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Old 04-26-2005, 09:12 AM   #31
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Resistance wise you'd have to be talking about a controlled situation where each bar or piece of wire is made from the same amount of material, but if you are, then it would be (from greatest to least..)

aluminum
gold
silver
copper

It's a misconception, especially in the audio industry that gold conducts better than copper. It doesn't. Gold audio ends and battery cable ends just look cooler, and tend to hold up better in non corrosive environments.

Quote:
also.. braid will flow more power then a bar...just look at the car stereo industry... 12 batteries in a car, all hooked with massive wire.. the oblect for car audio is efficiency...
That's a moot point. The reason car stereo people use standed cable for batteries is purely in cost and ease of use. It would be much harder to make thick enough bus-bars to jumper the batteries together that could handle the current load. Large gauge wire is cheap, bus bars are expensive. The side effect is yes, your right, standed wire flows more current.

For the small voltage/amper applications we're using, bars work just fine. The frequency and amperage of our draw keeps most of the current on the outside edge of the bar or wire anyway, so even if there is a difference in resistance it's so minor that testing for it is going to be inaccurate in itself.

You should be more worried about the loss through the ESC and the 12/14ga wires than which bus connectors you use.
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Old 04-26-2005, 09:15 AM   #32
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Quote:
Originally posted by jdwca
For the past six months, my favorite bar has been the Promatch bar. We'll be selling that on our website in the next few weeks. It has a very large contact patch allowing there to be flush contact between the bar and the cell surface as well as adequate room for a strong solder connection. It's also reasonably priced compared to the gold bars.
i looked briefly, and i believe that this bar is the same that brad has been using at hurricane for a long time. it is a stellar product, even beyond it's electrical abilities. they are burly as h*ll.
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Old 04-26-2005, 09:18 AM   #33
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Quote:
Originally posted by Desolas
Resistance wise you'd have to be talking about a controlled situation where each bar or piece of wire is made from the same amount of material, but if you are, then it would be (from greatest to least..)

aluminum
gold
silver
copper
hum, we've already got conflicting information. that didn't take long. i do believe that silver should be at the bottom of your list.
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Old 04-26-2005, 09:21 AM   #34
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yes copper , silver , Gold have very low numbers of resistance and they are very close. The ability to not corrode is a big factor on what metal to use because that in it self can raise resistance. Here is a small list of materials in order of conductivity that would surprize some of the guys on here!

* silver
* copper
* gold
* aluminum
* iron
* steel
* brass
* bronze
* mercury
* graphite
* dirty water
* concrete
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Old 04-26-2005, 09:27 AM   #35
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Quote:
Originally posted by Desolas
Resistance wise you'd have to be talking about a controlled situation where each bar or piece of wire is made from the same amount of material, but if you are, then it would be (from greatest to least..)

aluminum
gold
silver
copper

It's a misconception, especially in the audio industry that gold conducts better than copper. It doesn't. Gold audio ends and battery cable ends just look cooler, and tend to hold up better in non corrosive environments.



That's a moot point. The reason car stereo people use standed cable for batteries is purely in cost and ease of use. It would be much harder to make thick enough bus-bars to jumper the batteries together that could handle the current load. Large gauge wire is cheap, bus bars are expensive. The side effect is yes, your right, standed wire flows more current.

For the small voltage/amper applications we're using, bars work just fine. The frequency and amperage of our draw keeps most of the current on the outside edge of the bar or wire anyway, so even if there is a difference in resistance it's so minor that testing for it is going to be inaccurate in itself.

You should be more worried about the loss through the ESC and the 12/14ga wires than which bus connectors you use.

Aluminum is not suitable for Rc because it is for high current use. They use it for buildings were large cables are used because its lighter, cheaper, and can handle higher loads because it cools better . In Rc we dont have a load high enough to get current to flow through.
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Old 04-26-2005, 09:34 AM   #36
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Quote:
Originally posted by speedxl
yes copper , silver , Gold have very low numbers of resistance and they are very close. The ability to not corrode is a big factor on what metal to use because that in it self can raise resistance. Here is a small list of materials in order of conductivity that would surprize some of the guys on here!

* silver
* copper
* gold
* aluminum
* iron
* steel
* brass
* bronze
* mercury
* graphite
* dirty water
* concrete
nice work. how about adding tin, lead, and antimony (elements used in solder) to the list?
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Old 04-26-2005, 09:34 AM   #37
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Speedxl is correct about aluminum. As he said, it's generally used in high-current flow situations and not in comparatively small current uses like R/C.

I would also suggest that individual strand connections (heavy wire/braid) would theoretically result in lowered resistance, but a) they don't hold up nearly as well b) you'd have mostly solder-to-solder connections between the braid and battery surface.

Believe me, I used braid exclusively in the late 80's, early 90's. It's gets messy and ugly quickly.
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Old 04-26-2005, 09:36 AM   #38
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Quote:
Originally posted by Desolas


It's a misconception, especially in the audio industry that gold conducts better than copper. It doesn't. Gold audio ends and battery cable ends just look cooler, and tend to hold up better in non corrosive environments.

That's a moot point. The reason car stereo people use standed cable for batteries is purely in cost and ease of use. It would be much harder to make thick enough bus-bars to jumper the batteries together that could handle the current load. Large gauge wire is cheap, bus bars are expensive. The side effect is yes, your right, standed wire flows more current.
Yes the reason they use gold (plated) is for reasons of corrosion. The acids and gasses in an engine compartmant would corrode any connector. If gold were that bad then why would manufactures use gold plated connectors in modern cars. Last I saw ECU's, A/C control panels, even airbags in cars have gold plating!

And one major reason they dont use bars to connect batteries is vibration and chassis flex, which would distroy a a battery bar. If you look all automotive wiring its of a flex type its not a reliable method to hardwire anything in an automotive application.
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Old 04-26-2005, 09:49 AM   #39
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Quote:
Originally posted by seaball
nice work. how about adding tin, lead, and antimony (elements used in solder) to the list?
Sorry Seaball I will include that next time.

I was a Vw master tech for 8 years. I had to take a training course for proper repairs on electrical wiring. One of the no no's is soldering wires. The heat destroys the conductive flow, and corrosion will settle in later. Thus creating bigger problems. They did intensive testing and found that a proper fix and correct method is to use a connector and crimp it.

This has left me with the thought that hard soldering may not be effective for us.
Those gold banana connector may be the thing if we could crimp the wire in them

Seaball If I remember correctly I reconnected your wire at cleveland this year before your qualifier! You use connector dont you?
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Old 04-26-2005, 09:53 AM   #40
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Default Which is best??

I dont think what determines which bar is best has anythng to do with conductivity. Its application.

If say you have a six cell touring car that requires sadlle packs-the obvious choice for your jumper is braided wire. Its flat like a battery bar so it stores in your battery box well and it has a lot of surface area and is SUPER easy to solder on-unlike a piece of insulated 14g wire. SO you run solid bars on all cells-except your jumper.

Downside of course is if you dont take care handling your bateries out of the car-the stranded wire starts to fray-but hey-put another piece on!!

Outside of that-I dont think it really matters much.
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Old 04-26-2005, 10:03 AM   #41
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Ray - While I respect what your saying (hi, BTW), it actually matters quite a bit when you're competing for tenths.

I've probably tested hundreds of preassmebled/assembled batteries and you'd be surprised the difference proper connections can make when it comes to precious .01s of a volt that we count so dear on our Turbo35s.

I'm very meticulous (as anyone who knows me will tell you) about my soldering work. I can take the same quality cells and have one assembled properly with good quality bars and precise solder placement and have another pack which was sorta thrown together with smaller bars and tons of solder and I guarantee they will test something like this on a GFX:

Pack A
425, 7.08avg V, 15.5 AIR

Pack B
425, 7.01avg V, 19.8 AIR

Would you say a 1.18V, 2.7 AIR pack is going to 'feel' better than a 1.168V, 3.3 AIR pack?
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Old 04-26-2005, 10:06 AM   #42
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BTW, Seaball, not to hijack, but make sure you and Jim come on out to our race in June.
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Old 04-26-2005, 10:08 AM   #43
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Jon-I too wonder when on occasion I build up a killer new pack and it underperforms-did I blow it soldering it together? The only way of knowing is to desolder it-and send the cells through your TM.

Ray
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Old 04-26-2005, 10:10 AM   #44
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Quote:
Originally posted by speedxl
Seaball If I remember correctly I reconnected your wire at cleveland this year before your qualifier! You use connector dont you?
indeed you did. though, i don't believe i had connected it in the first place. i don't like the idea of applying heat to the same two cells time and again, over the life of the pack. not so much for a performance benefit.
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Old 04-26-2005, 10:17 AM   #45
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Ray - I can't tell you how many times this happens with people. I've actually had this happen with team drivers in the distant past. I'll give them the same quality cells I built for myself, but they'll complain that it only cycled at 1.165V or something and mine cycled at 1.185V. When you try to explain to them that they possibly soldered incorrectly or applied too much heat or used cruddy bars or something, they cannot believe it would make such a difference.

Regarding soldering/unsoldering, I usually just tell guys to purchase new packs once they're considering rezapping/rematching. Usually the cells have developed so much memory by then, the only thing to do is sell them or deadshort them if they haven't already done so.

As Seaball said unsoldering and resoldering old packs is generally a no-no for competition racing.
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