Main cable.

[738 driver]

With ever increasing displacements/CR's/HP's in combination with our miserable UK temps, has anyone considered/upgraded the main battery cable during their build.
Just about to fit the brake lines and as I did not pick-up the battery cables from the factory am looking at making up my own (buying materials from a mate in the trade).

For the electrical gurus would 35-40mm2 (12-14mm OD) be an increase over the standard factory cable?

I might end up with a 10mtr roll and only need 4-5 so there may well be 50% spare and the appropriate P clips if anyone else is interested at some lowly price plus postage.

[carsounds_dan]

go to your local welding place, welding wire is just as pure as any other and alot cheaper.. It's what I do when I do big stereo builds for customers, I can keep the costs low enough to undercut most people that way

[60mph]

My factory cable is adequate with SBC 6.3L @ 9.8 compression with 4'' diameter pistons.500 nominal bhp.I have had starting problems[not the car !]and I am amazed how 'chirpy' the battery is.I flooded the connectors with solder , same on earth straps.My factory cable has fine strands.

Frank

[738 driver]

Cheers gents..........the factory also use welding cable...as I plan to, just unsure whether theirs is single or double insulated and what the total OD is?

Running a bit more C/R Frank (11.5), also here in the depths of Lancashire the weather seems to be endlessly cold,grotty and wet. Those are the main reasons I considered the upgrade plus its not really any additional expense.... actually might be a bit cheaper and only a few additional grams/ounces!
rgds
Dave

Edited by 738 driver on Wednesday 4th March 21:15

[ROWDYRENAULT]

This may sound backwards to some but a correctly swedged fitting onto electrical lines is the right way to attach them rather than sodiering. The connection will transmit more amps over a longer period of time than one that is sodiered. #2 multistrand wire used for ground wires in welding with proper ends will carry all the amps that your starter will ever use.

[spatz]

first of all soldering is not the preferred choice in vibrating environments, sooner or later it will crack, and good luck soldering a battery cable,
you will have some problem finding a soldering iron for that task !!!

[Steve_D]

Just to add further weight to the comments.
The cable ends should be crimped with the correct tool and not soldered. The solder will run down the strands and stiffen the cable as it exits the terminal. This will cause it to break under vibration.

Steve

[738 driver]

Thanks gents........I have crimp type connectors.

I think Frank may have just solder-flooded his pre-crimped cables.....Frank?

[60mph]

I had a problem with my wiring harness in that some of the connectors were lying in the bottom of the box [I rest my case ] so I took them all off and soldered new ones back on .The LAST thing I wanted was electrical problems when stressed / running the car for the first time .With the battery cables the existing crimps appeared ok but I soldered them as well as this could only improve their conductivity.You have to use a blowlamp with the terminal '' cable up''then solder.With the Astons I used to make my own cables for the battery which was in the boot.These comprised very heavily stranded cable which was a push fit into the connector then soaked in acid then soldered with a blowlamp.That was HOW it was done in those days.There was no crimping which is just cheaper now technically possible .To test the cables I used a redundant giant 12v battery and short circuited it with the cables.Never had melted solder . Copper will conduct heat quicker than any current you are likely to encounter.Why should soldered cables break with vibration?With a crimped joint you have a sudden change from where the cable is held rigid in it's connector to where it is free hanging so presumably the leverage is where it enters the joint.Vibration presumaly= work hardening so why dont crimped cables break? I've never seen it but have never raced .I HATE CRIMPED CABLES = allows capillary corrosion in unless done under factory conditions and proper greased and '' o '' ringed watertight connectors used.I've soldered my cables for 47 years now and have never nad a brocken cable.All my work has been caused by having to cut off unreliable/corroded crimped joints.
Each to their own perhaps.

Frank

[ezakimak]

copper battery terminal,
copper cable,



make sure you don’t use and aluminium lug.

or you will get a dissimilar metal reduction and oxidisation reaction (rust) between the two. this will then form a high resistance point.
if crimping a hexagonal crimp is more reliable.
Soldering should illuminate all the air – and limit the oxidisation of the copper within the joint.

[738 driver]

Copper/copper........ Dont forget your Vaseline gents (no LM grease thanks)!

Actually there are several theories on this subject..... dissimilar metal does seem to be the common denominator in all of them. The landrover boys claim to go through winch feeds at an alarming rate in their hostile operating environment...most having changed to marine-grade power cable. Not sure what material they connect with though?
Was copper/brass or copper/gold not supposed to be best?
Anyhow I only want a big fat cable to help retain the current over its 4mtr journey....just to help turn over mi lowly SBC!

[60mph]

Another thought ; the spade/connector is old fashioned not waterproof system.When I built mine I squirted waxoil in every connector inside and out.

Also some HD battery terminals come ready drilled so you can feed the molticore solder through the side wall.

Frank

[ROWDYRENAULT]

I have never done this on this forum before BUTTTT. When I stated in an earlier post that crimped cables are the way to go for high voltage main feeds that wasn't a maybe. that is the way it should be done period. The study that I quote was done to aerospace standards right crimping tool correct end piece ect vs the right soder, heat range ect. The crimped connection flows more amps longer and is less influenced by corrison and vibration. The study states that crimping done correctly causes a molucular bond between the end piece and the wire.

[738 driver]

Correct, Aerospace do use high voltage/low current, typically 115V400HZ/5- 50amps... this way more useful end-power is available through a far thinner wire..... Thinner, lower mass wires are good in flying things...more fuel/pax/weapons over less wire and solder = enhanced performance/profit.

However this is low voltage/high current.....so does the same apply here?

You'd have to agree Rowdy, Franks soldered connections were a big improvement on the ones lying on the bottom of the packaging!

Edited by 738 driver on Thursday 5th March 19:49

Edited by 738 driver on Thursday 5th March 20:56

[hackin'n'bashin]

copper and gold do not go together in harsh environments such as the engine bay, their anodic index puts them too far apart. you may as well use lead (the difference is the same!!)

if your being picky, the only metals to use with copper are, more copper, nickel brass or bronze.

[60mph]

The Airbus A380 uses aluminium wires in the wiring harness.Presumably with crimped connectors.Also the 400,000volt National grid have been using aluminium wires between pylons I think ever since they could make the cables as this is the most efficient way to ''transport'' electricity.Also I have seen copper multistrand wire which appears to have been spot welded to the terminal and if you open it all up to investigate it is impossible to pull the wire off;you have to bend it back and forth 'till it breaks off leaving the spot weld in place and the far end of the cable still in strands as original.

[738 driver]

Cheers again Hackin.....
....I must admit, as a lowly Lo-Cost driver gold connectors were never in the running!

Anyway its decided now, 60mm2 quality cable and copper crimp connectors shrink-wrapped, should start a V12 diesel over that distance!

Edited by 738 driver on Thursday 5th March 19:56

[ezakimak]

we use products from these two companies - work fine for the 4000 amps we pull through the 300mm^2 cables.

http://cembre.com/asp/pdf/eng_RAIL_connectionAR.pd...

http://www.erico.com/

[ROWDYRENAULT]

GUYS I fly helicopters, most of my career in medium size Bell Helicopters. Aircraft in this weight class use 28 volt systems and then inverters when they need a/c current. This limits the ammount of A/C to a fairly low amprage. Since 2000 I have been flying Sikorsky Blackhawks a much more exspensive and complex helicopter and yes they use A/C systems as the fellow said above. The point being that in the high amp 28 volt start system in 28 volt aircraft the start sequence will see 600 amps for 25 seconds. These cables are always crimped copper on copper. As far as the alluminum wire in the Airbus 380 goes I do not know for a fact that you are wrong, but aluminum wire in aircraft in general is a big no no because it will not carry the same amperage as the same size copper wire. Lee

[738 driver]

Off-topic Lee but does the Bell use a combined starter/generator unit similar to King-Airs/PT6 etc? A unit about the size of a washing machine drum?
Did some time in later B200's and remember they did draw a lot on start-up........The aircraft were the engineers babies though, so although several of the drivers were interested in systems, we would never dare open them up to have a look around!!!