# aluminum wire last chance-tesseract



## lou-ace (Jul 21, 2009)

hey guys I have this marvelous aluminum 4-0 guage house supply line ( left over from a housing rebuild) that I am dying to use for my small truck ( 9" AMD motor 120v, curtis 1331c 500 amp, #20 trojan t145's 28.8 kw I think!!). this stuff is the size of my thumb , new, and not that rigid...... with my house current being 120v x 200 amp service wouldn't that mean that this wire is rated at 24 kw? is that close enough? I guess I could wire it up and see if I have any heat or voltage issues?,,,,,,,,,,,,,,,,, and if not what guage would you use of the fine stranded vs. coarse copper stuff? waddya think


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## major (Apr 4, 2008)

lou-ace said:


> hey guys I have this marvelous aluminum 4-0 guage house supply line ( left over from a housing rebuild) that I am dying to use for my small truck ( 9" AMD motor 120v, curtis 1331c 500 amp, #20 trojan t145's 28.8 kw I think!!). this stuff is the size of my thumb , new, and not that rigid...... with my house current being 120v x 200 amp service wouldn't that mean that this wire is rated at 24 kw? is that close enough? I guess I could wire it up and see if I have any heat or voltage issues?,,,,,,,,,,,,,,,,, and if not what guage would you use of the fine stranded vs. coarse copper stuff? waddya think


Hey ace,

I think you'll have trouble with aluminum wire. The problems reside in the terminations or connections. They do make aluminum lugs, but they are large and expensive. And then you still have the problem of the aluminum lug surface to the component surface which is unlikely aluminum.

I have experimented with aluminum 2/0 cable and have had a test piece on my battery test stand for years with no problem. I used standard copper lugs with a copalum insert. The inserts are only sold in specialized connectors and splices. And, IIRC, cost $5-10 apiece. And then my battery test stand is not subject to vibration and weather as you will find on an EV.

And another thing, the kW rating doesn't apply to wire. The conductor material and cross section determine the ampacity, or current carrying capacity. The insulation determines the voltage rating, and also the temperature rating, which in turn relates back to the ampacity. Power (kW) really does not enter into the cable specification directly.

The only way I have seen aluminum conductor work well in EV related equipment is in the form of busbars and busplates which have been nickel plated.

You can consider making all connections to the aluminum cable with set-screw compression devices. Even then, you'll have trouble with dissimilar metals and electric current. They make antioxidant grease for this. But overall, what you gain in a few pounds you will lose in reliability eventually.

My take on it.

major


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## rwaudio (May 22, 2008)

major said:


> Hey ace,
> 
> I think you'll have trouble with aluminum wire. The problems reside in the terminations or connections. They do make aluminum lugs, but they are large and expensive. And then you still have the problem of the aluminum lug surface to the component surface which is unlikely aluminum.
> 
> ...


Aluminum wire has about 2/3 to 3/4 of the current capacity of OFC copper wire but weights 1/3 as much as copper. For the same current capacity aluminum is half the weight of copper, this is a big deal. Most connectors/terminals etc aren't copper or aluminum, they are going to either be brass or plated with nickel/tin etc. It has been mentioned that TS LiFePO4 cells have aluminum terminals (I can't confirm this personally). I've used CCA (copper clad aluminum) wire extensively in car stereo installs because it is lighter even when you factor in the larger size required for the lower conductivity. I would say this may be an important factor for those that are trying to keep the weight down on their EV. I personally am less concerned about weight in the EV, however I will still likely use CCA wire (I'm not sure if it's rated for the voltage, I will have to check before using it and you should do the same) I will probably ADD sound deadening material to the car, this makes the perfect car stereo platform. VERY Quiet!


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## major (Apr 4, 2008)

rwaudio said:


> Aluminum wire has about 2/3 to 3/4 of the current capacity of OFC copper wire but weights 1/3 as much as copper. For the same current capacity aluminum is half the weight of copper, this is a big deal.


Hi rw,

Ever wonder why production EVs and HEVs have never used aluminum wire? Or even any of the standard ICE automobiles made by the millions? The OEMs spend millions on weight reduction efforts. And have never put aluminum wire into a car, to my knowledge. Wonder why?



> Most connectors/terminals etc aren't copper or aluminum, they are going to either be brass or plated with nickel/tin etc.


I use copper connector lugs all the time.

Regards,

major


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## DavidDymaxion (Dec 1, 2008)

Aluminum expands and contracts, leading to connection problems.

Many building codes now prohibit Aluminum wiring.


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## racunniff (Jan 14, 2009)

DavidDymaxion said:


> Aluminum expands and contracts, leading to connection problems.
> 
> Many building codes now prohibit Aluminum wiring.


Well, not necessarily prohibit - they just require the proper terminations to resist the expansion / contraction.

One additional issue - aluminum is more vulnerable to work hardening and subsequent stress fractures than most metals. In the environment of a car, I would expect that cracks and failures would develop in a thick aluminum wire long before it would in finely stranded copper.


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## rwaudio (May 22, 2008)

The reason is until recently the cost of copper was quite resonable, however with the increasing cost of copper there are now some high quality aluminum or copper clad aluminum wire alternatives.

Copper lugs are available, and I use them as well with the copper clad aluminum wire, I've also used aluminum distribution blocks with both types of wire with no ill effects, I do use "de-oxit" in any connections that can't be soldered.

There is no difference in using an aluminum buss bar and using an aluminum wire (providing it has the flexibility/insulation to work in the automotive enviroment)

Your comment about OEMs not using aluminum wire is similar to them not using electric motors. (some have probably played with it, but perhaps it never made it to a final product because it wasn't worth doing at the time, but times are changing) I think we are all here to do something different, aluminum wire is a safe alternative as long as a suitable type of wire is used and it is used within it's working parameters just like copper wire.


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## rwaudio (May 22, 2008)

racunniff said:


> Well, not necessarily prohibit - they just require the proper terminations to resist the expansion / contraction.
> 
> One additional issue - aluminum is more vulnerable to work hardening and subsequent stress fractures than most metals. In the environment of a car, I would expect that cracks and failures would develop in a thick aluminum wire long before it would in finely stranded copper.


I'm not an aluminum expert, I'm just stating good experience with copper clad aluminum wire. However a quick google search brings up quite a bit of info about reserach into automotive use. One example:
http://www.springerlink.com/content/m247r46304531239/
So aluminum wire might not be far off mainstream use by OEM's especially if the price of copper keeps going up it will kickstart the research required in making a suitable aluminum alloy.

I think the problem with aluminum wire is it being used as a direct 1:1 replacement for copper wire, which will cause problems regardless of where and how it is used.


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## EVfun (Mar 14, 2010)

rwaudio said:


> It has been mentioned that TS LiFePO4 cells have aluminum terminals (I can't confirm this personally). I've used CCA (copper clad aluminum) wire extensively in car stereo installs because it is lighter even when you factor in the larger size required for the lower conductivity.


The terminals on TS LiFeYPO4 cells (the newer ones) are aluminum on the positive side and copper on the negative side. I "wet sanded" my aluminum terminal using noalox then wiped that off and put a thin coat of fresh noalox on the terminals before installing the bus bars. The copper terminal where just dry sanded lightly to brighten then wiped off and given a thin film of noalox.

CCA is an interesting idea. The biggest problem with aluminum connections seems to be the oxide film that develops on it.


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## Tesseract (Sep 27, 2008)

Three other people here have already covered the main problems with using aluminum wiring in an EV:



major said:


> You can consider making all connections to the aluminum cable with set-screw compression devices. Even then, you'll have trouble with dissimilar metals and electric current.





DavidDymaxion said:


> Aluminum expands and contracts, leading to connection problems.





racunniff said:


> ...One additional issue - aluminum is more vulnerable to work hardening and subsequent stress fractures than most metals. In the environment of a car, I would expect that cracks and failures would develop in a thick aluminum wire long before it would in finely stranded copper.


See, you didn't need me for this at all. And speaking of... seeing "tesseract" in the title line was kind of creepy.


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## peggus (Feb 18, 2008)

Well, let me add one more reason not to use it. Aluminum corrodes very easily, not a good property when you have lead acid batteries, especially flooded ones.


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