# [EVDL] Aluminum vs copper buss bar



## EVDL List (Jul 27, 2007)

This might be a good source for copper:

http://www.stormcopper.com/

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> David D. Nelson wrote:
> > I'm adding a PakTrakr current sensor to my Gizmo and
> > need to use a buss bar. I've made one out of 1/4"
> > aluminum but I'm wondering about the issue of
> ...


----------



## EVDL List (Jul 27, 2007)

And if you are really desparate for copper bar stock, you can go down to
the local hardware store and pick up a piece of copper tubing.
Smash it flat with a hammer and fold it over as needed to achieve your
desired thickness.
Definitely dip or melt lead over it.



> > David D. Nelson wrote:
> >> I'm adding a PakTrakr current sensor to my Gizmo and
> >> need to use a buss bar. I've made one out of 1/4"
> >> aluminum but I'm wondering about the issue of
> ...


----------



## EVDL List (Jul 27, 2007)

> David D. Nelson wrote:
> > I'm adding a PakTrakr current sensor to my Gizmo and
> > need to use a buss bar. I've made one out of 1/4"
> > aluminum but I'm wondering about the issue of
> ...


----------



## EVDL List (Jul 27, 2007)

no expert but I would be surprised if alu wasn't perfectly fine for it. 
it has a bit lower conductivity but that's a matter of making it 
slightly bigger
you can do the math on how much large alu has to be to be as good as 
copper. both corrode which is why copper is coated too as I understand 
it. but I'm guessing even in the worst case scenario the most you will 
have to do is scrape the surface when you attach the wires to get good 
contact

Dan



> David D. Nelson wrote:
> 
> >I'm adding a PakTrakr current sensor to my Gizmo and
> >need to use a buss bar. I've made one out of 1/4"
> ...


----------



## EVDL List (Jul 27, 2007)

You really don't want to use Aluminium for this as Al is very noble,
so not only will you get oxidation corrosion, you'll get electrolytic
corrosion. Those together in the right conditions could corrode away a
bus bar in a few days. It is one thing to use Aluminum in a sealed
application, but in something exposed like this unless you knew how to
guard the metal against this sort of thing, you might have some
difficulty. Also, FYI, aluminum does not conduct as well as Cu, so
you'll have efficiency losses over Cu since there are so many
connections and bars.

Copper will insulate itself somewhat as it corrodes, and dipped in
lead is a much better alternative to Aluminium. Over the long haul (or
even the short one) using Cu will give you a much, much better service
life and cost you less in the way of replacements due to corrosion,
cracking, and so on.

All of that being said, there are some alloys of Aluminium
(magnesium/silicon type) that can provide excellent service life and
corrosion resistance in this sort of environment, providing better
elasticity and corrosion resistance than even pure Cu, but they would
probably end up costing as much as copper, or more, considering you
need to provide a 50% bigger cross section in order to compensate for
Al conductivity being lower than Cu.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Hi. David,

It isn't smart to use an aluminum bus bar, unless it is coated with a 
corrosion resistant metal, such as nickel.

Copper is much better, although it still should be coated (electroplated) 
with nickel. It is readily available from any electrical shop that replaces 
old loadcenters (fuse or circuit breaker boxes) with new ones. Often these 
have screw holes already drilled and tapped for small screws. Another source 
is scrappies, people who make a few bucks scrapping out metal items. New 
ones can be had from Alaska Brass and Copper, or similar outfits, but they 
will be relatively costly.

I have quite a collection of used copper buss bars myself, some about 3/16" 
thick and over a foot long - if someone needs one like that, e-mail me 
off-list at the below address.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]
----- Original Message ----- 
From: "David D. Nelson" <[email protected]>
To: <[email protected]>
Sent: Sunday, September 16, 2007 4:31 PM
Subject: [EVDL] Aluminum vs copper buss bar


> I'm adding a PakTrakr current sensor to my Gizmo and
> need to use a buss bar. I've made one out of 1/4"
> aluminum but I'm wondering about the issue of
> corrosion and resistence. The battery box on a Gizmo
> is not completely protected from moisture. Wind blows
> right over the top of the batteries and in wet weather
> it is common to have a layer of moisture on them.
> Should I go with a copper buss bar instead? If so,
> where can I get some copper bar stock since I can only
> find steel and aluminum?
>
> Thank you,
>
>
> David D. Nelson
> [email protected]
>
> http://www.austinev.org/evalbum/1328
>
>
> 
> ____________________________________________________________________________________
> Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user 
> panel and lay it on us. 
> http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

I see a lot of what I consider to be deeply irrational 'copper is much 
better than alu' posts.
the legs of power transisters are made from f'ing aluminium
alu conducts a little poorer by area than copper but make a wire 24% 
wider (or 54% greater cross section) and it will conduct just as well

by weight, aluminium is actually a much better conductor than copper

Dan



> joe wrote:
> 
> >Hi. David,
> >
> ...


----------



## EVDL List (Jul 27, 2007)

> Dan Frederiksen wrote:
> > no expert but I would be surprised if alu wasn't perfectly fine for it.
> > it has a bit lower conductivity but that's a matter of making it
> > slightly bigger
> ...


----------



## EVDL List (Jul 27, 2007)

Now that you got your copper bars, it is best to coat them. About 30 years 
ago, we could get lead sticks for vehicle body work, but these sticks are 
all lead-free solder. Not good for using on battery connectors. What I did 
was to pickup up some pure lead battery clamps and use that lead to coat 
buss bars.

You can also get pure rolls of lead from a fish and tackle store, which are 
use for making weights.

Just melting the lead and trying to coat a buss bar will not work, the lead 
will just roll off. Preheating the bar does not work good either, the lead 
looks like a cold solder joint and you can just peal it right off.

What you must do, is to clean a copper bar until it is mirror finish and 
quickly apply tinning butter which comes in 1 lb jars from www.eastwood.com. 
Use a torch to put on the tinning butter and wipe it smooth with a folded 
paper towel while it still molten. Then preheat it again and start to apply 
the lead and wipe again for a smooth surface.

It is best to use the same type of metals at the contact point. If you are 
using a zinc or cadmium plate wire lugs or battery clamps on a lead post, 
they may look bright and clean on the non-contact areas, but take one off 
after they have been on for a year, and you will see a dark tarnish area 
where the two metals made contact which increases the resistance of this 
contact.

If the buss bars are contacting other types of metals, than I silver coat 
them using a very high content of silver alloy which is use in high 
temperature welding, about 1000 F. or more. Not your basic plumbing type 
silver solder. This also takes a special tinning wetting solution. You can 
get this type of product from welding supply companies.

Roland




----- Original Message ----- 
From: "joe" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Monday, September 17, 2007 7:16 AM
Subject: Re: [EVDL] Aluminum vs copper buss bar


> Hi. David,
>
> It isn't smart to use an aluminum bus bar, unless it is coated with a
> corrosion resistant metal, such as nickel.
>
> Copper is much better, although it still should be coated (electroplated)
> with nickel. It is readily available from any electrical shop that 
> replaces
> old loadcenters (fuse or circuit breaker boxes) with new ones. Often these
> have screw holes already drilled and tapped for small screws. Another 
> source
> is scrappies, people who make a few bucks scrapping out metal items. New
> ones can be had from Alaska Brass and Copper, or similar outfits, but they
> will be relatively costly.
>
> I have quite a collection of used copper buss bars myself, some about 
> 3/16"
> thick and over a foot long - if someone needs one like that, e-mail me
> off-list at the below address.
>
> Joseph H. Strubhar
>
> Web: www.gremcoinc.com
>
> E-mail: [email protected]
> ----- Original Message ----- 
> From: "David D. Nelson" <[email protected]>
> To: <[email protected]>
> Sent: Sunday, September 16, 2007 4:31 PM
> Subject: [EVDL] Aluminum vs copper buss bar
>
>
> > I'm adding a PakTrakr current sensor to my Gizmo and
> > need to use a buss bar. I've made one out of 1/4"
> > aluminum but I'm wondering about the issue of
> > corrosion and resistence. The battery box on a Gizmo
> > is not completely protected from moisture. Wind blows
> > right over the top of the batteries and in wet weather
> > it is common to have a layer of moisture on them.
> > Should I go with a copper buss bar instead? If so,
> > where can I get some copper bar stock since I can only
> > find steel and aluminum?
> >
> > Thank you,
> >
> >
> > David D. Nelson
> > [email protected]
> >
> > http://www.austinev.org/evalbum/1328
> >
> >
> >
> > ____________________________________________________________________________________
> > Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user
> > panel and lay it on us.
> > http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Which transistors are you using? All of mine have tin plated copper leads.
--
Martin K



> Dan Frederiksen wrote:
> > I see a lot of what I consider to be deeply irrational 'copper is much
> > better than alu' posts.
> > the legs of power transisters are made from f'ing aluminium
> ...


----------



## EVDL List (Jul 27, 2007)

I think he is referring to the ones inside a CPU chip. They are silicon
with aluminum interconnects. 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Martin Klingensmith
Sent: Monday, September 17, 2007 10:59
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Aluminum vs copper buss bar

Which transistors are you using? All of mine have tin plated copper
leads.
--
Martin K



> Dan Frederiksen wrote:
> > I see a lot of what I consider to be deeply irrational 'copper is much
> 
> > better than alu' posts.
> ...


----------



## EVDL List (Jul 27, 2007)

Those aren't power transistors, and they use copper interconnects now 
anyway. Sorry not trying to be a troll.. I'll concede to irrelevance.
--
Martin K



> Dewey, Jody R ATC COMNAVAIRLANT, N422G5G wrote:
> > I think he is referring to the ones inside a CPU chip. They are silicon
> > with aluminum interconnects.
> >
> ...


----------



## EVDL List (Jul 27, 2007)

this was the spec I found online: 
http://www.statschippac.com/NR/rdonlyres/B6B4493B-58E8-4070-8CD4-EC95945AF30A/0/Power.pdf
on the specs on TO-247 on page 2 it says alu wires. maybe that's inside 
the chip?
I may have been wrong to suggest the leads are sometimes made of alu but 
it seems some part of the circuit is. either way I stand by alu as a 
good enough conductor for use as bussbar. maybe it's hard to solder on? 
maybe it's hard to nickel plate?

Dan

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

well in all fairness the one I'm considering (TO-247) doesn't say either 
way from what I can tell.
http://www.st.com/stonline/products/literature/ds/13241/stgw30nc60vd.pdf
I just once looked for what material the legs were made of in general 
(since that seems to matter heatwise) and the one I found was tin plated 
alu. obviously some could be copper.
which one is yours?

Dan



> Martin Klingensmith wrote:
> 
> >Which transistors are you using? All of mine have tin plated copper leads.
> >--
> ...


----------



## EVDL List (Jul 27, 2007)

I guess we're both wrong/right!
-
Martin



> Dan Frederiksen wrote:
> > well in all fairness the one I'm considering (TO-247) doesn't say either
> > way from what I can tell.
> > http://www.st.com/stonline/products/literature/ds/13241/stgw30nc60vd.pdf
> ...


----------



## EVDL List (Jul 27, 2007)

>maybe it's hard to solder on? 
Yes, it is

>maybe it's hard to nickel plate?
Yes again.

Bill

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

To add to Lee's post:

YES you could use Aluminium for this application. NO it will not cost
less than copper because of all of the various issues with using
Aluminium in electrical applications, and especially with Aluminium
being combustible (potentially) when in contact with iron oxide.

Essentially, all of the stuff you see using Aluminium is VERY WELL
engineered to take advantage of Aluminium's properties, and to
downplay its problems. In THIS application, to properly compensate so
that you would have aq copper equivalent, you would be spending more
money than on just buying the copper to begin with, and you still may
not have something as good as copper because you might have forgotten
something, or not taken something into account.

First, you would have to use an alloy of aluminium to do this, if you
wanted to deal with the plasticity of the metal causing contacts to
loosen.

Second, you'd have to use 50% more metal by volume.

Third you'd have to plate the aluminium in something that would
prevent the electrolytic corrosion that will happen in the acid
environment you are exposing it to. A serious zinc coating would be
good for a year or so, but thats assuming it never cracks. If it does,
you could lose a busbar in few days.

Fourth you'd have to deal with the Al2O3
(http://en.wikipedia.org/wiki/Aluminium_oxide) problem, in that it is
a decent insulator and could easily cause progressive loss, which
creates heat, which softens the metal , which causes it to shift,
which causes loosening....etc.

....and so on. It's not a simple problem to use Aluminium in
electrical work when it is exposed to weather. It works really well in
boat hulls, for example, but they have HUGE zincs under the water line
to draw away electrolytic corrosion.

This is why I am going to go through the trouble and expense of
getting nickel plated copper lugs for some BB600s I have. They are so
far superior to SS that it isn't worth the hassle (for me) or the
losses. I know I know.. there are peopole using SS lugs with BB600s..
I just dont want to take that risk. 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Metalization on the IC itself is often aluminium, or an alloy of it. Bonding
wires are most commonly aluminium or gold. Gold has historically been used.
Neither metalization nor bonding wires need to be soldered - they are welded
instead. Different alloys need to be layered to make flip-chips (which can
be soldered) - each metal layer offers a specific function as the basic IC
metalization is not suited to soldering. Cr, Cr-Cu, Cu, and Au layers are a
common layer stackup. Al, Ni, Cu is another stackup.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> Dewey, Jody R ATC COMNAVAIRLANT, N422G5G wrote:
> > I think he is referring to the ones inside a CPU chip. They are silicon
> > with aluminum interconnects.
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Dan Frederiksen wrote:
> > well in all fairness the one I'm considering (TO-247) doesn't say either
> > way from what I can tell.
> > http://www.st.com/stonline/products/literature/ds/13241/stgw30nc60vd.pdf
> ...


----------



## EVDL List (Jul 27, 2007)

says who? have you tried?



> [email protected] wrote:
> 
> >>maybe it's hard to solder on?
> >>
> ...


----------



## EVDL List (Jul 27, 2007)

you sound like you know what you are talking about. do you know if there 
are any particular problems with nickel plating alu?
more so than copper



> Dale Ulan wrote:
> 
> >Metalization on the IC itself is often aluminium, or an alloy of it. Bonding
> >wires are most commonly aluminium or gold. Gold has historically been used.
> ...


----------



## EVDL List (Jul 27, 2007)

Yes, you can solder aluminum, but it takes a special solder, call aluminum 
solder that you can get from a some welding supply companies. You must also 
use a wetting tinning solution. You must use a gas/oxygen torch set at a 
small pencil flame to use this solder.

Radiator shops use this type of solder for aluminum radiators.

This is not heliarc welding. A good technician can solder a large thick 
block of aluminum to a paper thin piece of aluminum that looks very smooth 
and looks like it was stamp out of one piece.

Roland


----- Original Message ----- 
From: "Dan Frederiksen" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Monday, September 17, 2007 12:20 PM
Subject: Re: [EVDL] Aluminum vs copper buss bar


> says who? have you tried?
>


> > [email protected] wrote:
> >
> > >>maybe it's hard to solder on?
> > >>
> ...


----------



## EVDL List (Jul 27, 2007)

[No message]


----------



## EVDL List (Jul 27, 2007)

years, of all kinds of brands, many of which not designed to be repaired. I 
have no recollection of seeing a semiconductor device that used aluminium 
for its' electrical connections.


Not to the outside world, but the bonding wires between the legs of the
transistor or IC and the die itself are (reasonably) often aluminium.
But you never see that, unless you take something like a power IGBT
module or automotive ignition module apart. Those wires are welded to
the IC die and the leadframe, before the part is encapsulated.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

In a message dated 9/17/2007 11:27:27 AM Central Daylight Time, 
[email protected] writes:

well in all fairness the one I'm considering (TO-247) doesn't say either 
way from what I can tell.
http://www.st.com/stonline/products/literature/ds/13241/stgw30nc60vd.pdf
I just once looked for what material the legs were made of in general 
(since that seems to matter heatwise) and the one I found was tin plated 
alu. obviously some could be copper.
which one is yours?

Dan


Well, I certainly haven't seen everything, but, so far, I have never seen any 
semiconductor with an aluminum leadframe.

The ST semiconductor packaging material data sheet can be found at: 
_http://www.st.com/stonline/company/environm/report03/envi03.pdf_ 
(http://www.st.com/stonline/company/environm/report03/envi03.pdf) 
Page 7 describes the leadframe materials of all their semiconductors and page 
57-58 provides leadframe materials used in all medium/high power packages.

Ken




************************************** See what's new at http://www.aol.com

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Found another potentially really good local source for brass bus bars:
http://www.metalsupermarkets.com/

They cut to length and can even punch holes in it.

They very likely have a store in your state(or country):

http://www.metalsupermarkets.com/MSC-storefinder.aspx

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------

