, a bench vice and rotating prior to cutting.

Fortunately the lug assembly already built will provide a template during the build process.

Thank you again everyone!

 

[Bud Martin]

BTW, the ring lug should make direct surface contact with feed through terminal base, it looks like you have washers underneath the ring lug.

 

[JJJJ]

This conversation prompted me to check the other potential lug connections in the system. Turns out as is, connections on the inverter and distributor would have had the same problem, the lugs were too big.

I will be updating the inventory to get lugs better suited to these sizes. Thank you again for helping me think in this direction.

 

[HRTKD]

My thoughts on this, in no particular order:
1. Don't position the terminal (on the battery box) so close to the battery terminal.
2. Position the terminal (on the battery box) closer, like right in line with the battery terminal so all you need is a single 90°F bus bar.
3. Make the cable longer. Yes, longer sucks, but it gives you more options and doesn't require a perfect crimp.
4. Making a 100% bus bar connection would be difficult. There's too many angles involved. To do it all with bus bars, I think you would need two pieces. One with a 90° bend, the other without. Connect the two with an overlapping joint.

 

[timselectric]

A 45° fold makes a 90° bend.
I would slip the heat shrink over it before completing the fold. You'll thank me for that tip. lol

 

[HRTKD]

A 45° fold makes a 90° bend.

That's a good point. I tried making a 90° bend with some aluminum flat bar and it was good up to about 70°, then the corner started to deteriorate.

 

[JJJJ]

45° fold makes a 90° bend.

That is an interesting idea. Two 45s to get a 90. I also like the suggestion of putting the attachment terminal closer to the positive on the battery. It would allow for a straight run and could simply things considerably

 

[timselectric]

That is an interesting idea. Two 45s to get a 90. I also like the suggestion of putting the attachment terminal closer to the positive on the battery. It would allow for a straight run and could simply things considerably

Not two 45's
one 45° fold.