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Battery Cable Upgrade Kit

The wheel is handy but when you throw power into it you need to watch carefully. The rest of your post was right on but the old teacher in me couldn't let the little error go.:thumb
 
Aluminum is a notoriously poor conductor.

Actually Aluminum is a pretty good conductor (fourth best metal after silver, copper and gold) but corrodes very easily which drastically affects the conductivity of any mechanical joint in the circuit. If the connection points are kept clean and protected from contact with the air (in power wiring they use a substance called Penetrox) it will function almost as well as copper. Cleaning and protecting all grounding points on any vehicle that uses the chassis as the common for it's electrical circuits would be part of good maintenance practice especially if you live in a warm, humid environment (particularly near the ocean).
 
I'm hoping that someone will chime in with a source for quality battery wire so us hands-on guys (cheap) can make our own. I can find wire locally, but it's not the high strand count like the original.

Ed
 
It seems that an improvement in current carrying capacity by using a larger conductor as in this case would be based on the original cable having insufficient capacity to do the job while the replacement does.

Did the BMW engineers specify a cable that due to size & length was ill suited to the job?

Short of working on the starter or replacing the charging system who ever goes into the engine to test & clean the positive cable at the starter? Supposedly in the past, curmudgeonly airhead owners claimed to disconnect, clean & grease every connection on their bikes yearly or so. Seems a bit unlikely to me.

I am more surprised at the small size of the cable that connects the rest of the bike's electrical system at the same starter post.
 
Wire source?

I used to be a buyer at a large corporation and have purchased thousands of feet of wire. I would guess, though I am not sure, that any of the large electrical supply houses (I worked mostly with Rexel and Graybar) would have just about any wire you could want. The problem may be, though, that they will want you to by a minimum amount which may be a roll of a hundred feet. I know that our local Rexel outlet, will sell at the will-call counter and maybe you could get smaller lengths - and probably the connectors too.

They are located all over the US, so give a local one a call and find out.
 
Welding wire cable is sometimes used, as it is a high strand-count (for flexibility) with good current carrying capacity (amps!).... check welding supply stores. Stick with larger (4ga) and you should be just fine....:drink

;)
 
+1 on the welding cable. Your local NAPA guy can generally crimp cables which you can then solder over.

But why be so cheap? Any perfectionist knowns you could can get a tiny bit more conductivity from silver wire- its available if you want to spend the $... smaller gauges actually used as speaker wire in some AV aps but hideously expensive.
 
Do you buy in to this logic?

I can't tell you because I didn't bother reading all of that. And I certainly would not spend $50 for cable I can make better for a fraction of that.

You want zero voltage drop across any cable. That means zero resistance, which isn't realistic.

So you take an acceptable voltage drop of 0.1V and divide it by 100A for a resistance of 1 milliohm for the length you need.

You can look up wire specs on any manufacturers site. Resistance is usually given for 1000 feet, so do some simple math to get it for 1 foot and go from there.

I made a ground cable for a local. Crimped the terminals and then flash soldered the ends where the cable stuck out. Resistance for a 13" cable was 0.000714 ohms (measured with an Agilent 33420A 4-wire meter).

Specs of the wire used:

Number: M22759/16-8
Gauge: 8 AWG
Stranding: 133/29
Diameter: 0.199 inch
Resistance @ 20??C per 1000 feet: 0.701 Ohms. (looks like that confirms my measurement at 1 foot = 0.0007 Ohms

Standard wall ethylene-tetrafluoroehtylene (ETFE) insulation ( also known as Tefzel ) designed for aerospace applications where weight, dimensional tolerance, and mechanical durability are required. This wire exhibits high chemical and radiation resistance.
 
Yesterday I spoke with a knowledgeable friend of mine. He had just fabricated new battery cables for his dump truck using "0" cable. He showed me a hand held hydraulic crimper (with various dies) that he bought at Harbor Freight. He was pleased with the crimping that he did with it. Having marine experience with cables in a salt water environment, he highly recommended working grease as far into the strands as possible.

Although the cable from www.euromotoelectrics.com. would seem to be the best choice.
 
Can't say that others have had problems but my bike is 20 years old and I made my own cable when I got the bike. It consists of a 14 gauge wire with a BNC connector on the end. The other part is the typical eye flange with the other half of the BNC connector welded on. That part stays on the transmission. The result being that every time I park the bike or need to work on it, I just twist the connector and off it comes. My battery lasts longer also.
 
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